Unable to cast object of type 'System.Web.UI.HtmlControls.HtmlInputHidden' to type 'System.IConvertible'.

"Unable to cast object of type 'System.Web.UI.HtmlControls.HtmlInputHidden' to type 'System.IConvertible'."

protected void dgcategory_ItemDataBound(object sender, DataGridItemEventArgs e)
   {
       if (e.Item.ItemType == ListItemType.Header)
       {
           CheckBox chk = new CheckBox();
           chk = (CheckBox)e.Item.FindControl("chkHeader");
           chk.Attributes.Add("onclick", "javascript:return checkheader('chkHeader');");

           ImageButton imgtitle = new ImageButton();
           imgtitle = (ImageButton)e.Item.FindControl("imgasc");
           if (queryval.Value == "asc")
           {
               imgtitle.ImageUrl = "images/asc.png";
               imgtitle.ToolTip = "Ascending";
               imgtitle.AlternateText = "Ascending";
           }
           else
           {
               imgtitle.ImageUrl = "images/desc.png";
               imgtitle.ToolTip = "Descending";
               imgtitle.AlternateText = "Descending";
           }

           ImageButton imgtitle1 = new ImageButton();
           imgtitle1 = (ImageButton)e.Item.FindControl("imgasc1");
           if (queryval1.Value == "asc")
           {
               imgtitle1.ImageUrl = "images/asc.png";
               imgtitle1.ToolTip = "Ascending";
               imgtitle1.AlternateText = "Ascending";
           }
           else
           {
               imgtitle1.ImageUrl = "images/desc.png";
               imgtitle1.ToolTip = "Descending";
               imgtitle1.AlternateText = "Descending";
           }
       }
       if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
       {
           CheckBox chk = new CheckBox();
           chk = (CheckBox)e.Item.FindControl("chkDelete");
           chk.Attributes.Add("onclick", "javascript:return checkother('chkHeader');");

           if (Convert.ToBoolean((HtmlInputHidden)e.Item.FindControl("hiddisstatus")) == true)
           {
               ((LinkButton)e.Item.FindControl("disstatus")).Text = "Activate";
           }
           else
           {
               ((LinkButton)e.Item.FindControl("disstatus")).Text = "Deactivate";
           }
       }
   }