Cast Error in Linq Query - vb.net

Question

I'm trying to get data for a gridview and have a cast error.
In the code below, if I just return "myuserlist" - all is good. As soon as I try to select only 2 fields (as in this code), I get the casting error. I've looked at other comments posted here regarding this problem and tried a number of things with no success.
Imports System.Linq
Imports RoutesEntities
Partial Class ProfileTest
Inherits System.Web.UI.Page
Private myentity As New RoutesEntities()
Public Function GridView1_GetData() As IQueryable(Of AllUser)
Return From myuserlist In myentity.AllUsers Select New With {myuserlist.UserName,myuserlist.Email}
End Function
Error:
System.InvalidCastException was unhandled by user code
HResult=-2147467262
Message=Unable to cast object of type 'System.Data.Entity.Infrastructure.DbQuery`1[VB$AnonymousType_0`2[System.String,System.String]]' to type 'System.Linq.IQueryable`1[AllUser]'.
Source=App_Web_oelfrca5
StackTrace:
at ProfileTest.GridView1_GetData() in C:\xxx\yyy\zzz\Profile.aspx.vb:line 10
InnerException:
I tried this (among other things):
Return From myuserlist In myentity.AllUsers Select New AllUser() With {
.UserName = myuserlist.UserName,
.Email = myuserlist.Email}
and got this:
Exception Details: System.NotSupportedException: The entity or complex type 'RoutesModel.AllUser' cannot be constructed in a LINQ to Entities query.

Answer 1

If you don't need the specific AllUser type at compile-time, you can have your function return an IQueryable(Of Object), or perhaps even a simple IQueryable:
Public Function GridView1_GetData() As IQueryable
Return From myuserlist In myentity.AllUsers Select New With {myuserlist.UserName,myuserlist.Email}
End Function
Update Return IQueryable(Of Object) if you'll need LINQ on the results:
Sub DataTest()
Dim qry = GridView1_GetData
Dim filteredQry = qry.Take(5)
End Sub
It is easier to do this with VB.NET than in C#, because VB.NET supports late binding -- even though the variable `x` is of type `Object`, and thus may not have a `UserName` property, the compiler will allow `UserName` to be resolved at runtime.
This is not as useful as it might be, because you can't pass an expression into the LINQ operator, e.g. you can use .Take or one overload of .Any, but not .Where.