泛型接口 (C++/CLI)
类和接口中的类型参数要遵循的限制相同（请参阅泛型类 (C++/CLI)）。
对于泛型类或泛型接口中的函数，控制函数重载的规则是相同的。
显式接口成员实现处理构造接口类型和简单接口类型的方式相同（请参阅下面的示例）。
若要详细了解接口，请参阅 interface class。
语法
[attributes] generic <class-key type-parameter-identifier[, ...]>
[type-parameter-constraints-clauses][accesibility-modifiers] interface class identifier [: base-list] { interface-body} [declarators] ;
备注
attributes
（可选）其他声明性信息。 若要详细了解特性和特性类，请参阅“attribute”。
class-key
class 或 typename
type-parameter-identifier(s)
标识符的逗号分隔列表。
type-parameter-constraints-clauses
采用泛型类型参数的约束 (C++/CLI) 中指定的形式
accessibility-modifiers
（可选）可访问性修饰符（例如，public、private）。
identifier
接口名称。
base-list
（可选）包含一个或多个显式基接口的逗号分隔列表。
interface-body
接口成员的声明。
declarators
（可选）基于此类型的变量的声明。
示例：如何声明和实例化泛型接口
下面的示例展示了如何声明和实例化泛型接口。 此示例声明泛型接口 IList<ItemType>。 然后，两个泛型类（List1<ItemType> 和 List2<ItemType>）通过不同实现来实现它。
// generic_interface.cpp
// compile with: /clr
using namespace System;
// An exception to be thrown by the List when
// attempting to access elements beyond the
// end of the list.
ref class ElementNotFoundException : Exception {};
// A generic List interface
generic <typename ItemType>
public interface class IList {
ItemType MoveFirst();
bool Add(ItemType item);
bool AtEnd();
ItemType Current();
void MoveNext();
};
// A linked list implementation of IList
generic <typename ItemType>
public ref class List1 : public IList<ItemType> {
ref class Node {
ItemType m_item;
public:
ItemType get_Item() { return m_item; };
void set_Item(ItemType value) { m_item = value; };
Node^ next;
Node(ItemType item) {
m_item = item;
next = nullptr;
}
};
Node^ first;
Node^ last;
Node^ current;
public:
List1() {
first = nullptr;
last = first;
current = first;
}
virtual ItemType MoveFirst() {
current = first;
if (first != nullptr)
return first->get_Item();
else
return ItemType();
}
virtual bool Add(ItemType item) {
if (last != nullptr) {
last->next = gcnew Node(item);
last = last->next;
}
else {
first = gcnew Node(item);
last = first;
current = first;
}
return true;
}
virtual bool AtEnd() {
if (current == nullptr )
return true;
else
return false;
}
virtual ItemType Current() {
if (current != nullptr)
return current->get_Item();
else
throw gcnew ElementNotFoundException();
}
virtual void MoveNext() {
if (current != nullptr)
current = current->next;
else
throw gcnew ElementNotFoundException();
}
};
// An array implementation of IList
generic <typename ItemType>
ref class List2 : public IList<ItemType> {
array<ItemType>^ item_array;
int count;
int current;
public:
List2() {
// not yet possible to declare an
// array of a generic type parameter
item_array = gcnew array<ItemType>(256);
count = current = 0;
}
virtual ItemType MoveFirst() {
current = 0;
return item_array[0];
}
virtual bool Add(ItemType item) {
if (count < 256)
item_array[count++] = item;
else
return false;
return true;
}
virtual bool AtEnd() {
if (current >= count)
return true;
else
return false;
}
virtual ItemType Current() {
if (current < count)
return item_array[current];
else
throw gcnew ElementNotFoundException();
}
virtual void MoveNext() {
if (current < count)
++current;
else
throw gcnew ElementNotFoundException();
}
};
// Add elements to the list and display them.
generic <typename ItemType>
void AddStringsAndDisplay(IList<ItemType>^ list, ItemType item1, ItemType item2) {
list->Add(item1);
list->Add(item2);
for (list->MoveFirst(); ! list->AtEnd(); list->MoveNext())
Console::WriteLine(list->Current());
}
int main() {
// Instantiate both types of list.
List1<String^>^ list1 = gcnew List1<String^>();
List2<String^>^ list2 = gcnew List2<String^>();
// Use the linked list implementation of IList.
AddStringsAndDisplay<String^>(list1, "Linked List", "List1");
// Use the array implementation of the IList.
AddStringsAndDisplay<String^>(list2, "Array List", "List2");
}
Linked List
List1
Array List
List2
示例：声明泛型接口
下面的示例声明一个泛型接口 IMyGenIface，以及两个专用化 IMyGenIface 的非泛型接口（IMySpecializedInt 和 ImySpecializedString）。 然后，两个专用化接口由两个类（MyIntClass 和 MyStringClass）实现。 此示例展示了如何专用化泛型接口、如何实例化泛型接口和非泛型接口，以及如何调用接口中已显式实现的成员。
// generic_interface2.cpp
// compile with: /clr
// Specializing and implementing generic interfaces.
using namespace System;
generic <class ItemType>
public interface class IMyGenIface {
void Initialize(ItemType f);
};
public interface class IMySpecializedInt: public IMyGenIface<int> {
void Display();
};
public interface class IMySpecializedString: public IMyGenIface<String^> {
void Display();
};
public ref class MyIntClass: public IMySpecializedInt {
int myField;
public:
virtual void Initialize(int f) {
myField = f;
}
virtual void Display() {
Console::WriteLine("The integer field contains: {0}", myField);
}
};
public ref struct MyStringClass: IMySpecializedString {
String^ myField;
public:
virtual void Initialize(String^ f) {
myField = f;
}
virtual void Display() {
Console::WriteLine("The String field contains: {0}", myField);
}
};
int main() {
// Instantiate the generic interface.
IMyGenIface<int>^ myIntObj = gcnew MyIntClass();
// Instantiate the specialized interface "IMySpecializedInt."
IMySpecializedInt^ mySpIntObj = (IMySpecializedInt^) myIntObj;
// Instantiate the generic interface.
IMyGenIface<String^>^ myStringObj = gcnew MyStringClass();
// Instantiate the specialized interface "IMySpecializedString."
IMySpecializedString^ mySpStringObj =
(IMySpecializedString^) myStringObj;
// Call the explicitly implemented interface members.
myIntObj->Initialize(1234);
mySpIntObj->Display();
myStringObj->Initialize("My string");
mySpStringObj->Display();
}
The integer field contains: 1234
The String field contains: My string