If you try to change the TextMode property of ASP.NET TextBox control to Multiline and set the MaxLength property it’ll not work and user can insert as much characters as he/she want. WHY? Because when you put TextBox in your WebForm it’ll be rendered to HTML <input> tag but when you set the TextMode to multiline it’ll be rendered to <textarea> tag, and MaxLength attribute is in <input> but it’s not for <textarea>.
So dude How can I solve this issue?
As you can see in line number 2 I pass TextBox and MaxLength, this will make the max number of characters user can input in the MultiLine TextBox is 15.