Switch from ASPX "Source" to C# codebehind

First, Make sure you have included “CodeBehind” property value in the page directive like below highlighted –

Second, attach “OnClick” event of the button in source file like below –

<asp:Button ID="button1" runat="server" Text="Insert" Font-Bold="true" OnClick="button1_Click"/>

Third, Add event handler method into your code-behind file like below –

protected void button1_Click(object sender, EventArgs e)

{

}