Simple LINQ question - how to iterate through a group?

Question

I need some help with a LINQ query in VB.Net, please.

I have this simple group statement:

Dim drivers = From d In DriversOwners _
   Group d By Key = d.UnitNumber Into Group _
   Select Key, DriverGroup = Group

This works, and returns me the data I need to work with. Now I want to iterate through the groups, using a For Each construct. like this:

For Each x In drivers

Next

However, the compiler is barking at me, telling me that the

"'x' is not accessible in this context because it is 'Friend'."

Anyone know what I am doing wrong here?

Thanks in advance.

Answer 1

Looks to me like the variable x was declared earlier - as a class field, a method parameter, or a local variable.

Am I right?

Answer 2

After digging and digging, I finally found the answer to this problem. Talk about obtuse!

Enabling LINQ in a .NET Framework 3.5 Project

When you move a project to .NET Framework 3.5, a reference to System.Core and a project-level import for System.Linq (in Visual Basic only) are added automatically. If you want to use LINQ features, you must also turn Option Infer on (in Visual Basic only) [my emphasis].

When I changed the target framework from 2.0 to 3.5, Visual Studio automatically added the System.Core assembly, and automatically imported the System.Linq namespace. Now why in the world did it not also set Option Infer to "On" as well?

http://msdn.microsoft.com/en-us/library/bb398197.aspx

Answer 3

I'm not sure if you've solved this or not. I had the exact same problem today and what ended up working for me was to not use a single-letter variable in the For Each loop. My code was the same as yours:

For Each x In a
 ...
Next

When I changed the code to the following it worked:

For Each retVal in a
 ...
Next

I also found the same 'Friend' error behavior for any single-letter variable.

I have no idea why it behaves this way, but I thought I'd pass this along in case this question is still out there.