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Custom Control: Numeric TextBox: TextBox that alow you to enter only numbers

, 29 Jan 2007
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Sometimes we need to control the user input to some specific values. The following article explain how to do this with a TextBox
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Introduction

Sometimes we need to control the user input. This control is a normal TextBox, with the property that the control accept only numeric values!

because this control is a TextBox, we inherit from the base class like this NumericTextBox : TextBox

What we have to do is to override the events OnKeyPress and OnKeyDown for the control. The full code is this:


using System.Windows.Forms;
using System.ComponentModel;

namespace MyCustomControls
{
    [Description("Numeric TextBox")]
    public class NumericTextBox : TextBox
    {
        private bool nonNumberEntered = false;

        public NumericTextBox()
        {
            this.Width = 150;
        }

        protected override void OnKeyPress(KeyPressEventArgs e)
        {
            if (nonNumberEntered == true)
            {
                e.Handled = true;
            }
        }
        protected override void OnKeyDown(KeyEventArgs e)
        {
            nonNumberEntered = false;
            if (e.Shift == true || e.Alt == true)
            {
                nonNumberEntered = true;
                return;
            }
            if (e.KeyCode < Keys.D0 || e.KeyCode > Keys.D9)
            {
                if (e.KeyCode < Keys.NumPad0 || e.KeyCode > Keys.NumPad9)
                {
                    if (e.KeyCode != Keys.Back)
                    {
                        nonNumberEntered = true;
                    }
                }
            }
        }
    }
}



Now, all we have to do is to use it in our application.
This code can be improved. Now it's possible to Paste from clipboard non numeric values. Next version (I'll write this in few days) will contain this improvements!

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About the Author

zeltera
Engineer
Israel Israel
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Comments and Discussions

 
GeneralMy vote of 1 PinmemberAhmed_Said11-Jan-12 10:45 
QuestionPerfect solution Numeric TextBox PinmemberAsif Rehman11-Sep-11 23:08 
GeneralThis is better than your Article PinmemberEhsan Golkar28-Sep-08 2:26 
GeneralNumeric Up/Down Pinmembersabrown10018-Oct-07 7:24 
QuestionMSDN?? Pinmemberjubjubjub18-Aug-07 6:13 
GeneralMasked Edit PinmvpMark Nischalke29-Jan-07 7:06 
GeneralKeyDown not needed [modified] PinmemberLuc Pattyn29-Jan-07 6:54 
GeneralRe: KeyDown not needed PinmemberLimitedAtonement2-Nov-09 7:44 
GeneralUseful PinmemberIlíon29-Jan-07 4:25 
GeneralRe: Useful Pinmemberzeltera29-Jan-07 4:32 
GeneralRe: Useful PinmemberIlíon29-Jan-07 5:33 

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