How to validate textbox containing website, email information

It's simple first set the Causevalidation proeprty to true then implement the textBox_Validating(.....)  event handler
dont forget to include System.Text.RegualrExpressions namespace
public textBox_Validating(object sender, eventarg e)
{
     if(Check(textbox.text))
     {
               instruction1;
     }
     else
     {
           instruction 2;
     }
}
public bool Check(string input)
        {
            bool response = false;
            if(Regex.IsMatch(input,@"\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*"))
            {response = true;}
            else { response = false; }
            return response;

        }