Error - System.InvalidOperationException: RegisterForEventValidation can only be called during Render();

Question

User-1499457942 posted

Hi

  I have below code in Content Page but it is giving above error

Response.Clear();  
           Response.Buffer = true;  
           Response.ClearContent();  
           Response.ClearHeaders();  
           Response.Charset = "";  
           string FileName ="Vithal"+DateTime.Now+".xls";  
           StringWriter strwritter = new StringWriter();  
           HtmlTextWriter htmltextwrtter = new HtmlTextWriter(strwritter);        
           Response.Cache.SetCacheability(HttpCacheability.NoCache);  
           Response.ContentType ="application/vnd.ms-excel";    
           Response.AddHeader("Content-Disposition","attachment;filename=" + FileName);
           gvw.GridLines = GridLines.Both;
           gvw.HeaderStyle.Font.Bold = true;
           gvw.RenderControl(htmltextwrtter);  
           Response.Write(strwritter.ToString());  
           Response.End();      

Thanks

Answer 1

User475983607 posted

You can just take a few moments to Google a solution...

https://www.google.com/search?q=RegisterForEventValidation+can+only+be+called+during+Render()&rlz=1C1GGRV_enUS812US812&oq=RegisterForEventValidation+can+only+be+called+during+Render()&aqs=chrome..69i57j69i60j0l4.571j0j7&sourceid=chrome&ie=UTF-8

Answer 2

User1724605321 posted

Hi JagjitSingh ,

Please try to override VerifyRenderingInServerForm by adding following method in your C# code behind :

        public override void VerifyRenderingInServerForm(Control control)
        {
            /* Confirms that an HtmlForm control is rendered for the specified ASP.NET
               server control at run time. */
        }

Best Regards,

Nan Yu