How to use Command Event

Default.aspx

 <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
        <asp:Button ID="Button1" runat="server" Text="Button" CommandName="button1" CommandArgument="button1" OnCommand="CommandBtn_Click" />
        <asp:ImageButton ID="ImageButton1" runat="server" CommandName="ImageButton1" CommandArgument="ImageButton1"
        OnCommand="CommandBtn_Click" />

code behind

  protected void CommandBtn_Click(object sender, CommandEventArgs e)
    {
        switch (e.CommandName)
        {
            case "ImageButton1":
                
                Label1.Text = "imagebuttonclicked";
                
            break;

            case "button1":
            
                Label1.Text = "Button1 clicked";
            break;

        }
    }