Invalid postback or callback argument. Event validation is enabled using <pages enableEventValidation="true"/> in configuration or <%@ Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.
for the code below.. i got an error as above.. do someone here can please help me to get control of the button for the c# code..
<asp:Button ID="btn_add_respond" runat="server" Text= Go to the complete details ...