Refresh GridView1 in UpdatePanel1 after first executing the code in Button1_Click - asp.net

Question

I would like to update UpdatePanel1 after executing the code in Button1_Click.
UpdatePanel1.Update() is not updating GridView1.
The trigger in UpdatePanel1, I think, is firing immediately after Button1 is pushed instead of after executing the code in the pushbutton event.
I would like to refresh GridView1 in UpdatePanel1 after first executing the code in Button1_Click.
Default.aspx.vb
Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button3.Click
Dim connStr As String = "connection string works"
Dim cmdStr As String = "INSERT INTO [test] ([datetime],[col1],[col2],[col3]) VALUES (#datetime,#col1,#col2,#col3);"
Try
Using conn As New SqlConnection(connStr)
Using cmd As New SqlCommand(cmdStr, conn)
conn.Open()
cmd.Parameters.AddWithValue("#datetime", DateTime.Now)
cmd.Parameters.AddWithValue("#col1", TextBox1.Text)
cmd.Parameters.AddWithValue("#col2", TextBox2.Text)
cmd.Parameters.AddWithValue("#col3", TextBox3.Text)
cmd.ExecuteNonQuery()
conn.Close()
cmd.Dispose()
conn.Dispose()
End Using
End Using
Catch ex As Exception
End Try
UpdatePanel1.Update()
End Sub
Default.aspx
<asp:UpdatePanel ID="UpdatePanel1" UpdateMode="Conditional" runat="server">
<Triggers>
<asp:AsyncPostBackTrigger ControlID="Button1" EventName="Click"></asp:AsyncPostBackTrigger>
</Triggers>
<ContentTemplate>
<center><table><tr><td align="center">
<asp:Label ID="Label4" runat="server" Text="Column 1"></asp:Label></td><td align="center">
<asp:Label ID="Label5" runat="server" Text="Column 2"></asp:Label></td><td align="center">
<asp:Label ID="Label6" runat="server" Text="Column 3"></asp:Label><br /></td></tr><tr><td align="center">
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox></td><td align="center">
<asp:TextBox ID="TextBox2" runat="server"></asp:TextBox></td><td align="center">
<asp:TextBox ID="TextBox3" runat="server"></asp:TextBox><br /></td></tr><tr><td colspan="3" align="center">
<asp:Button ID="Button1" runat="server" Text="Insert Into Gridview" /></td></tr><tr><td><br />
<asp:GridView ID="GridView1"
DataSourceID="SqlDataSource1"
AutoGenerateColumns="true"
AllowPaging="true"
PageSize="50"
AllowSorting="true"
DataKeyNames="idt"
AutoGenerateEditButton="true"
AutoGenerateDeleteButton="true"
runat="server">
</asp:GridView>
<asp:SqlDataSource
ID="SqlDataSource1"
ConnectionString="<%$ ConnectionStrings:connone %>"
SelectCommand="SELECT * FROM [test];"
DataSourceMode="DataSet"
UpdateCommand="UPDATE test [datetime],[col1],[col2],[col3] SET #datetime, #col1, #col2, #col3;"
DeleteCommand="DELETE FROM [test] WHERE [idt]=#idt;"
runat="server">
</asp:SqlDataSource>
</td></tr></table></center>
</ContentTemplate>
</asp:UpdatePanel>

Answer 1

You don't need to call UpdatePanel1.Update() in your Button1_Click method since Button1 is a trigger for your UpdatePanel. Instead you must call GridView1.DataBind() to refetch data from DB, like this :
Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button3.Click
Dim connStr As String = "connection string works"
Dim cmdStr As String = "INSERT INTO [test] ([datetime],[col1],[col2],[col3]) VALUES (#datetime,#col1,#col2,#col3);"
Try
Using conn As New SqlConnection(connStr)
Using cmd As New SqlCommand(cmdStr, conn)
conn.Open()
cmd.Parameters.AddWithValue("#datetime", DateTime.Now)
cmd.Parameters.AddWithValue("#col1", TextBox1.Text)
cmd.Parameters.AddWithValue("#col2", TextBox2.Text)
cmd.Parameters.AddWithValue("#col3", TextBox3.Text)
cmd.ExecuteNonQuery()
conn.Close()
cmd.Dispose()
conn.Dispose()
End Using
End Using
Catch ex As Exception
End Try
GridView1.Databind()
End Sub