Question

I realized that ShowHeaderWhenEmpty only works in PostBacks. Is there any way to make it work once the page is loaded?

<asp:GridView ID="GridView1"... ShowHeaderWhenEmpty="true"... >
<EmptyDataTemplate>
<asp:Label ID="Label1" runat="server" Text="No records found"></asp:Label>
</EmptyDataTemplate>

When I have no info to show, the above message only appears in PostBacks, no when the page is loaded.

Answer 1

Note: This answer assumes (based on your question) you are binding your GridView to a data source on PostBack, and not at all during Page_Load. Please correct me if I’m wrong.

The <EmptyDataTemplate> content only shows once your GridView has been databound. If you are only databinding on Postback (based on some user interaction) one way to solve this problem would be to bind your GridView to an empty (artificial) dataset, just so the <EmptyDataTemplate> will show.

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    If Not IsPostBack
        Dim table As New DataTable
        GridView1.DataSource = table
        GridView1.DataBind()
    End If
End Sub

From the MSDN article on the EmptyDataTemplate (emphasis mine):

The empty data row is displayed in a GridView control when the data
source that is bound to the control does not contain any records.

If there is no datasource bound to the control, this property is not yet relevant.