Formview.ChangeMode is not working - asp.net

Question

This is my webpage:
<asp:FormView
ID = "frmView1"
DefaultMode = "Insert"
runat = "server"
>
<ItemTemplate>
Item Template
</ItemTemplate>
<InsertItemTemplate>
Insert Item Template
</InsertItemTemplate>
</asp:FormView>
<asp:Button ID="btnSubmit" Text="Submit" runat="server" />
and this is the code-behind:
Private Sub btnSubmit_Click(sender As Object, e As System.EventArgs) Handles btnSubmit.Click
frmView1.ChangeMode(FormViewMode.ReadOnly)
End Sub
When I'm clicking the btnSubmit the formview is not showing anything! Is this the right way to change mode in code behind?
Moreover, in code behind instead of ChangeMode if write this:
frmView1.DefaultMode = FormViewMode.ReadOnly
forview shows the content of InsertItemTemplate. Could someone please explain what's going on here?

Answer 1

FormView won't show unless you bind, something like this:
using(SqlDataAdapter adapter = new SqlDataAdapter(sql,connection))
{
DataTable table = new DataTable();
adapter.Fill(table);
FormView1.DataSource = table;
FormView1.DataBind();
}
And just add EmptyDataTemplate tag to show empty message if your datasource don't return any value.
<EmptyDataTemplate>
There is nothing to see here.
</EmptyDataTemplate>
follow this tutorial and more about this on MSDN

Answer 2

In your code
<asp:Button ID="btnSubmit" Text="Submit" runat="server" />
must change to
<asp:Button ID="btnSubmit" Text="Submit" runat="server" command="ChangeModeToReadOnly" OnCommand="Button_Command" />
Instead of implementing OnClick event implement this
Protected Sub Button_Command(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.CommandEventArgs)
Select Case e.CommandName
Case "ChangeModeToReadOnly"
frmView1.ChangeMode(FormViewMode.ReadOnly)
End Select
End Sub

Answer 3

You can try with adding the following DataBound function
protected void myFormView_DataBound(object sender, EventArgs e)
{
frmView1.ChangeMode(FormViewMode.ReadOnly);
}
The syntax is in C#