How to: Iterate Over a Generic Collection with for each

孙明明 — Mon, 16 Jul 2007 15:42:00 GMT

1// for_each_generics.cpp
2// compile with: /clr
3using namespace System;
4using namespace System::Collections::Generic;
5
6generic <class T>
7public value struct MyArray : public IEnumerable<T> {
8
9   MyArray( array<T>^ d ) {
10      data = d;
11   }
12
13   ref struct enumerator : IEnumerator<T> {
14      enumerator( MyArray^ myArr ) {
15         colInst = myArr;
16         currentIndex = -1;
17      }
18
19      virtual bool MoveNext() = IEnumerator<T>::MoveNext {
20         if ( currentIndex < colInst->data->Length - 1 ) {
21            currentIndex++;
22            return true;
23         }
24
25         return false;
26      }
27
28      virtual property T Current {
29         T get() {
30            return colInst->data[currentIndex];
31         }
32      };
33
34      property Object^ CurrentNonGeneric {
35         virtual Object^ get() = System::Collections::IEnumerator::Current::get {
36            return colInst->data[currentIndex];
37         }
38      };
39
40      virtual void Reset() {}
41      ~enumerator() {}
42
43      MyArray^ colInst;
44      int currentIndex;
45   };
46
47   array<T>^ data;
48
49   virtual IEnumerator<T>^ GetEnumerator() {
50      return gcnew enumerator(*this);
51   }
52   virtual System::Collections::IEnumerator^ GetEnumeratorNonGeneric() = System::Collections::IEnumerable::GetEnumerator {
53      return gcnew enumerator(*this);
54   }
55};
56
57int main() {
58   MyArray<int> col = MyArray<int>( gcnew array<int>{10, 20, 30 } );
59
60   for each ( Object^ c in col )
61      Console::WriteLine((int)c);
62}
63

孙明明 2007-07-16 23:42 发表评论

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How to: Iterate Over a Generic Collection with for each