如何使用与UpdatePanel类似的标记使用内部属性创建ASP.NET用户控件？

I am creating a user control that I wish to have inner properties as well as normal attributes. Although the actual function of the control has nothing to do with, say, UpdatePanel, I am trying to create something with similar ASPX markup. The developer designing the page should be able to use my control like:I am creating a user control that I wish to hav