public partial class select : System.Web.UI.Page
{

protected void Page_Load(object sender, EventArgs e)
{
char Destination;

if(Page.IsPostBack)
{
switch(Destination.Selecteditem.value)
{
case "北京":
Response.Write("你选择了北京");
break;
case "上海":
Response.Write("你选择了上海");
break;
case "深圳":
Response.Write("你选择了深圳");
break;
default:
Response.Write("你没有任何选择");
break;
}
}

}
}

我不太懂，麻烦你告诉我应该怎么改？