How to set fixed size to a Multi line Text Box in ASP.NET

While i was working on the Sending mail from asp.net application , i have taken the text box of mail body, with multi line property. But when it is shown in browser, its size is changing when we drag its end point. So in order to fix that problem, by browsing on net i have found the simple  CSS  to fix the size of multi line text box . To do this include the following code in your CSS file:

<style type="text/css">
    .textsize {
        resize: none;
    }
</style>

And you can use this style in your text box by adding CssClass="textsize" .