Question

I have a page with a button and a textbox, when a input “<string>” in the text box and then I press the button I got this error: A potentially dangerous Request.Form value was detected from the client (TextBox1=”“<string>”“).

Answer 1

This is a security feature of ASP.NET, which prevents a user to submit potentially dangerous code like script blocks.

You can disable this by setting the validateRequest attribute of the Page directive to false

 <%@ Page validateRequest="false" %>

or disable it in web.config:

<configuration>
    <system.web>
        <pages validateRequest="false" />
    </system.web>
</configuration>

But be careful! As I said, this is a security feature!

You can read more about it here: http://www.asp.net/learn/whitepapers/request-validation