DragPanel控件的目的是实现一个可以自由拖动的Panel.
属性列表：
TargetControlID – 指定可以拖动的面板的ID
DragHandleID – 指定一个ID，作为拖动面板的标题栏。
实例解析一、创建可拖动的面板实例
<form id="form1" runat="server">
<div>
<asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
</div>
<asp:Panel ID="Panel1" runat="server" Height="257px" Width="375px">
<asp:Panel ID="Panel2" runat="server" Height="38px" Width="397px" BackColor="red">拖动此处
</asp:Panel>
<asp:Panel ID="Panel3" runat="server" Height="266px" Width="396px">
<asp:Button ID="Button1" runat="server" Text="Button" /></asp:Panel>
</asp:Panel>
<cc1:DragPanelExtender ID="DragPanelExtender1" runat="server" TargetControlID="Panel1" DragHandleID="Panel2">
</cc1:DragPanelExtender>
</form>