Lets take an simple Example
<%@ Page
Language="C#"
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD
XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
protected void
Button1_Click(object sender, EventArgs e)
{
CheckBoxList1.BorderStyle = BorderStyle.Dashed;
}
protected void
Button2_Click(object sender, EventArgs e)
{
CheckBoxList1.BorderStyle = BorderStyle.Dotted;
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>CHANGE BORDER STYLE PROGRAMMATICALLY</title>
</head>
<body>
<form id="form1" runat="server">
<asp:CheckBoxList ID="CheckBoxList1"
runat="server"
Height="24px"
Width="208px">
<asp:ListItem>ASP.NET
CONTROLS</asp:ListItem>
<asp:ListItem>JAVA CONTROLS</asp:ListItem>
<asp:ListItem>TURBO CONTROLS</asp:ListItem>
<asp:ListItem>PYTHON CONTROL</asp:ListItem>
</asp:CheckBoxList>
<div>
<br />
<asp:Button ID="Button1"
runat="server"
onclick="Button1_Click"
Text="DASHED BORDER
STYLE" Width="178px"
/>
<br />
<br />
<asp:Button ID="Button2"
runat="server"
onclick="Button2_Click"
Text="DOTTED BORDER
STYLE" Width="178px"
/>
</div>
</form>
</body>
</html>