LINQ: query statement "ElementAtOrDefault" is not supported

Question

Why is the following code causing an error?

ElementAtOrDefault query statement not supported

Dim Im = (From view In Db.Views Where _ view.Pass = txtCode.Text _ Select New With {.Id = view.UniqueID.ToString}_ ).Distinct Response.Redirect("~/test.aspx?x=" & Im(0).Id) 

Is there any way to fix it without using the FirstOrDefault option?

UPDATE: And here is the StackTrace

  at System.Data.Linq.SqlClient.QueryConverter.VisitSequenceOperatorCall(MethodCallExpression mc) at System.Data.Linq.SqlClient.QueryConverter.VisitMethodCall(MethodCallExpression mc) at System.Data.Linq.SqlClient.QueryConverter.VisitInner(Expression node) at System.Data.Linq.SqlClient.QueryConverter.ConvertOuter(Expression node) at System.Data.Linq.SqlClient.SqlProvider.BuildQuery(Expression query, SqlNodeAnnotations annotations) at System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query) at System.Data.Linq.DataQuery`1.System.Linq.IQueryProvider.Execute[S](Expression expression) at System.Linq.Queryable.ElementAtOrDefault[TSource](IQueryable`1 source, Int32 index) at Login.btnLogin_Click(Object sender, EventArgs e) in D:\Projects\Memoria\Login.aspx.vb:line 14 at System.Web.UI.WebControls.Button.OnClick(EventArgs e) at System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) at System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) at System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) 

Answer 1

What you need to do is add .ToList() to the end of your request. This should work:

 Dim Im = (From view In Db.Views Where _ view.Pass = txtCode.Text _ Select New With {.Id = view.UniqueID.ToString}_ ).Distinct.ToList() Response.Redirect("~/test.aspx?x=" & Im(0).Id) 

Without .ToList() query simply returns DataQuery (Of T) instead of List (Of T). Adding a ToList call does two things:

• Causes the request to execute immediately, and
• Returns a collection type that supports ElementAtOrDefault ()

Hope this helps!