Text Box Control with built in Data validation

/* --------------------------------------------------------------------------------------
 * Module.....:	TextControl
 * Created on.:	10/15/07
 * Created by.:	Balamurugan R A. 
 * Desc.......:	Common Text Control to perform routine validations
 * --------------------------------------------------------------------------------------
 */
using System;
using System.Data;
using System.Configuration;
using System.Text.RegularExpressions;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;



namespace SS.Web.UI.Controls
{
    
    public class TextControl : CompositeControl, INamingContainer
    {
        #region variable declaration

        private string __labelCaption = string.Empty;
        private string __regEx = string.Empty;
        private string __regExErrMsg = "Please enter only Alpha Numerals";

        private bool __reqd = false;
        private int __maxLength;
        private bool __validate = false;
        private string __reqdErrMsg = "This field Cant be Empty";
        private string __validationGroup = string.Empty;
        private string __textValue = string.Empty;

        protected Label lblCaption = new Label();
        protected TextBox txtInput = new TextBox();
        protected CustomValidator cvCustomVal = new CustomValidator();
        protected RequiredFieldValidator regVal = new RequiredFieldValidator();

        #endregion

        #region custom validation event
        public event CustomValidationHandler ValidateEvent;

        protected virtual void OnValidateEvent(ServerValidateEventArgs args)
        {
            if (ValidateEvent != null)
            {
                ValidateEvent(this, args);
            }
        }
        #endregion

        #region properties

        public string Text
        {
            get
            {
                this.EnsureChildControls();
                TextBox txt = this.FindControl(this.ID + "_text1") as TextBox;
                if (txt != null)
                {
                    return txt.Text;

                }
                else
                    return string.Empty;

            }
            set
            {
                this.EnsureChildControls();
                TextBox txt = this.FindControl(this.ID + "_text1") as TextBox;
                if (txt != null)
                {
                    txt.Text = value;
                    __textValue = value;
                }

            }
        }

        public string Caption
        {
            get
            {
                this.EnsureChildControls();
                return __labelCaption;
            }
            set
            {
                this.EnsureChildControls();
                __labelCaption = value;
            }
        }

        public string RegEx
        {
            get
            {
                this.EnsureChildControls();
                return __regEx;
            }
            set
            {
                this.EnsureChildControls();
                __regEx = value;
            }
        }

        public string RegExErrorMessage
        {
            get
            {
                this.EnsureChildControls();
                return __regExErrMsg;
            }
            set
            {
                this.EnsureChildControls();
                __regExErrMsg = value;
            }
        }

        public string ValidationGroup
        {
            get
            {
                this.EnsureChildControls();
                return __validationGroup;
            }
            set
            {
                this.EnsureChildControls();
                __validationGroup = value;
            }
        }
        
        public bool Required
        {
            get
            {
                this.EnsureChildControls();
                return __reqd;
            }
            set
            {
                this.EnsureChildControls();
                __reqd = value;
            }
        }

        public bool Validate
        {
            get
            {
                this.EnsureChildControls();
                return __validate;
            }
            set
            {
                this.EnsureChildControls();
                __validate = value;
            }
        }

        public int MaxLength
        {
            get
            {
                this.EnsureChildControls();
                return __maxLength;
            }
            set
            {
                this.EnsureChildControls();
                __maxLength = value;
            }
        }

        public string RequiredErrorMessage
        {
            get
            {
                this.EnsureChildControls();
                return __reqdErrMsg;
            }
            set
            {
                this.EnsureChildControls();
                __reqdErrMsg = value;
            }
        }

        #endregion
                
        #region overridden methods load, init and pre render
                protected override void OnLoad(EventArgs e)
                {
                    lblCaption.Text = Caption;

                    base.OnLoad(e);
                }

                protected override void OnInit(EventArgs e)
                {
                    if (!Required)
                        regVal.Visible = false;

                    if (MaxLength > 0)
                        txtInput.MaxLength = MaxLength;

                    if (!string.IsNullOrEmpty(ValidationGroup))
                    {
                        txtInput.ValidationGroup = ValidationGroup;
                        regVal.ValidationGroup = ValidationGroup;
                        cvCustomVal.ValidationGroup = ValidationGroup;
                    }

                    cvCustomVal.ServerValidate += new System.Web.UI.WebControls.ServerValidateEventHandler(this.validator_ServerValidate);

                    base.OnInit(e);
                }

                protected override void OnPreRender(EventArgs e)
                {
                    base.OnPreRender(e);
                }

        #endregion

        #region Child Controls
        protected override void CreateChildControls()
        {
            base.CreateChildControls();

            lblCaption.ID = this.ID + "_lblCaption";
            txtInput.ID = this.ID + "_text1";
            

            regVal.ID = this.ID + "_reqValidator";
            regVal.ControlToValidate = txtInput.ID;
            regVal.EnableClientScript = false;
            regVal.ErrorMessage = RequiredErrorMessage;
            regVal.Text = "!";
            

            cvCustomVal.ID = this.ID + "_Validator";
            cvCustomVal.ControlToValidate = txtInput.ID;
            cvCustomVal.EnableClientScript = false;
            cvCustomVal.ErrorMessage = RegExErrorMessage;
            cvCustomVal.Text = "!";
           

            Controls.Add(new LiteralControl("<tr><td>"));
            Controls.Add(lblCaption);
            Controls.Add(new LiteralControl("</td><td>"));
            Controls.Add(txtInput);
            Controls.Add(regVal);
            Controls.Add(cvCustomVal);
            Controls.Add(new LiteralControl("</td></tr>"));


        }
        #endregion

        #region validation Event

        protected void validator_ServerValidate(object source, ServerValidateEventArgs args)
        {
            if (ValidateEvent != null)
            {
                OnValidateEvent(args);
            }
            else
            {
                Regex reg = null;

                if (string.IsNullOrEmpty(RegEx))
                    reg = new Regex("^[A-Za-z0-9 ]+$");
                else
                    reg = new Regex(RegEx);

                if (Validate && !reg.IsMatch((args.Value)))
                {
                    args.IsValid = false;
                    cvCustomVal.ErrorMessage = RegExErrorMessage;

                }
            }

        }

        #endregion

        
    }
}