GridView must be placed inside a form tag with runat server even after the GridView is within a form tag

Question

lt form runat  server  id  f1  gt       lt div runat  server  id  d  gt          grid view           lt asp GridView runat  server  ID  g  gt           lt  asp GridView gt       lt  div gt        lt asp TextBox runat  server  ID  t  TextMode  MultiLine  Rows  20  Columns  50  gt  lt  asp TextBox gt   lt  form gt    Code behind   public partial class ScriptTest   System Web UI Page       protected void Page Load object sender  EventArgs e                g DataSource   new string      a    b    c             g DataBind             TextWriter tw   new StringWriter            HtmlTextWriter h   new HtmlTextWriter tw               d RenderControl h           t Text   tw ToString              Even the GridView is within a from tag with runat  server   still I am getting this error   Any clues please

User · Answer

Here is My Code  protected void btnExcel Click object sender  ImageClickEventArgs e                if  gvDetail Rows Count  gt  0                        System IO StringWriter stringWrite1   new System IO StringWriter                System Web UI HtmlTextWriter htmlWrite1   new HtmlTextWriter stringWrite1               gvDetail RenderControl htmlWrite1                gvDetail AllowPaging   false              Search                sh ExportToExcel gvDetail   Report                         public override void VerifyRenderingInServerForm Control control                   Confirms that an HtmlForm control is rendered for the specified ASP NET            server control at run time

User · Answer

You are calling GridView RenderControl htmlTextWriter   hence the page raises an exception that a Server-Control was rendered outside of a Form    You could avoid this execption by overriding VerifyRenderingInServerForm  public override void VerifyRenderingInServerForm Control control         Confirms that an HtmlForm control is rendered for the specified ASP NET      server control at run time         See here and here

User · Answer

An alternative to overriding VerifyRenderingInServerForm is to remove the grid from the controls collection while you do the render  and then add it back when you are finished before the page loads  This is helpful if you want to have some generic helper method to get grid html because you don t have to remember to add the override   Control parent   grid Parent  int GridIndex   0  if  parent    null        GridIndex   parent Controls IndexOf grid       parent Controls Remove grid      grid RenderControl hw    if  parent    null        parent Controls AddAt GridIndex  grid       Another alternative to avoid the override is to do this   grid RenderBeginTag hw   grid HeaderRow RenderControl hw   foreach  GridViewRow row in grid Rows        row RenderControl hw     grid FooterRow RenderControl hw   grid RenderEndTag hw

User · Answer

Just after your Page Load add this   public override void VerifyRenderingInServerForm Control control          base VerifyRenderingInServerForm control       Note that I don t do anything in the function   EDIT  Tim answered the same thing     You can also find the answer Here

User · Answer

Just want to add another way of doing this  I ve seen multiple people on various related threads ask if you can use VerifyRenderingInServerForm without adding it to the parent page   You actually can do this but it s a bit of a bodge   First off create a new Page class which looks something like the following   public partial class NoRenderPage   System Web UI Page       protected void Page Load object sender  EventArgs e               public override void VerifyRenderingInServerForm Control control                  Allows for printing            public override bool EnableEventValidation               get   return false            set     Do nothing               Does not need to have an  ASPX associated with it   Then in the control you wish to render you can do something like the following       StringWriter tw   new StringWriter        HtmlTextWriter hw   new HtmlTextWriter tw        var page   new NoRenderPage        page DesignerInitialize        var form   new HtmlForm        page Controls Add form       form Controls Add pnl       controlToRender RenderControl hw     Now you ve got your original control rendered as HTML  If you need to  add the control back into it s original position  You now have the HTML rendered  the page as normal and no changes to the page itself

[c#] GridView must be placed inside a form tag with runat="server" even after the GridView is within a form tag

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