Hi,

I have solve this problem and it is working properly with validation controls like Rangevalidation, RegularExpressionValidator and RequiredFieldValidator

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace IFS2.BackOffice.Web.Common
{
[DefaultProperty("Text")]
[ToolboxData("<{0}:RequiredTextBox1 runat=server>")]
public class RequiredTextBox1 : TextBox
{
private RequiredFieldValidator req;
private RegularExpressionValidator reqExpress;
private RangeValidator RangeVldtr;
public string InvalidMessage;
public string ClientScript = "true";

[Bindable(true)]
[Category("Appearance")]
[DefaultValue("")]
[Localizable(true)]
public string RequiredErrMsg
{
get
{
String s = (String)ViewState["RequiredErrMsg"];
return ((s == null) ? "This Field is Mandatory " : s);
}

set
{
ViewState["RequiredErrMsg"] = value;
}
}

public enum YesNo : int
{
True=0,
False=1
}

[Bindable(true)]
[Category("Appearance")]
[DefaultValue("")]
[Localizable(true)]
[EditorBrowsable(EditorBrowsableState.Always)]
public bool RequiredField
{
get
{
object o = ViewState["RequiredField"];
if (o == null)
return false;
return (bool)o;
}

set
{
ViewState["RequiredField"] = value;
}
}


[Bindable(true)]
[Category("Appearance")]
[DefaultValue("")]
[Localizable(true)]
[EditorBrowsable(EditorBrowsableState.Always)]
public bool RangevalidationField
{
get
{
object o = ViewState["RangevalidationField"];
if (o == null)
return false;
return (bool)o;
}

set
{
ViewState["RangevalidationField"] = value;
}
}

[Bindable(true)]
[Category("Appearance")]
[DefaultValue("")]
[Localizable(true)]
[EditorBrowsable(EditorBrowsableState.Always)]
public string RangevalidationMaxVal
{
get
{
string o = (string) ViewState["RangevalidationMaxVal"];
if (o == null)
return string.Empty;
return o;
}

set
{
ViewState["RangevalidationMaxVal"] = value;
}
}

[Bindable(true)]
[Category("Appearance")]
[DefaultValue("")]
[Localizable(true)]
[EditorBrowsable(EditorBrowsableState.Always)]
public string RangevalidationMinVal
{
get
{
string o = (string)ViewState["RangevalidationMinVal"];
if (o == null)
return string.Empty;
return o;
}

set
{
ViewState["RangevalidationMinVal"] = value;
}
}

[Bindable(true)]
[Category("Appearance")]
[DefaultValue("")]
[Localizable(true)]
[EditorBrowsable(EditorBrowsableState.Always)]
public string FieldLength
{
get
{
string o = (string)ViewState["FieldLength"];
if (o == null)
return string.Empty;
return o;
}

set
{
ViewState["FieldLength"] = value;
}
}



[Bindable(true)]
[Category("Appearance")]
[DefaultValue("")]
[Localizable(true)]
[EditorBrowsable(EditorBrowsableState.Always)]
public string RangevalidationType
{
get
{
string o = (string)ViewState["RangevalidationType"];
if (o == null)
return string.Empty;
return o;
}

set
{
ViewState["RangevalidationType"] = value;
}
}


//[Bindable(true)]
//[Category("Appearance")]
//[DefaultValue("")]
//[Localizable(true)]
//public String ID {
// get
// {
// String s = (String)ViewState["ID"];
// return ((s == null) ? ClientID.ToString() : s);
// }
// set
// {
// ViewState["ID"] = value;
// }

//}


protected override void OnInit(EventArgs e)
{
if (Context != null)
{

req = new RequiredFieldValidator();

if (this.ID == null)
{
this.ID = "RequiredTextBox1" + GetNumbers(ClientID).ToString();
}

RangeVldtr = new RangeValidator();
reqExpress = new RegularExpressionValidator();

//reqExpress.ValidationExpression= "^[0-9]*$"; //only for Number not letter and space
//reqExpress.ValidationExpression = "^[a-zA-Z''-'\\s]{1,40}$"; //only for Strings 1 for min character and 40 for maximum charactor

if (RangevalidationType == string.Empty)
{
reqExpress.ValidationExpression = "";
}

if (RangevalidationType != string.Empty)
{
string Req_exprMsg="";
switch (RangevalidationType)
{
case "Decimal":
case "Integer":
case "Numeric":
{
if (FieldLength != string.Empty)
{

reqExpress.ValidationExpression = "^\\d{1" + "," + FieldLength + "}$";
Req_exprMsg = "Required maximum charactor length is " + FieldLength;
}
if (FieldLength == string.Empty && RangevalidationMaxVal == string.Empty && RangevalidationMinVal ==string.Empty )
{

reqExpress.ValidationExpression = "^\\d+$";
Req_exprMsg = "Please enter the " + RangevalidationType + " value";
}


//else
//{
// reqExpress.ValidationExpression = "^\\d+$";
// Req_exprMsg = "Please enter the " + RangevalidationType + " value";
//}
}
break;
//case "Decimal":
// {
// reqExpress.ValidationExpression = "";
// Req_exprMsg = "Please enter the decimal value";
// }
// break;
case "String":
case "Text":
{
// reqExpress.ValidationExpression = "^[a-zA-Z''-'\\s]{1,40}$";
//Req_exprMsg = "Please enter the value";

if (FieldLength != string.Empty)
{
reqExpress.ValidationExpression = "^[a-zA-Z''-'\\s]{0" + "," + FieldLength + "}$";
Req_exprMsg = "Field validation length is " + FieldLength;
}
if (FieldLength == string.Empty && RangevalidationMaxVal == string.Empty && RangevalidationMinVal == string.Empty)
{
reqExpress.ValidationExpression = "^[a-zA-Z''-'\\s]$";
Req_exprMsg = "Please enter the Text value";
}
}
break;
//case "Numeric":
// {
// if (RangevalidationMinVal != string.Empty && RangevalidationMaxVal != string.Empty)
// {
// reqExpress.ValidationExpression = "^\\d[0-9]{" + RangevalidationMinVal + "," + RangevalidationMaxVal + "}*$";
// Req_exprMsg = "Please enter the Numeric value between the " + RangevalidationMinVal + " to " + RangevalidationMaxVal;
// }
// else
// {
// reqExpress.ValidationExpression = "^\\d[0-9]*$";
// Req_exprMsg = "Please enter the Numeric value";
// }
// }
//break;
case "IPAddres":
{
reqExpress.ValidationExpression = "";
Req_exprMsg = "Please enter the IP Address";
}
break;
case "E-mail":
{
reqExpress.ValidationExpression = @"^(?("")("".+?(?
Req_exprMsg = "Please enter the valid Emil Address";
}
break;
default:
reqExpress.ValidationExpression = "";
Req_exprMsg = "Please enter the value";
break;
}

reqExpress.ControlToValidate = this.ID;
reqExpress.ErrorMessage = "
" + Req_exprMsg;
reqExpress.ForeColor = System.Drawing.Color.Red;
Controls.Add(reqExpress);
}

//for RangeVldtr

if (RangevalidationType != string.Empty && RangevalidationMaxVal != string.Empty && RangevalidationMinVal != string.Empty )
{
string Range_exprMsg = "enter the value of " + RangevalidationType + " and range between " + RangevalidationMinVal + " to " + RangevalidationMaxVal;

RangeVldtr.ControlToValidate = this.ID;
RangeVldtr.MinimumValue = RangevalidationMinVal;
RangeVldtr.MaximumValue = RangevalidationMaxVal;
RangeVldtr.ErrorMessage = "
" + Range_exprMsg;
RangeVldtr.ForeColor = System.Drawing.Color.Red;
Controls.Add(RangeVldtr);
}

// for phone number "^[01]?[- .]?(\([2-9]\d{2}\)|[2-9]\d{2})[- .]?\d{3}[- .]?\d{4}$"
//social security Name "^\d{3}-\d{2}-\d{4}$" like "111-111-1111"

if (RequiredField.ToString().ToLower() == "true")
{
req.ControlToValidate = this.ID;
req.ErrorMessage = "
" + RequiredErrMsg;
req.ForeColor = System.Drawing.Color.Red;
req.EnableClientScript = (this.ClientScript.ToLower() != "false");
Controls.Add(req);
}
}
}

//protected override void Render(HtmlTextWriter w)
//{
// base.Render(w);
// req.RenderControl(w);

//}

//protected override void OnPreRender(EventArgs e)
//{
// StringWriter sb = new StringWriter();
// HtmlTextWriter output = new HtmlTextWriter(sb);

// base.OnPreRender(e);
// //base.RenderControl(output);
//}

protected override void Render(HtmlTextWriter writer)
{
if (Context != null)
{
base.Render(writer);

//this.RenderContents(writer);
//req.RenderControl(writer);
this.RenderContents(writer);
}
}

//protected override void RenderContents(HtmlTextWriter writer)
//{

// // render event run 1st and then run the rendercontents event
// //base.Render(writer);
// //req.RenderControl(writer);

// base.Render(writer);
// req.RenderControl(writer);
// //Render(writer);
// //writer.Write("

hello

");
//}


protected string GetNumbers(string input)
{
return new string(input.Where(c => char.IsDigit(c)).ToArray());
}

}
}