In this post I will explain how to solve the problem “A potentially dangerous Request.Form value was detected from the client in ASP.NET WebForms” using asp.net.
<form id="form1" runat="server">
Server Error in ‘/RichTextboxSample’ Application.
A potentially dangerous Request.Form value was detected from the client (remarks =”<html></html>”)
Description: Request Validation has detected a potentially dangerous client input value, and processing of the request has been aborted. This value may indicate an attempt to compromise the security of your application, such as a cross-site scripting attack. You can disable request validation by setting validateRequest=false in the Page directive or in the configuration section. However, it is strongly recommended that your application explicitly check all inputs in this case.
Exception Details: System.Web.HttpRequestValidationException: A potentially dangerous Request.Form value was detected from the client (remarks="<html></html>5678,<c…").
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" ValidateRequest="false" %>