Question

I tried to translate following C# code

public static class ObjectSetExtensions
{
    public static void AddObjects<T>(this ObjectSet<T> objectSet, IEnumerable<T> objects)
    {
         foreach (var item in objects)
         {
             objectSet.AddObject(item);
         }
    }
}

to VB.NET:

Module ObjectSetExtensions
    <System.Runtime.CompilerServices.Extension()>
    Public Sub AddObjects(Of T)(ByVal objectSet As ObjectSet(Of T), ByVal objects As IEnumerable(Of T))
        For Each item In objects
            objectSet.AddObject(item)
        Next
    End Sub
End Module

But I getting an error that says:

Type argument ‘T’ does not satisfy the ‘Class’ constraint for type parameter ‘TEntity’.

What am I missing?

Answer 1

The C# version doesn’t compile either, for the same reason. It should be:

public static void AddObjects<T>(this ObjectSet<T> objectSet,
                                 IEnumerable<T> objects)
    where T : class // Note this bit
{
     foreach (var item in objects)
     {
         objectSet.AddObject(item);
     }
}

And the VB version is:

<Extension> _
Public Sub AddObjects(Of T As Class)(ByVal objectSet As ObjectSet(Of T), _
                                     ByVal objects As IEnumerable(Of T))
    Dim local As T
    For Each local In objects
        objectSet.AddObject(local)
    Next
End Sub

Note how in the VB version the constraint is part of the type parameter declaration. For more details, see MSDN.