How to send value via URL from aspx page to ascx page in asp.net

 Hi,
I need help, I want to send value via URL from aspx page to ascx page. I did it, but the variables in my ascx.cs page were empty. I don't know why. I used those code:
 <web_parts:topic ID="parts" runat="server"  Id='<%# Request.QueryString.Get("id") %>' TId='<%# Request.QueryString.Get("t_id") %>'/>

 Maybe I did mistake, please help me.

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