Asp.net Web Forms GridView Dynamic Column Issue

Question

We have a .Net Web Form application with 4.7.2 version. When we insert column programmaticaly to GridView component, TemplateFields not rendering after postback. We found a topic about that issue. I think this is a .Net framework bug. There is a feedback url on the post but I couldn't open that page.

FeedBack url:

https://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=104994&wa=wsignin1.0

Topic url:

https://forums.asp.net/t/1102255.aspx?GridView+Columns+Insert+Problems

Example Code:

Aspx ->

 <asp:Content ID="BodyContent" ContentPlaceHolderID="MainContent" runat="server">
   <asp:GridView ID="TestGrid" runat="server" AutoGenerateColumns="false">
       <Columns>
           <asp:BoundField HeaderText="Col1" DataField="Name" />
           <asp:TemplateField>
               <HeaderTemplate>
                   <asp:Label ID="Col2HeaderLabel" runat="server" Text="Col2"></asp:Label>
               </HeaderTemplate>
               <ItemTemplate>
                   <asp:CheckBox ID="Col2CheckBox" runat="server" />
               </ItemTemplate>
           </asp:TemplateField>
           <asp:BoundField HeaderText="Col3" DataField="Surname" />
       </Columns>
   </asp:GridView>

    <asp:Button ID="TestButton" runat="server" Text="Test" />
</asp:Content>

Aspx.cs ->

        protected override void OnInit(EventArgs e)
        {
            base.OnInit(e);

            TestGrid.Columns.Insert(0,new BoundField { HeaderText = "Dynamic Col", DataField = "Description" });
        }

        protected void Page_Load(object sender, EventArgs e)
        {
            TestGrid.DataSource = GetList();
            TestGrid.DataBind();
        }

        private List<Info> GetList()
        {
            List<Info> list = new List<Info>();
            list.Add(new Info { Description = "Row 1", Name = "Name 1", Surname = "Surname 1" });
            list.Add(new Info { Description = "Row 2", Name = "Name 2", Surname = "Surname 2" });
            list.Add(new Info { Description = "Row 3", Name = "Name 3", Surname = "Surname 3" });

            return list;
        }
    }

    public class Info
    {
        public string Name { get; set; }
        public string Surname { get; set; }
        public string Description { get; set; }
    }

It would be helpful to post some of your code so we can figure out your specific issue. — JohnPete22
– JohnPete22, Commented Aug 21, 2020 at 14:44
You will need to recreate those dynamic columns in the OnInit of the page/user control and then rebind the data to them. — Salik Rafiq
– Salik Rafiq, Commented Aug 21, 2020 at 17:55

Jamal · Accepted Answer · 2020-08-21 17:53:15Z

1

@yusuf, you need to re-bind the datasource to the GridView on PostBack. Save the data gridView.DataSource into a Session variable and on PostBack do the bind again. This will ensure binding is not lost.

protected void Page_Load(object sender, EventArgs e)
{
if (Session["gvDS"] != null && IsPostBack)
    {
        gridView1.DataSource = Session["gvDS"];
        gridView1.DataBind();
    }
    else
        BindGridView();


}

private void BindGridView()
{
  // Your SQL statements go here, etc, then:

  gridView1.DataSource = YourDataSetTable;
  gridView1.DataBind();

  Session["gvDS"] = gridView1.DataSource;  // save into Session

}

answered Aug 21, 2020 at 17:53

Jamal

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