How can I add the http prefix into my gridview eval value
<asp:HyperLink Target="_blank"
NavigateUrl='<%# Eval("SourceURL").ToString().Contains("http:")==true?
Eval("SourceURL") :
'http://'+ Eval("SourceURL") %>'
runat="server" ID="Sorceurl"
Visible='<%# Eval("SourceURL") == String.Empty ? false : true %>'
Text="Source"></asp:HyperLink>