Need help with query strings

Hey guys,
I've looked over the web and didn't find much help. Can someone help me concatenate some strings. I have this URL and it works fine but i want to add itemStatus="c" to my query string. Here's what i have so far:
 
NavigateUrl='<%# "javascript:void(window.open(\"itemProduct.aspx?itemNumber=" + DataBinder.Eval(Container.DataItem,"item_no").ToString() + "\", null, \"width=400,height=400,resizable=1,scrollbars=1\"))" %>'
 
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