Ajax Rounded Corners control is a very good control to make rounded type shape.
Here by using Corners property of Ajax Rounded Corner property we can design shape in many form.

Here is the ASPX code.

<%@ Page Language="C#" AutoEventWireup="true"
CodeFile="Default.aspx.cs" Inherits="_Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"

"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">



<html xmlns="http://www.w3.org/1999/xhtml">

<head runat="server">

<title>AJAX: RoundedCorners</title>

</head>

<body>

<form id="form1" runat="server">

<asp:ScriptManager ID="ScriptManager1" runat="server">

</asp:ScriptManager>

<div>

<table cellpadding="0" cellspacing="0" width="50%" align="center">

<tr>

<td>

<asp:Panel ID="PanelLogin" runat="server" Height="190px" Width="395px" BackColor="#00AEEF">

<div>

<table cellspacing="3" width="98%" align="center" style="margin: 0px 5px 0px 5px;">

<tr>

<td align="center" style="font-weight: bold;">

AJAX: A Good Control To Make rounded Corner

</td>

</tr>

</table>

</div>

</asp:Panel>

</td>

</tr>

</table>

</div>

<div>

<ajaxToolkit:RoundedCornersExtender ID="rce" runat="server" TargetControlID="PanelLogin"

Corners="Top" Radius="6" />

</div>

</form>

</body>

</html>

When I run the Application and I set Corners="None" Then
Corner None.JPG

When I run the Application and I set Corners="Bottom" Then

Corner None.JPG

When I run the Application and I set Corners="BottomLeft" Then

Corner None.JPG

When I run the Application and I set Corners="Right" Then

Corner None.JPG

When I run the Application and I set Corners="Top" Then