我意识到 Delphi 不支持接口帮助器,但是在阅读了几个 SO 主题和 Spring4D 的源代码等资料后,我想知道是否有方法可以实现以下目标?源代码注释基本上概括了我试图做的事情,因此在此呈现:
program IHelper;
{$APPTYPE CONSOLE}
{$R *.res}
uses
Spring,
System.SysUtils;
type
IMyThing = interface
['{01E799A5-9141-4C5E-AA85-B7C9792024D9}']
procedure BasicThing;
end;
TMyThing = class(TInterfacedObject, IMyThing)
strict private
procedure BasicThing;
end;
IMyThingHelper = record
private
FOutage: IMyThing;
public
class operator Implicit(const Value: IMyThing): IMyThingHelper;
procedure HelpfulThing;
end;
TMyThingHelper = class helper for TMyThing
public
class procedure ObjectThing;
end;
{ TOutage }
procedure TMyThing.BasicThing;
begin
Writeln('Basic Thing');
end;
{ IOutageHelper }
procedure IMyThingHelper.HelpfulThing;
begin
Writeln('Helpful thing');
end;
class operator IMyThingHelper.Implicit(const Value: IMyThing): IMyThingHelper;
begin
Result.FOutage := Value;
end;
{ TMyThingHelper }
class procedure TMyThingHelper.ObjectThing;
begin
Writeln('Object thing');
end;
var
LThing: IMyThing;
begin
try
LThing := TMyThing.Create;
LThing.BasicThing;
//LThing.HelpfulThing; // <--- **** prefer this syntax but obviously does not compile
IMyThingHelper(LThing).HelpfulThing; // <--- this works ok but prefer not to have to cast it here
//LThing.ObjectThing; // <--- obviously does not compile
(LThing as TMyThing).ObjectThing; // <--- class helpers work ok but no good for interfaces
Readln;
except
on E: Exception do
Writeln(E.ClassName, ': ', E.Message);
end;
end.
任何关于如何使代码在 **** 显示的想法或建议?我知道答案可能是完全“不行”,但似乎有一些非常聪明的变通方法正在被实现,也许有人比我聪明知道怎么做?(Delphi XE5)另一个例子
var
dataObject: IDataObject;
//Get clipboard IDataObject
OleGetClipboard({out}dataObject);
//Check if they want us to move or copy what's on the clipboard
preferredDropEffect: DWORD := dataObject.GetPreferredDropEffect;
//...do the stuff with the clipboard
//Tell them what we did
dataObject.SetPerformedDropEffect(DROPEFFECT_NONE); //we moved the underlying data; sender need not do anything
dataObject.SetPasteSucceeded(DROPEFFECT_MOVE); //Paste complete
带有一个助手:
TDataObjectHelper = interface helper for IDataObject
public
function GetPreferredDropEffect(DefaultPreferredDropEffect: DWORD=DROPEFFECT_NONE): DWORD;
end;
function TDataObjectHelper.GetPreferredDropEffect(DefaultPreferredDropEffect: DWORD=DROPEFFECT_NONE): DWORD;
begin
{
DROPEFFECT_NONE = 0; //Drop target cannot accept the data.
DROPEFFECT_COPY = 1; //Drop results in a copy. The original data is untouched by the drag source.
DROPEFFECT_MOVE = 2; //Drag source should remove the data.
DROPEFFECT_LINK = 4; //Drag source should create a link to the original data.
DROPEFFECT_SCROLL = 0x80000000 //Scrolling is about to start or is currently occurring in the target. This value is used in addition to the other values.
}
if TDataObjectHelper.ContainsFormat(Source, CF_PreferredDropEffect) then
Result := TDataObjectHelper.GetUInt32(Source, CF_PREFERREDDROPEFFECT)
else
Result := DefaultDropEffect;
end;
IMyThing
的助手 接口。实现仍然可以是一个包装器,但在许多需要原接口的情况下,可以使用这样的派生接口。 - Rudy Velthuis