ASP.NET Runtime Validators

Hi,

Try the following,

Adding ASP.NET validation at runtime[^]

http://stackoverflow.com/questions/9297822/setting-regularexpressionvalidator-validationexpression-at-runtime[^]

If the above is not working, try the below

1. Add a using statement to reference the System.Text.RegularExpressions namespace.

2. Add the following code in your textchange event,

Regex reg = new Regex(@"^[a-zA-Z'.]{1,40}$");
Response.Write(reg.IsMatch(txtName.Text));

// Static method:
if (!Regex.IsMatch(txtName.Text, 
                   @"^[a-zA-Z'.]{1,40}$"))
{
  // Name does not match schema
}