Extended DateTimePicker

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• Download demo project - 11.7 Kb

Introduction

This article describes an extension of the MS DateTimePicker.

Background

I developed this control to meet the needs of a client. In a database application I am developing, my clients requirements are that I display dates and times as blank, unless a valid date or time is entered. Additionally they wanted to display a separate field with the day of the week associated with the date entered, and also dates with an associated AM or PM, but no specific time.

To achieve this I built a composite control based on the DateTimePicker class.

The control sub classes the System.Windows.Forms.DateTimePicker control, and I added a TextBox to the DateTimePicker so that it sits in front of the DateTime display area, and allows the user to enter a date and or time, and which displays the date and or time according to the format Selected. A Tooltip object and an ErrorProvider were also included with the control. I may have gone a little overboard with the format options, but a couple of the stranger ones are necessary for me to display the data the way the client wants.

To begin with, I overrode the DateTimePicker's standard Format property, set it to Browsable(false) and gave it a single accessor get, which returns base.Format. The standard Format property is no longer available in the Properties Window, and it cannot be set external to the new control.

Next I defined a new property FormatEx, which is browsable and is of Type enum dtpCustomExtensions, which is an enumeration of all the possible date and time formats this control handles as standard. They include dtpLong, dtpShort, dtpTime and dtpCustom, which provide duplicate functionality to the standard Long, Short, Time and Custom attributes formerly selectable from the Format Property. The standard Format property is set permanently to Custom.

InitialiseCustomMessage() is called whenever FormatEx is set to a new value, InitialiseCustomMessage() sets the appropriate message in the Tooltip, to be displayed when the mouse hovers over the control.

FormatTextBox() is called whenever it is necessary to display a date or time in the TextBox.

There is some localization, but as all messages are hard coded in English, the control is really only useful in English speaking countries. The user can enter any valid date (valid according to the current local) into the TextBox, this will be parsed and redisplayed according to the formatting rules associated with the current selected FormatEx value.

A number of standard DateTimePicker properties have been overridden, these include ShowUpDown and ShowCheckBox. I wanted to ensure that these, along with the new property ShowButtons, which hides/unhide the buttons, were locked to false when the new property ReadOnly was true. ReadOnly sets/gets the TextBox ReadOnly property and acts to expose it in the property window, and makes that functionality available to the control.

I have added one other property LinkTo, which allows me to associate an instance of the control to one or more instances of the TAS.Widgets.DateTimePicker control. Using this, it is possible to synchronize the values of one or more controls with a master instance, so that I can display, for example, a date in one and the day of the week in another.

To Link other instances of the TAS.Widgets.DateTimePicker to a master instance add the name(s) of the linked controls to the LinkTo property of the master instance in the form of ChildControlName1,ChildControlName2,ChildControlName3 etc.

Using the code

To run the demo application, download DTP_Example.zip, and extract the files into a directory. The demo application WindowsApplication2.exe requires the file DateTimePicker.dll. If these two files are not extracted, the runtime error System.IO.FileNotFoundException has occurred in WindowsApplication2.exe will appear.

If you find this control useful, create a directory called TracyAnneSofware (or any name you like) and move it into that directory, then, if you use the Visual Studio IDE, add it to the tool box.

The code

using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Windows.Forms;
using TAS.Widgets;

namespace TAS.Widgets
{
    public class DateTimePicker : System.Windows.Forms.DateTimePicker
    {
        private System.Windows.Forms.TextBox txtDateTime;
        private System.ComponentModel.IContainer components;

        private bool SetDate;
        private System.Windows.Forms.ErrorProvider ErrorMessage;
        private System.Windows.Forms.ToolTip Tooltip;

        private const int BTNWIDTH = 16;

        public enum dtpCustomExtensions
        {
            dtpLong = 0,
            dtpShort = 1,
            dtpTime = 2,
            dtpShortDateShortTimeAMPM = 3,
            dtpShortDateLongTimeAMPM = 4,
            dtpShortDateShortTime24Hour = 5,
            dtpShortDateLongTime24Hour = 6,
            dtpLongDateShortTimeAMPM = 7,
            dtpLongDateLongTimeAMPM = 8,
            dtpLongDateShortTime24Hour = 9,
            dtpLongDateLongTime24Hour = 10,
            dtpSortableDateAndTimeLocalTime = 11,
            dtpUTFLocalDateAndShortTimeAMPM = 12,
            dtpUTFLocalDateAndLongTimeAMPM = 13,
            dtpUTFLocalDateAndShortTime24Hour = 14,
            dtpUTFLocalDateAndLongTime24Hour = 15,
            dtpShortTimeAMPM = 16,
            dtpShortTime24Hour = 17,
            dtpLongTime24Hour = 18,
            dtpYearAndMonthName = 19,
            dtpMonthNameAndDay = 20,
            dtpYear4Digit = 21,
            dtpMonthFullName = 22,
            dtpMonthShortName = 23,
            dtpDayFullName = 24,
            dtpDayShortName = 25,
            dtpShortDateAMPM = 26,
            dtpShortDateMorningAfternoon = 27,
            dtpCustom = 28
    }

        private string mvarLinkedTo;
        private bool bDroppedDown;
        private int ButtonWidth = BTNWIDTH;
        private bool mvarShowButtons = true;
        private dtpCustomExtensions mvarFormatEx;
        private string mvarCustomFormatMessage;
        private int CheckWidth = 0;

        private TAS.Widgets.DateTimePicker LinkTo;
        private System.Collections.ArrayList 
          LinkToArray = new System.Collections.ArrayList();
        private System.Collections.ArrayList 
          LinkedArray = new System.Collections.ArrayList();

        #region Constructor and destructor

        public DateTimePicker()
        {
            // This call is required by the Windows.Forms Form Designer.
            InitializeComponent();

            // TODO: Add any initialization after the InitForm call
            //Initialise bas.Format to Custom, 
            //we only need Custom Format
            base.Format = 
               System.Windows.Forms.DateTimePickerFormat.Custom;
            DateTimePicker_Resize(this, null);

        }

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        protected override void Dispose( bool disposing )
        {
            if( disposing )
            {
                if( components != null )
                    components.Dispose();
            }
            base.Dispose( disposing );
        }

        #endregion Constructor and destructor

        #region Component Designer generated code
        /// <summary>
        /// Required method for Designer support - do not modify 
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.components = new System.ComponentModel.Container();
            this.txtDateTime = new System.Windows.Forms.TextBox();
            this.ErrorMessage = new System.Windows.Forms.ErrorProvider();
            this.Tooltip = new 
               System.Windows.Forms.ToolTip(this.components);
            this.SuspendLayout();
            // 
            // txtDateTime
            // 
            this.txtDateTime.Location = new System.Drawing.Point(20, 49);
            this.txtDateTime.MaxLength = 50;
            this.txtDateTime.Name = "txtDateTime";
            this.txtDateTime.TabIndex = 0;
            this.txtDateTime.Text = "";
            this.txtDateTime.BackColorChanged += 
              new System.EventHandler(this.txtDateTime_BackColorChanged);
            this.txtDateTime.Leave += 
              new System.EventHandler(this.txtDateTime_Leave);
            this.txtDateTime.Enter += 
              new System.EventHandler(this.txtDateTime_Enter);
            // 
            // ErrorMessage
            // 
            this.ErrorMessage.DataMember = null;
            // 
            // DateTimePicker
            // 
            this.Controls.AddRange(new System.Windows.Forms.Control[] 
               {this.txtDateTime});
            this.Value = new System.DateTime(1753, 1, 1, 15, 8, 40, 119);
            this.DropDown += 
              new System.EventHandler(this.DateTimePicker_DropDown);
            this.FontChanged += 
              new System.EventHandler(this.DateTimePicker_FontChanged);
            this.Resize += 
              new System.EventHandler(this.DateTimePicker_Resize);
            this.Enter += 
              new System.EventHandler(this.DateTimePicker_Enter);
            this.CloseUp += 
              new System.EventHandler(this.DateTimePicker_CloseUp);
            this.ForeColorChanged += 
              new System.EventHandler
              (this.DateTimePicker_ForeColorChanged);
            this.BackColorChanged += 
              new System.EventHandler
              (this.DateTimePicker_BackColorChanged);
            this.ValueChanged += 
              new System.EventHandler(this.FormatOrValueChanged);
            this.FormatChanged += 
              new System.EventHandler(this.FormatOrValueChanged);
            this.ResumeLayout(false);

        }
        #endregion

        #region overriden and additional properties

        //OverRide Formst and hide it by setting 
        //Browsable false, make it read only
        //so it can't be written to, it will always be Custom anyway
        [Browsable(false)]
        public new System.Windows.Forms.DateTimePickerFormat Format
        {
            get
            {
                return base.Format;
            }
            //set
            //{
            //    base.Format = value;
            //}
        }

        //FormatEx, extends the formatting options 
        //by allowing additional selections
        //Replaces Format
        [Browsable(true), Category("Appearance"), 
          Description("Format Extensions replaces Format 
          gets sets display Formats")]
        public dtpCustomExtensions FormatEx
        {
            get
            {
                return mvarFormatEx;
            }
            set
            {
                mvarFormatEx = value;
                InitialiseCustomMessage();
            }
        }

        //New Property, allows hiding of DropDown 
        //Button and Updown Button
        [Browsable(true), Category("Appearance"), 
          Description("Hides DropDown and Spin Buttons, 
          Allows keyed entry only.")] 
        public bool ShowButtons
        {
            get
            {
                return mvarShowButtons;
            }
            set
            {
                //Do not allow Set Show Buttons when ReadOnly is true
                //all Buttons and Chexkbox are hidden 
                //when Control is Read Only
                if (!this.ReadOnly)
                {
                    mvarShowButtons = value;
                    if (mvarShowButtons)
                    {
                        ButtonWidth = BTNWIDTH;
                    }
                    else
                    {
                        ButtonWidth = 0;
                    }
                    DateTimePicker_Resize(this, null);
                }
            }
        }

        //Overrides base.ShowCheckBox
        [Browsable(true), Category("Appearance"), 
          Description("Hides DropDown and Spin Buttons, 
          Allows keyed entry only.")]
        public new bool ShowCheckBox
        {
            get
            {
                return base.ShowCheckBox;
            }
            set
            {
                //Do not allow set ShowCheckBox when ReadOnly is True
                //all Buttons and Chexkbox are hidden 
                //when Control is Read Only
                if (!this.ReadOnly)
                {
                    base.ShowCheckBox = value;
                    if (base.ShowCheckBox)
                    {
                        CheckWidth = BTNWIDTH;
                    }
                    else
                    {
                        CheckWidth = 0;
                    }
                    DateTimePicker_Resize(this,null);
                }
            }
        }
        
        //overrie Text, we want to set Get Textbox Text
        [Browsable(true), Category("Behavior"), 
          Description("Date and Time displayed")]
        public new string Text
        {
            get
            {
                return txtDateTime.Text;
            }
            set
            {
                txtDateTime.Text = value;
                //Don't bother Formatting the Textbox 
                //if it's value is NullString
                //It will cause problems if you do
                if (value != "")
                {
                    FormatTextBox();
                }
            }
        }

        //Override bas.ShowUpDown
        [Browsable(true), Category("Appearance"), 
          Description("Uses Updown control to select 
          dates instead of Dropdown control")]
        public new bool ShowUpDown
        {
            get
            {
                return base.ShowUpDown;
            }
            set
            {
                //Do not allow set ShowUpDown when ReadOnly is True
                //all Buttons and Checkbox are 
                //hidden when Control is Read Only
                if (!this.ReadOnly)
                {
                    base.ShowUpDown = value;
                    txtDateTime.Text = "";
                }
            }
        }

        //Override Textbox back Colour so we can 
        //add it to the Appearance List
        //and use it to set the BG colour
        [Browsable(true), Category("Appearance"), 
          Description("The Backround Colour user to display 
          Text and Graphics in this Control")]
        public new System.Drawing.Color BackColor
        {
            get
            {
                return base.BackColor;
            }
            set
            {
                base.BackColor = value;
            }
        }

        //New Property Read Only makes it possible 
        //to set Textbox to read only
        [Browsable(true), Category("Behavior"), 
          Description("Used to set whether the 
                      control can be edited")]
        public bool ReadOnly
        {
            get
            {
                return txtDateTime.ReadOnly;
            }
            set
            {
                //If ReadOnly is true make sure 
                //ShowCheckBox, ShowUpDown and ShowButtons 
                //are false.
                //all Buttons and Checkbox are hidden 
                //when Control is Read Only
                //Be aware of the order these properties are set
                if (value)
                {
                    this.ShowCheckBox = false;
                    this.ShowUpDown = false;
                    this.ShowButtons = false;
                    txtDateTime.ReadOnly = value;
                }
                else
                {
                    txtDateTime.ReadOnly = value;
                    this.ShowButtons = true;
                }
            }
        }

        //New Property Makes it possible to link 
        //control to another Datetimepicker
        [Browsable(true), Category("Behavior"), 
          Description("Set Get another Date Picker Control 
          that this control receives data from.")]
        public string LinkedTo
        {
            get
            {
                return mvarLinkedTo;
            }
            set
            {
                mvarLinkedTo = value;
                LinkedArray.Clear();
                if (mvarLinkedTo != "" && mvarLinkedTo != null)
                {
                    string[] splitmvarLinkedTo = 
                       mvarLinkedTo.Split(",".ToCharArray());
                    for (int i = 0; i < splitmvarLinkedTo.Length; i++)
                    {    
                        LinkedArray.Add(splitmvarLinkedTo[i].Trim());
                    }
                }
            }
        }

        #endregion

        #region DateTimePicker events

        private void DateTimePicker_Resize(object sender, 
                                        System.EventArgs e)
        {
            this.txtDateTime.Location = new 
              System.Drawing.Point(-2 + CheckWidth, -2);
            this.txtDateTime.Size = new 
              System.Drawing.Size(this.Width - ButtonWidth - CheckWidth, 
              this.Height);
        }

        private void DateTimePicker_FontChanged(Object sender, 
                                            System.EventArgs e  ) 
        {
            //Make sure TextBox Font =  Dtp Font
            txtDateTime.Font = this.Font;
        }

        private void DateTimePicker_BackColorChanged(Object sender, 
                                                 System.EventArgs e)
        {
            //Make sure TextBox BackColour =  Dtp Back Colour
            txtDateTime.BackColor = this.BackColor;
        }

        private void txtDateTime_BackColorChanged(Object sender, 
                                             System.EventArgs e)
        {
            //Make sure DTP BackColour =  TextBox Back Colour
            if (txtDateTime.BackColor != this.BackColor)
            {
                this.BackColor = txtDateTime.BackColor;
            }
        }

        private void DateTimePicker_ForeColorChanged(Object sender, 
                                                System.EventArgs e)
        {
            //Make sure TextBox Fore Colour =  Dtp Fore Colour
            txtDateTime.ForeColor = this.BackColor;
        }

        private void FormatOrValueChanged(Object sender, 
                                       System.EventArgs e) 
        {
            ErrorMessage.SetError(this, "");

            //if dtp Value changed 
            //Attempt to Format the TextBox String 
            //if Text is not NullString
            if (this.Text != "" )
            {
                try
                {
                    FormatTextBox();
                }
                catch
                {
                    ErrorMessage.SetError(this, "Invalid Date - " 
                       + txtDateTime.Text + ", valid format is " 
                       + mvarCustomFormatMessage);
                }
            }
        }

        private void txtDateTime_Enter(Object sender, 
                                    System.EventArgs e  ) 
        {
            Tooltip.SetToolTip(txtDateTime, mvarCustomFormatMessage);

            if (txtDateTime.Text.Length > 0 )
            {
                txtDateTime.SelectionStart = 0;
                txtDateTime.SelectionLength = 
                         txtDateTime.Text.Length;
            }

            SetDate = true;
            this.Value = DateTime.Now;
            SetDate = false;
        }

        private void txtDateTime_Leave(Object sender, 
                                     System.EventArgs e ) 
        {
            if (! SetDate )
            {
                SetDate = true;

                ErrorMessage.SetError(this, "");

                //Attempt to Format the TextBox String 
                //if Text is not NullString
                if (this.Text != "" )
                {
                    try
                    {
                        FormatTextBox();
                        //if Link To is Not nullString
                        //Attempt to Link to the Specified LinkTo Controls
                        LinkToArray.Clear();
                        if (mvarLinkedTo != "" && mvarLinkedTo != null)
                        {
                          for (int j = 0; j < LinkedArray.Count; j++)
                          {
                            for (int i = 0; 
                               i < this.Parent.Controls.Count; i++)
                            {
                              if (this.Parent.Controls[i].Name == 
                                     LinkedArray[j].ToString() && 
                                     this.Parent.Controls[i] is 
                                     TAS.Widgets.DateTimePicker)
                              {
                                LinkTo = (TAS.Widgets.DateTimePicker)
                                               this.Parent.Controls[i];
                                LinkToArray.Add(LinkTo);
                                break;
                              }
                            }
                          }
                        }
                    }
                    catch 
                    {
                        ErrorMessage.SetError(this, "Invalid Date - " + 
                           txtDateTime.Text + ", valid format is " + 
                           mvarCustomFormatMessage);
                    }
                }

                //IF the LinkTo Object has been instantiated it's 
                //ok to attempt to set it's Text Value
                for (int i = 0; i < LinkToArray.Count; i++)
                {
                    if (this.LinkToArray[i] != null)
                    {
                        LinkTo = (TAS.Widgets.DateTimePicker)
                                                 LinkToArray[i];
                        LinkTo.Text = this.Text;
                    }
                }

                SetDate = false;
            }
        }

        private void DateTimePicker_Enter(Object sender, 
                                       System.EventArgs e)
        {
            txtDateTime.Focus();
        }

        private void DateTimePicker_DropDown(Object sender, 
                                         System.EventArgs e) 
        {
            bDroppedDown = true;
        }

        private void DateTimePicker_CloseUp(object sender, 
                                         System.EventArgs e)
        {
            if (bDroppedDown || this.ShowUpDown )
            {
                if (! SetDate )
                {
                    txtDateTime.Text = this.Value.ToString();
                    FormatTextBox();
                    bDroppedDown = false;
                    txtDateTime.Focus();
                }
            }
        }
    
        protected override void 
               OnValueChanged(System.EventArgs eventargs)
        {
            
            
            if (bDroppedDown || this.ShowUpDown )
            {
                if (! SetDate )
                {
                    txtDateTime.Text = this.Value.ToString();
                    FormatTextBox();
                }
            }
        }
        
        //Set up the message that will diplay in the Tooltip
        //when the mouse is hovered over the control
        private void InitialiseCustomMessage()
        {
            switch (mvarFormatEx)
            {
                case dtpCustomExtensions.dtpCustom:
                    mvarCustomFormatMessage = this.CustomFormat;
                    break;
                case dtpCustomExtensions.dtpLong:
                    mvarCustomFormatMessage = "Long Date (" + 
                         DateTime.Now.ToLongDateString() + ")";
                    this.CustomFormat = "yyyy-MM-dd HH:mm:ss";
                    break;
                case dtpCustomExtensions.dtpShort:
                    mvarCustomFormatMessage = "Short Date (" + 
                        DateTime.Now.ToShortDateString() + ")";
                    this.CustomFormat = "yyyy-MM-dd HH:mm:ss";
                    break;
                case dtpCustomExtensions.dtpTime:
                    mvarCustomFormatMessage = "Long Time AM/PM (" + 
                        DateTime.Now.ToLongTimeString() + ")";
                    this.CustomFormat = "HH:mm:ss yyyy-MM-dd ";
                    break;
                case dtpCustomExtensions.dtpDayFullName:
                    mvarCustomFormatMessage = 
                        "Day of the Week Full Name (" + 
                        DateTime.Now.ToString("dddd", 
                        Application.CurrentCulture) + ")";
                    this.CustomFormat = "dd-MM-yyyy HH:mm:ss";
                    break;
                case dtpCustomExtensions.dtpDayShortName:
                    mvarCustomFormatMessage = 
                       "Day of the Week Short Name (" 
                       + DateTime.Now.ToString("ddd", 
                       Application.CurrentCulture) + ")";
                    this.CustomFormat = "dd-MM-yyyy HH:mm:ss";
                    break;
                case dtpCustomExtensions.dtpLongDateLongTime24Hour:
                    mvarCustomFormatMessage = 
                       "Long Date Long Time 24 Hour (" + 
                       DateTime.Now.ToString("D", 
                       Application.CurrentCulture) + " " + 
                       DateTime.Now.ToString("HH:mm:ss", 
                       Application.CurrentCulture) + ")";
                    this.CustomFormat = "yyyy-MM-dd HH:mm:ss";
                    break;
                case dtpCustomExtensions.dtpLongDateLongTimeAMPM:
                    mvarCustomFormatMessage = 
                       "Long Date Long Time AM/PM (" + 
                       DateTime.Now.ToString("D", 
                       Application.CurrentCulture) + " " + 
                       DateTime.Now.ToString("hh:mm:ss tt", 
                       Application.CurrentCulture) + ")";
                    this.CustomFormat = "yyyy-MM-dd HH:mm:ss";
                    break;
                case dtpCustomExtensions.dtpLongDateShortTime24Hour:
                    mvarCustomFormatMessage = 
                       "Long Date Short Time 24 Hour (" + 
                       DateTime.Now.ToString("D", 
                       Application.CurrentCulture) + " " + 
                       DateTime.Now.ToString("HH:mm", 
                       Application.CurrentCulture) + ")";
                    this.CustomFormat = "yyyy-MM-dd HH:mm:ss";
                    break;
                case dtpCustomExtensions.dtpLongDateShortTimeAMPM:
                    mvarCustomFormatMessage = 
                       "Long Date Short Time AM/PM (" + 
                       DateTime.Now.ToString("D", 
                       Application.CurrentCulture) + " " + 
                       DateTime.Now.ToString("hh:mm tt", 
                       Application.CurrentCulture) + ")";
                    this.CustomFormat = "yyyy-MM-dd HH:mm:ss";
                    break;
                case dtpCustomExtensions.dtpLongTime24Hour:
                    mvarCustomFormatMessage = 
                       "Long Time 24 Hour (" + 
                       DateTime.Now.ToString("HH:mm:ss", 
                       Application.CurrentCulture) + ")";
                    this.CustomFormat = "HH:mm:ss yyyy-MM-dd ";
                    break;
                case dtpCustomExtensions.dtpMonthFullName:
                    mvarCustomFormatMessage = 
                        "Month Full Name (" + 
                        DateTime.Now.ToString("MMMM", 
                        Application.CurrentCulture) + ")";
                    this.CustomFormat = "MM-dd-yyyy HH:mm:ss";
                    break;
                case dtpCustomExtensions.dtpMonthNameAndDay:
                    mvarCustomFormatMessage = 
                        "Month Name and Day (" + 
                        DateTime.Now.ToString("M", 
                        Application.CurrentCulture) + ")";
                    this.CustomFormat = "dd-MM-yyyy HH:mm:ss";
                    break;
                case dtpCustomExtensions.dtpMonthShortName:
                    mvarCustomFormatMessage = 
                        "Month Short Name (" + 
                        DateTime.Now.ToString("MMM", 
                        Application.CurrentCulture) + ")";
                    this.CustomFormat = "MM-dd-yyyy HH:mm:ss";
                    this.CustomFormat = "yyyy-MM-dd HH:mm:ss";
                    break;
                case dtpCustomExtensions.dtpShortDateLongTime24Hour:
                    mvarCustomFormatMessage = 
                        "Short Date Long Time 24 Hour (" + 
                        DateTime.Now.ToString("d", 
                        Application.CurrentCulture) + " " + 
                        DateTime.Now.ToString("HH:mm:ss", 
                        Application.CurrentCulture) + ")";
                    this.CustomFormat = "yyyy-MM-dd HH:mm:ss";
                    break;
                case dtpCustomExtensions.dtpShortDateLongTimeAMPM:
                    mvarCustomFormatMessage = 
                        "Short Date Long Time AM/PM (" + 
                        DateTime.Now.ToString("G", 
                        Application.CurrentCulture) + ")";
                    this.CustomFormat = "yyyy-MM-dd HH:mm:ss";
                    break;
                case dtpCustomExtensions.dtpShortDateShortTime24Hour:
                    mvarCustomFormatMessage = 
                        " Short Date Short Time 24 Hour (" + 
                        DateTime.Now.ToString("d", 
                        Application.CurrentCulture) + " " + 
                        DateTime.Now.ToString("HH:mm", 
                        Application.CurrentCulture) + ")";
                    this.CustomFormat = "yyyy-MM-dd HH:mm:ss";
                    break;
                case dtpCustomExtensions.dtpShortDateShortTimeAMPM:
                    mvarCustomFormatMessage = 
                        " Short Date Short Time AM/PM (" + 
                        DateTime.Now.ToString("d", 
                        Application.CurrentCulture) + " " + 
                        DateTime.Now.ToString("hh:mmss tt", 
                        Application.CurrentCulture) + ")";
                    this.CustomFormat = "yyyy-MM-dd HH:mm:ss";
                    break;
                case dtpCustomExtensions.dtpShortTime24Hour:
                    mvarCustomFormatMessage = 
                        "Short Time 24 Hour (" + 
                        DateTime.Now.ToString("HH:mm", 
                        Application.CurrentCulture) + ")";
                    this.CustomFormat = "HH:mm:ss yyyy-MM-dd ";
                    break;
                case dtpCustomExtensions.dtpShortTimeAMPM:
                    mvarCustomFormatMessage = 
                        "Short Time AM/PM (" + 
                        DateTime.Now.ToString("hh:mm tt", 
                        Application.CurrentCulture) + ")";
                    this.CustomFormat = "HH:mm:ss yyyy-MM-dd ";
                    break;
                case dtpCustomExtensions.dtpSortableDateAndTimeLocalTime:
                    mvarCustomFormatMessage = 
                        "Sortable Date and Local Time (" + 
                        DateTime.Now.ToString("s", 
                        Application.CurrentCulture) + ")";
                    this.CustomFormat = "yyyy-MM-dd HH:mm:ss";
                    break;
                case dtpCustomExtensions.dtpUTFLocalDateAndLongTime24Hour:
                    mvarCustomFormatMessage = 
                        "UTF Local Date and Long Time 24 Hour (" + 
                        DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss", 
                        Application.CurrentCulture) + ")";
                    this.CustomFormat = "yyyy-MM-dd HH:mm:ss";
                    break;
                case  dtpCustomExtensions.dtpUTFLocalDateAndLongTimeAMPM:
                    mvarCustomFormatMessage = 
                        "UTF Local Date and Long Time AM/PM (" + 
                        DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss tt", 
                        Application.CurrentCulture) + ")";
                    this.CustomFormat = "yyyy-MM-dd HH:mm:ss";
                    break;
                case  dtpCustomExtensions.dtpUTFLocalDateAndShortTime24Hour:
                    mvarCustomFormatMessage = 
                        "UTF Local Date and Short Time 24 Hour (" + 
                        DateTime.Now.ToString("yyyy-MM-dd HH:mm", 
                        Application.CurrentCulture) + ")";
                    this.CustomFormat = "yyyy-MM-dd HH:mm:ss";
                    break;
                case  dtpCustomExtensions.dtpUTFLocalDateAndShortTimeAMPM:
                    mvarCustomFormatMessage = 
                        "UTF Local Date and Short Time AM/PM (" + 
                        DateTime.Now.ToString("yyyy-MM-dd HH:mm tt", 
                        Application.CurrentCulture) + ")";
                    this.CustomFormat = "yyyy-MM-dd HH:mm:ss";
                    break;
                case  dtpCustomExtensions.dtpYear4Digit:
                    mvarCustomFormatMessage = "4 Digit Year (" + 
                        DateTime.Now.ToString("yyyy", 
                        Application.CurrentCulture);
                    this.CustomFormat = "yyyy-MM-dd HH:mm:ss";
                    break;
                case  dtpCustomExtensions.dtpYearAndMonthName:
                    mvarCustomFormatMessage = 
                        "Year and Month Name (" + 
                        DateTime.Now.ToString("Y", 
                        Application.CurrentCulture) + ")";
                    this.CustomFormat = "MM-dd-yyyy HH:mm:ss";
                    break;
                case  dtpCustomExtensions.dtpShortDateAMPM:
                    mvarCustomFormatMessage = "Short Date AM/PM (" + 
                        DateTime.Now.ToString("d", 
                        Application.CurrentCulture) + " " + 
                        DateTime.Now.ToString("tt", 
                        Application.CurrentCulture) + ")";
                    this.CustomFormat = "MM-dd-yyyy HH:mm:ss";
                    break;
                case  dtpCustomExtensions.dtpShortDateMorningAfternoon:
                    string AMPM = "AM";
                    if (DateTime.Now.Hour >= 12)
                    {
                        AMPM = "Afternoon";
                    }
                    mvarCustomFormatMessage = 
                        "Short Date Morning/Afternoon (" + 
                        DateTime.Now.ToString("d", 
                        Application.CurrentCulture) + " " + 
                        AMPM + ")";
                    this.CustomFormat = "MM-dd-yyyy HH:mm:ss";
                    break;
            }
            Tooltip.SetToolTip(txtDateTime, mvarCustomFormatMessage);
        }

        //Dispplay dates Times etc, based on Format selected
        private void FormatTextBox()
        {

            switch (mvarFormatEx)
            {
                case dtpCustomExtensions.dtpCustom:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = 
                           this.Value.ToString(this.CustomFormat, 
                           Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpDayFullName:
                    try
                    {
                        this.Value = DateTime.Parse(txtDateTime.Text);
                    }
                    catch
                    {
                        int aDay;
                        DateTime aDate;
                        for (aDay = 1; aDay < 8; aDay++)
                        {
                            aDate = DateTime.Parse
                                    (DateTime.Now.Year.ToString() 
                                    + "-01-" + aDay.ToString());
                            if (aDate.DayOfWeek.ToString().ToLower() == 
                               txtDateTime.Text.ToLower() || 
                               aDate.DayOfWeek.ToString().
                               Substring(0, 3).ToLower() 
                               == txtDateTime.Text.ToLower())
                            {
                                this.Value = DateTime.Parse
                                  (DateTime.Now.Year.ToString() + 
                                  "-01-" + aDay.ToString());
                                break;
                            }
                        }
                    }
                    txtDateTime.Text = this.Value.ToString("dddd", 
                                       Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpDayShortName:
                    try
                    {
                        this.Value = DateTime.Parse(txtDateTime.Text);
                    }
                    catch
                    {
                        int aDay;
                        DateTime aDate;
                        for (aDay = 1; aDay < 8; aDay++)
                        {
                            aDate = DateTime.Parse
                             (DateTime.Now.Year.ToString() + 
                             "-01-" + aDay.ToString());
                            if (aDate.DayOfWeek.ToString().ToLower() 
                              == txtDateTime.Text.ToLower() || 
                              aDate.DayOfWeek.ToString().Substring(0, 3).
                              ToLower() == txtDateTime.Text.ToLower())
                            {
                                this.Value = DateTime.Parse
                                  (DateTime.Now.Year.ToString() + 
                                  "-01-" + aDay.ToString());
                                break;
                            }
                        }
                    }
                    txtDateTime.Text = this.Value.ToString("ddd", 
                               Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpLongDateLongTime24Hour:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToString("D", 
                              Application.CurrentCulture) + " " + 
                              this.Value.ToString("HH:mm:ss", 
                              Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpLongDateLongTimeAMPM:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToString("D", 
                              Application.CurrentCulture) + " " + 
                              this.Value.ToString("hh:mm:ss tt", 
                              Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpLongDateShortTime24Hour:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToString("D", 
                              Application.CurrentCulture) + " " + 
                              this.Value.ToString("HH:mm", 
                              Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpLongDateShortTimeAMPM:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToString("D", 
                              Application.CurrentCulture) + " " + 
                              this.Value.ToString("hh:mm tt", 
                              Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpLongTime24Hour:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToString("HH:mm:ss", 
                              Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpMonthFullName:
                    try
                    {
                        this.Value = DateTime.Parse(txtDateTime.Text);
                    }
                    catch
                    {
                        int aMonth;
                        DateTime aDate;
                        string[] sMonth = new string[]{"Jan","Feb",
                                "Mar","Apr","May","Jun","Jul","Aug",
                                "Sep","Oct","Nov","Dec"}; 
                        for (aMonth = 0; aMonth < 12; aMonth++)
                        {
                            aDate = DateTime.Parse
                                 (DateTime.Now.Year.ToString() + 
                                 "-" + (aMonth + 1) + "-" + "01");
                            if (sMonth[aMonth].ToLower() == 
                               txtDateTime.Text.ToLower() || 
                               sMonth[aMonth].ToLower() == 
                               txtDateTime.Text.Substring(0, 3).ToLower())
                            {
                                this.Value = DateTime.Parse
                                  (DateTime.Now.Year.ToString() 
                                  + "-"+ (aMonth + 1) + "-" + "01");
                                break;
                            }
                        }
                    }
                    txtDateTime.Text = this.Value.ToString("MMMM", 
                                        Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpMonthShortName:
                    try
                    {
                        this.Value = DateTime.Parse(txtDateTime.Text);
                    }
                    catch
                    {
                        int aMonth;
                        DateTime aDate;
                        string[] sMonth = new string[]{"Jan",
                          "Feb","Mar","Apr","May","Jun","Jul",
                          "Aug","Sep","Oct","Nov","Dec"}; 
                        for (aMonth = 0; aMonth < 12; aMonth++)
                        {
                            aDate = DateTime.Parse
                               (DateTime.Now.Year.ToString() + 
                               "-" + (aMonth + 1) + "-" +  "01");
                            if (sMonth[aMonth].ToLower() == 
                               txtDateTime.Text.ToLower() || 
                               sMonth[aMonth].ToLower() == 
                               txtDateTime.Text.Substring(0, 3).ToLower())
                            {
                                this.Value = DateTime.Parse
                                   (DateTime.Now.Year.ToString() + 
                                   "-"+ (aMonth + 1) + "-" + "01");
                                break;
                            }
                        }
                    }
                    txtDateTime.Text = this.Value.ToString("MMM", 
                           Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpMonthNameAndDay:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToString("M", 
                           Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpShortDateLongTime24Hour:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToString("d", 
                           Application.CurrentCulture) + " " + 
                           this.Value.ToString("HH:mms:ss", 
                           Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpShortDateLongTimeAMPM:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToString("d", 
                           Application.CurrentCulture) + " " + 
                           this.Value.ToString("hh:mms:ss tt", 
                           Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpShortDateShortTime24Hour:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToString("d", 
                           Application.CurrentCulture) + " " + 
                           this.Value.ToString("HH:mm", 
                           Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpShortDateShortTimeAMPM:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToString("d", 
                           Application.CurrentCulture) + " " + 
                           this.Value.ToString("hh:mms tt", 
                           Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpShortTime24Hour:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToString("HH:mm", 
                           Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpShortTimeAMPM:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToString("hh:mm tt", 
                           Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpSortableDateAndTimeLocalTime:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToString("s", 
                           Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpUTFLocalDateAndLongTime24Hour:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToString("yyyy-MM-dd", 
                           Application.CurrentCulture) + " " + 
                           this.Value.ToString("HH:mm:ss", 
                           Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpUTFLocalDateAndLongTimeAMPM:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToString("yyyy-MM-dd", 
                            Application.CurrentCulture) + " " + 
                            this.Value.ToString("hh:mm:ss tt", 
                            Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpUTFLocalDateAndShortTime24Hour:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToString("yyyy-MM-dd", 
                            Application.CurrentCulture) + " " + 
                            this.Value.ToString("HH:mm", 
                            Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpUTFLocalDateAndShortTimeAMPM:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToString("yyyy-MM-dd", 
                            Application.CurrentCulture) + " " + 
                            this.Value.ToString("hh:mm tt", 
                            Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpYear4Digit:
                    try
                    {
                        this.Value = DateTime.Parse(txtDateTime.Text);
                    }
                    catch
                    {
                        this.Value = DateTime.Parse("01 01 " + 
                                               txtDateTime.Text);
                    } 
                    txtDateTime.Text = this.Value.ToString("yyyy", 
                                      Application.CurrentCulture);
                    break;
                case dtpCustomExtensions.dtpYearAndMonthName:
                    try
                    {
                        this.Value = DateTime.Parse(txtDateTime.Text);
                    }
                    catch
                    {
                        try
                        {
                            txtDateTime.Text = 
                              DateTime.Now.Year.ToString() + " " + 
                              int.Parse(txtDateTime.Text, 
                              Application.CurrentCulture).ToString();
                        }
                        catch
                        {
                            this.Value = 
                                DateTime.Parse(txtDateTime.Text + 
                                " 01" );
                        }
                    }
                    txtDateTime.Text = this.Value.ToString("Y", 
                                    Application.CurrentCulture);
                    break;
                case  dtpCustomExtensions.dtpShortDateAMPM:
                    if (txtDateTime.Text.Substring
                        (txtDateTime.Text.Length - 2, 2).ToLower() 
                        == "pm")
                    {
                        txtDateTime.Text = 
                          txtDateTime.Text.Substring(0, 
                          txtDateTime.Text.Length - 2);
                        txtDateTime.Text = txtDateTime.Text + 
                          " 13:00";
                    }
                    else
                    {
                        if (txtDateTime.Text.Substring
                         (txtDateTime.Text.Length - 2, 2).
                          ToLower() == "am")
                        {
                            txtDateTime.Text = 
                               txtDateTime.Text.Substring(0, 
                               txtDateTime.Text.Length - 2);
                        }
                        txtDateTime.Text = txtDateTime.Text + " 01:00";
                    }
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToString("d", 
                            Application.CurrentCulture) + " " + 
                            this.Value.ToString("tt", 
                            Application.CurrentCulture);
                    break;
                case  dtpCustomExtensions.dtpShortDateMorningAfternoon:
                    string AMPM = "Morning";
                    if (txtDateTime.Text.Substring
                         (txtDateTime.Text.Length - 2, 2).
                         ToLower() == "pm")
                    {
                        txtDateTime.Text = 
                             txtDateTime.Text.Substring(0, 
                             txtDateTime.Text.Length - 2);
                        txtDateTime.Text = txtDateTime.Text + " 13:00";
                    }
                    else
                    {
                        if (txtDateTime.Text.Substring
                             (txtDateTime.Text.Length - 2, 2).
                             ToLower() == "am")
                        {
                            txtDateTime.Text = 
                               txtDateTime.Text.Substring(0, 
                               txtDateTime.Text.Length - 2);
                        }
                        txtDateTime.Text = txtDateTime.Text + " 01:00";
                    }
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    if (this.Value.Hour >= 12)
                    {
                        AMPM = "Afternoon";
                    }
                    txtDateTime.Text = this.Value.ToString("d", 
                            Application.CurrentCulture) + " " + AMPM;
                    break;
                case dtpCustomExtensions.dtpLong:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToLongDateString();
                    break;
                case dtpCustomExtensions.dtpShort:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToShortDateString();
                    break;
                case dtpCustomExtensions.dtpTime:
                    this.Value = DateTime.Parse(txtDateTime.Text);
                    txtDateTime.Text = this.Value.ToLongTimeString();
                    break;
                default:
                    break;
            }
        }

        #endregion

    }
}

Points of interest

As the code stands, it is only really useful in English speaking locations. While the control will accept dates and or times in any format that is valid for the current location, and display those dates and time correctly, based on the Format selected in FormatEx, all of the messages are in English.