Validación de formularios utilizando los eventos del teclado (Key Validator) aspx c#

Esta clase permitirá delimitar el tipo de validación que le queremos poner a nuestro text box.

public class KeyCodeValidator

{

    public const string Texto = " if(window.event.keyCode >= 65 && window.event.keyCode <= 90 || window.event.keyCode >= 97 && window.event.keyCode <=122 || window.event.keyCode == 32 || window.event.keyCode == 164 || window.event.keyCode == 165 || window.event.keyCode == 46|| window.event.keyCode >= 192 && window.event.keyCode <= 252) window.event.returnValue=true; else window.event.returnValue=false; ";

    public const string Fecha = " if((window.event.keyCode >= 48 && window.event.keyCode <= 57) || window.event.keyCode == 47) window.event.returnValue=true; else window.event.returnValue=false; ";

    public const string Mail = " if(window.event.keyCode >= 65 && window.event.keyCode <= 90 || window.event.keyCode >= 97 && window.event.keyCode <=122 || window.event.keyCode >=48 && window.event.keyCode <= 57 || window.event.keyCode == 64 || window.event.keyCode == 29 || window.event.keyCode == 45 || window.event.keyCode == 46 || window.event.keyCode == 95) window.event.returnValue=true; else window.event.returnValue=false; ";

    public const string Decimal = " if(window.event.keyCode >= 48 && window.event.keyCode <= 57 || window.event.keyCode == 46 || window.event.keyCode == 44 || window.event.keyCode == 45) window.event.returnValue=true; else window.event.returnValue=false; ";

    public const string AlfaNumerico = " if(window.event.keyCode >= 65 && window.event.keyCode <= 90 || window.event.keyCode >= 97 && key.keyCode <=122 || window.event.keyCode == 32 || window.event.keyCode == 164 || window.event.keyCode == 165 || window.event.keyCode == 46|| window.event.keyCode >= 192 && key.keyCode <= 252 || window.event.keyCode >= 48 && key.keyCode <= 57) window.event.returnValue=true; else window.event.returnValue=false; ";

    public const string Bloqueado = " window.event.returnValue=false;";

    public const string Numerico = " if(window.event.keyCode >= 48 && window.event.keyCode <= 57) window.event.returnValue=true; else window.event.returnValue=false;";

}

Asignarle la validacion al textbox.

En el load del aspx:

txtdsComentario.Attributes.Add("onkeyPress", KeyCodeValidator.Texto);

Con esta validación no dejara teclear las teclas que no estan permitidas.