<ajaxToolkit:DropShadowExtender ID="dse" runat="server"
TargetControlID="Panel1"
Opacity=".8"
Rounded="true"
TrackPosition="true" />
· TargetControlID - The ID of the button or link for this extender to operate on
· Width – 阴影的宽度,默认是5.
· Opacity -阴影的透明度(0(不透明)-1.0(全不透明))默认是5.
· TrackPosition – 阴影是否跟随控件一起动.
· Rounded – 阴影是否有圆角. 默认是 false
效果:http://www.asp.net/AJAX/Control-Toolkit/Live/DropShadow/DropShadow.aspx