Unable to render Grid View

Question

I have grid view in my user control, and I am getting below error:

RegisterForEventValidation can only be called during Render();

I am using gv.RenderControl(htw);

My code is as below:

private void ExportToExcel(string strFileName, GridView gv)
    {
        Response.ClearContent();
        Response.AddHeader("content-disposition", "attachment; filename=" + strFileName);
        Response.ContentType = "application/excel";
        System.IO.StringWriter sw = new System.IO.StringWriter();
        HtmlTextWriter htw = new HtmlTextWriter(sw);
        gv.RenderControl(htw);
        Response.Write(sw.ToString());
        Response.End();
    }

And to avoid Server control was created outside form control exception I am using below code:

public override void VerifyRenderingInServerForm(Control control)
{
    /* Verifies that the control is rendered */
}

But I'm using all this code in a usercontrol, There isn't this method in the base class. What should I do, even I placed above in my page in which I place my user control, but still I am getting above error

Also note I am using masterpage in which I have form tagged already.

score 1 · Accepted Answer · answered Jul 14 '13 at 10:02

1

Setting EnableEventValidation in page directive to false solved my problem.

 <%@ Page ............ EnableEventValidation="false" %>

answered Jul 14 '13 at 10:02

Ubaid Ashraf

1,049
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score 0 · Answer 2 · answered Jul 11 '13 at 00:42

C#

StringWriter sw = new StringWriter();
HtmlTextWriter hw = new HtmlTextWriter(sw);
Page pg = new Page();
HtmlForm hf = new HtmlForm();

hf.Attributes.Add("runat", "server");
hf.Controls.Add(gv);

pg.EnableEventValidation = false;
pg.Controls.Add(hf);
pg.DesignerInitialize();
pg.RenderControl(hw);

Current.Response.Clear();
Current.Response.AddHeader("content-disposition", "attachment;filename=FileName.xls");
Current.Response.Charset = string.Empty;
Current.Response.ContentType = "application/vnd.xls";
Current.Response.Write(sw.ToString());
Current.Response.End();

VB.NET

Dim sw As New StringWriter
Dim hw As New HtmlTextWriter(sw)
Dim pg As New Page()
Dim hf As New HtmlForm()

hf.Attributes.Add("runat", "server")
hf.Controls.Add(gv)

pg.EnableEventValidation = False
pg.Controls.Add(hf)
pg.DesignerInitialize()
pg.RenderControl(hw)

Current.Response.Clear()
Current.Response.AddHeader("content-disposition", "attachment;filename=FileName.xls")
Current.Response.Charset = String.Empty
Current.Response.ContentType = "application/vnd.xls"
Current.Response.Write(sw.ToString())
Current.Response.End()

@ubaidashrafmasoody, Edited, sorry. Also, good tool: http://www.developerfusion.com/tools/convert/vb-to-csharp/ — Nikita Silverstruk, Jul 11 '13 at 00:47
RegisterForEventValidation can only be called during Render(); this errror I am getting now @nikita — Ubaid Ashraf, Jul 12 '13 at 10:25

Unable to render Grid View

2 Answers2