[InvalidOperationException: Sequence contains more than one element]
System.Linq.Enumerable.SingleOrDefault(IEnumerable`1 source) +470
Book.Page_Load(Object sender, EventArgs e) in d:\hostingspaces\cargo1.ir\raspid.ir\Book.aspx.cs:32
System.Web.UI.Control.OnLoad(EventArgs e) +108
System.Web.UI.Control.LoadRecursive() +90
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1533
|