How to use button click event in asp.net c#

Button OnClick() method and click event
Button is an asp.net web server control. this control displays a push button control on the web page. button server control is exists under System.Web.UI.WebControls namespace. button control allow the users to post a page to the web server. by default, a button control is a submit button.

Button OnClick() method raises the click event of the button control.

Button Click event occurs when the button control is clicked. the click event is commonly used when button control have no associate command name such as a submit button. we can specify a button's command name by its CommandName property. submit button does not have a command name and its simply posts the page back to the web server. we can write an event handler for click event to programmatically perform any action when submit button is clicked.

the following asp.net c# example code demonstrate us how can we use click event in button control.

in this example code we created two buttons and a label control. both buttons have a click event and we provided the click event handler for both of them. when someone click any one button then the specified button’s click event raise and after post back the label control display which button is clicked.
ButtonOnClickExample.aspx

<%@ Page Language="C#" %>

<!DOCTYPE html>

<script runat="server">
    protected void Button1_Click(object sender, System.EventArgs e)
    {
        Label1.Text = "You clicked the first button.";
    }

    protected void Button2_Click(object sender, System.EventArgs e)
    {
        Label1.Text = "You clicked the second button.";
    }
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>How to use Button Click event in asp.ent</title>
</head>
<body style="padding:25px">
    <form id="form1" runat="server">
    <div>
        <h2 style="color:MidnightBlue; font-style:italic;">      
            Button OnClick() method and click event
        </h2>      
        <hr width="450" align="left" color="Gainsboro" />
        <asp:Label 
            ID="Label1" 
            runat="server" 
            Font-Size="X-Large" 
            ForeColor="Crimson"
            Font-Italic="true"
            />
        <br /><br />
        <asp:Button 
            ID="Button1" 
            runat="server" 
            Text="First Button" 
            OnClick="Button1_Click"
            Font-Bold="true"
            ForeColor="DodgerBlue"
            Height="45"
            Width="150"
            />
        <asp:Button 
            ID="Button2" 
            runat="server" 
            Text="Second Button" 
            OnClick="Button2_Click"
            Font-Bold="true"
            ForeColor="DodgerBlue"
            Height="45"
            Width="150"
            />
    </div>
    </form>
</body>
</html>