Why the following code produces the error?
The query operator 'ElementAtOrDefault' is 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 of fixing 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)
What you need to do is add .ToList()
to the end of your query. 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()
, the query just returns a DataQuery(Of T) instead of a List(Of T). Adding the ToList call does two things:
Hope that helps!
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