According to msdn in ASP.NET you can not use the MaxLength property textbox with multiline mode. But I needed in my current application. So I search google and other search engines and finally some solutions. I just compile all the solutions in a single post.
Solution No. 1 to
ASP.NET TextBox.MultiLine MaxLength

Add the following javascript

Function Count (text, length)


var MaxLength = new Number (long); / / Change number to your max length.

if (document.getElementById ('<%= textBox.ClientID %>'). value.length> MaxLength) {

text.value.substring text.value = (0, MaxLength);

alert ("Only" + length + "characters");


Where "textBox" is the ID text box asp.
Also add the following event in your textbox.

onkeyup = "javascript: Count (this, 200);" onChange = "javascript: Count (this, 200);"

The code will look like a textbox


Solution No. 2 to

ASP.NET TextBox.MultiLine MaxLength

Another way to achieve this is regular expressions. You can add the following regular expression to validate a text box in asp.