Special escape character in c#

Question

I have a textbox in my application, in this textbox, I want to perform a validation check. If user enter [, \\ .'] these characters, it should prompt message that invalid character. However, what I did is just the regex to check the characters, but it seems that C# have trouble recognize [\\'] these simple. Are there a ways to deal with these special characters?

Answer 1

I am assuming you are trying to keep only alpha-numeric and space characters. Add a keypress event like this

    private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
    {
       var regex = new Regex(@"[^a-zA-Z0-9\s]");
       if (regex.IsMatch(e.KeyChar.ToString()))
       {
          e.Handled = true;
       }
    }

Answer 2

Try this code

   private static readonly char[] SpecialChars = @"[,.']".ToCharArray();
   int indexOf = YourInputString.IndexOfAny(SpecialChars);
   if (indexOf != -1)
   {
             //Print Contains Invalid Character 

   }