EnumerableComCollection<TComEnumerator,TEnumerated> Class

Definition

generic <typename TComEnumerator, typename TEnumerated>
public ref class EnumerableComCollection abstract : Microsoft::VisualStudio::Shell::IComEnumeratorRelay<TComEnumerator, TEnumerated>, System::Collections::Generic::IEnumerable<TEnumerated>

public abstract class EnumerableComCollection<TComEnumerator,TEnumerated> : Microsoft.VisualStudio.Shell.IComEnumeratorRelay<TComEnumerator,TEnumerated>, System.Collections.Generic.IEnumerable<TEnumerated>

type EnumerableComCollection<'ComEnumerator, 'Enumerated> = class
    interface seq<'Enumerated>
    interface IEnumerable
    interface IComEnumeratorRelay<'ComEnumerator, 'Enumerated>

Public MustInherit Class EnumerableComCollection(Of TComEnumerator, TEnumerated)
Implements IComEnumeratorRelay(Of TComEnumerator, TEnumerated), IEnumerable(Of TEnumerated)

Type Parameters

Inheritance

Object

EnumerableComCollection<TComEnumerator,TEnumerated>

Derived

Microsoft.VisualStudio.Shell.EnumerableHierarchiesCollection

Implements

IComEnumeratorRelay<TComEnumerator,TEnumerated> IEnumerable<TEnumerated> IEnumerable

Remarks

Classes that derive from this class adapt a COM-style IEnumXXX interface into an form that can be processed by a foreach statement. Ideally this generic class would be sufficient on its own without the need for a derived class to do the job, but the rigor with which C# generics must be defined prevents that.

This class must call methods on the COM enumerator that it wraps (Next, Skip, etc.), but generic types can only access properties and methods on their parameterized types that are specified in the parameterized types' constraints. Specifically, we can only call TComEnumerator.Next if we specify a constraint on TComEnumerator that tells the compiler that TComEnumerator implements Next.

COM IEnumXXX interfaces are strongly typed (i.e. IEnumXXX.Next returns an array of XXX objects) and do not have a common base class, so we can't place a constraint on TComEnumerator directly. This is where IComEnumeratorRelay comes in: EnumerableComCollection requires that its derived class implements the strongly-typed IComEnumeratorRelay interface which allows the generic type to call into the COM enumerator without having to place a constraint on TComEnumerator.

Constructors

Fields

Methods

Explicit Interface Implementations

Extension Methods

Applies to