我使用 Delphi 2006,我有一个名为的复杂类TMyClassTest
,它有许多方法其中一些方法创建非可视组件并分配这些组件的事件处理程序并运行这些组件的方法。
我也有两个实现相同接口的类,如下所示:
TMyClass1 = class(Class1, Interface1)
... //procedures from the Interface1
procedure MyClass1Proc1;
end;
TMyClass2 = class(Class2, Interface1)
... //procedures from the Interface1
procedure MyClass2Proc1;
procedure MyClass2Proc2
end;
现在我也需要 TMyClass1 和 TMyClass2 来“继承” TMyClassTest。更多... Interface1 必须包含(除了它的方法之外)来自 MyClassTest 的所有方法。如何避免在两个类(TMyClass1 和 TMyClass2)上实现(如复制/粘贴) TMyClassTest 中的所有程序?我不想在三个不同的地方保留相同的代码。
根据 Arioch 的评论,我创建了一个解决方案,例如:(参见http://docwiki.embarcadero.com/RADStudio/XE3/en/Implementing_Interfaces#Implementing_Interfaces_by_Delegation_.28Win32_only.29)
type
IMyInterface = interface
procedure P1;
procedure P2;
end;
TMyImplClass = class
procedure P1;
procedure P2;
end;
TMyClass1 = class(Class1, IMyInterface)
FMyImplClass: TMyImplClass;
property MyImplClass: TMyImplClass read FMyImplClass implements IMyInterface;
procedure IMyInterface.P1 = MyP1;
procedure MyP1;
end;
TMyClass2 = class(TInterfacedObject, IMyInterface)
FMyImplClass: TMyImplClass;
property MyImplClass: TMyImplClass read FMyImplClass implements IMyInterface;
procedure P3;
procedure P4;
end;
procedure TMyImplClass.P1;
// ...
procedure TMyImplClass.P2;
// ...
procedure TMyClass1.MyP1;
// ...
procedure TMyClass2.P3;
// ...
procedure TMyClass2.P4;
// ...
var
MyClass: TMyClass1;
MyInterface: IMyInterface;
begin
MyClass := TMyClass1.Create;
MyClass.FMyImplClass := TMyImplClass.Create; //Error !!!! FMyImplClass is a read only property !!!
MyInterface := MyClass;
MyInterface.P1; // calls TMyClass1.MyP1;
MyInterface.P2; // calls TImplClass.P2;
end;
MyClass.FMyImplClass := TMyImplClass.Create;
因为我在尝试创建FMyImplClass
声明构造函数时遇到错误,TMyClass1
但TMyClass2
不能正常工作。还有其他方法可以创建FMyImplClass
吗?
现在我尝试了一个似乎可以正常工作的解决方案。会不会有一些隐藏的影响?
type
IMyInterface = interface
procedure P1;
procedure P2;
procedure CreateFMyImplClass;
end;
TMyImplClass = class
procedure P1;
procedure P2;
end;
TMyClass1 = class(Class1, IMyInterface)
FMyImplClass: TMyImplClass;
property MyImplClass: TMyImplClass read FMyImplClass implements IMyInterface;
procedure IMyInterface.P1 = MyP1;
procedure MyP1;
procedure CreateFMyImplClass;
end;
TMyClass2 = class(TInterfacedObject, IMyInterface)
FMyImplClass: TMyImplClass;
property MyImplClass: TMyImplClass read FMyImplClass implements IMyInterface;
procedure P3;
procedure P4;
procedure CreateFMyImplClass;
end;
procedure TMyImplClass.P1;
// ...
procedure TMyImplClass.P2;
// ...
procedure TMyClass1.MyP1;
// ...
procedure TMyClass1.CreateFMyImplClass;
begin
FMyImplClass := TMyImplClass.Create;
end;
procedure TMyClass2.P3;
// ...
procedure TMyClass2.P4;
// ...
procedure TMyClass2.CreateFMyImplClass;
begin
FMyImplClass := TMyImplClass.Create;
end;
var
MyInterface: IMyInterface;
begin
if WantRemote then
MyInterface := TMyClass1.Create
else
MyInterface := TMyClass2.Create;
MyInterface.CreateFMyImplClass; // create FMyImplClass ;
MyInterface.P2; // calls TImplClass.P2;
end;