How do I extract a value from a Linq IQueryable object? - vb.net

Question

I am new to Linq and have been stumped for several days. I have searched this and several other boards to find the answer but cannot. I have a Linq query that is returning 1 value of int.
Public Function myV()
Dim MR As New MainEntities()
Dim mV = From AspNetUsers In MR.AspNetUsers
Where Context.User.Identity.Name() = AspNetUsers.Email.ToString Select AspNetUsers.VB
Return mV
End Function
If myV = 1 Then
perform other code
End If
But when I try to compare to an Int it says the object cannot be compared. I have tried to convert the IQueryable(of Interger) to Int and cannot. How do I get to the Interger value in the IQueryable object?

Answer 1

The LINQ statement returns an IEnumerable, which is like an array in that it can hold multiple values, even it only happens to have one value in it.
The best way to return a single value is .First(), or .Single() if you want to throw an exception if more than one value exists. (Which one you choose depends on your context.)
Public Function myV()
Dim MR As New MainEntities()
Dim mV = From AspNetUsers In MR.AspNetUsers
Where Context.User.Identity.Name() = AspNetUsers.Email.ToString Select AspNetUsers.VB.First()
Return mV
End Function

Answer 2

Because mV is an IQueryable, you can consider it as a type of list or an array. So you need to get the first value:
If myV.First() = 1 Then
'...
End If
Or more likely you want to do that inside the mV function:
Dim mV = From AspNetUsers In MR.AspNetUsers
Where Context.User.Identity.Name() = AspNetUsers.Email.ToString
Select AspNetUsers.VB
Return mV.First()

Answer 3

You misunderstood the query. Your LINQ executes a SQL Statement that is the follows:
SELECT AspNetUsers.VB
FROM AspNetUsers
WHERE ApsNetUsers.Email = "here the name"
Therefore the query does not return only one VB but a table consisting of one column and multiple rows.
In order to retrieve the first value you have to call .First()
If myV.First() = 1 Then [...]