通过TObject.GetInterface可以获得对象的实例实现某个接口，前提条件是必须实例化对象后才能运行GetInterface
下面的方法可获取类是否实现了某个接口，并返回接口的偏移：
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function FindInterface(AClass: TClass; GUID:TGUID; var Offset:NativeInt):Boolean;
var i : integer;
InterfaceTable: PInterfaceTable;
InterfaceEntry: PInterfaceEntry;
begin while Assigned(AClass) do
begin
InterfaceTable := AClass.GetInterfaceTable;
if Assigned(InterfaceTable) then
begin
for i := 0 to InterfaceTable.EntryCount-1 do
begin
InterfaceEntry := @InterfaceTable.Entries[i];
if InterfaceEntry.IID=GUID then
begin
Offset:=InterfaceEntry.IOffset;
Exit(True);
end;
end;
end;
AClass := AClass.ClassParent;
end;
end;
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下面我们看下通过偏移量的快速获得对象的接口，以及通过接口快速获取对象：
快速获取对象的接口：
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type TSomeObject=class(TXXX, ISomeInterface)
......
end;
var FItemObjectOffset:NativeInt;
//获取偏移量FindInterface(TSomeObject, ISomeInterface, FItemObjectOffset)var P:TSomeObject;
Intf:ISomeInterface;
....................................//通过对象直接获取接口 PNativeInt(@Intf)^:=PNativeInt(@P)^+ FItemObjectOffset;
Intf._AddRef;
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快速通过接口获取对象
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type TSomeObject=class(TXXX, ISomeInterface)
......
end;
var FItemObjectOffset:NativeInt;
//获取偏移量FindInterface(TSomeObject, ISomeInterface, FItemObjectOffset)var P:TSomeObject;
Intf:ISomeInterface;
....................................//通过接口获取对象 P:=TSomeObject(Pointer(PNativeInt(@Intf)^- FItemObjectOffset));
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https://www.cnblogs.com/hezihang/p/5735897.html