Memory management 如何在默认构造函数上使用智能指针
所以,我又一次在学习新东西,我遇到了聪明的指针。我有密码Memory management 如何在默认构造函数上使用智能指针,memory-management,constructor,delphi-xe2,smart-pointers,Memory Management,Constructor,Delphi Xe2,Smart Pointers,所以,我又一次在学习新东西,我遇到了聪明的指针。我有密码 procedure TForm3.BitBtn1Click(Sender: TObject); var _StringList: ISmartPointer<TStringList>; begin _StringList := TSmartPointer<TStringList>.Create(TStringList.Create); end; 正如您所看到的,变量声明有点奇怪,需要简化。我找到了另一个解
procedure TForm3.BitBtn1Click(Sender: TObject);
var
_StringList: ISmartPointer<TStringList>;
begin
_StringList := TSmartPointer<TStringList>.Create(TStringList.Create);
end;
正如您所看到的,变量声明有点奇怪,需要简化。我找到了另一个解决办法
procedure TForm3.btnDelphiClick(Sender: TObject);
var
_StringList: TStringList;
begin
_StringList := SmartGuard.SmartGuard<TStringList>(TStringList.Create(False));
end;
遗憾的是,它不适用于无参数构造函数
procedure TForm3.btnDelphiClick(Sender: TObject);
var
_StringList: TStringList;
begin
_StringList := SmartGuard.SmartGuard<TStringList>(TStringList.Create);
end;
[dcc32错误]Main.pas47:E2089类型转换无效
我在这里运气不好吗?
另外,我知道你们中的一些人会争辩说我应该坚持尝试……最后阻止,但这是出于好奇
unit SmartGuard;
interface
type
IGuard = interface
['{CE522D5D-41DE-4C6F-BC84-912C2AEF66B3}']
end;
TGuard = class(TInterfacedObject, IGuard)
private
FObject: TObject;
public
constructor Create(AObject: TObject);
destructor Destroy; override;
end;
SmartGuard<T: class> = record
private
FGuard: IGuard;
FGuardedObject: T;
public
class operator Implicit(GuardedObject: T): SmartGuard<T>;
class operator Implicit(Guard: SmartGuard<T>): T;
end;
implementation
uses
{Delphi}
System.SysUtils
{Project}
;
constructor TGuard.Create(AObject: TObject);
begin
FObject := AObject;
end;
destructor TGuard.Destroy;
begin
FObject.Free;
inherited;
end;
{ SmartGuard }
class operator SmartGuard<T>.Implicit(GuardedObject: T): SmartGuard<T>;
begin
Result.FGuard := TGuard.Create(GuardedObject);
Result.FGuardedObject := GuardedObject;
end;
class operator SmartGuard<T>.Implicit(Guard: SmartGuard<T>): T;
begin
Result := Guard.FGuardedObject;
end;
end.
我很想找到一个解决方案,它不需要像这里那样调用额外的方法,例如_StringList.Value.Add'foo';和特殊括号,如_StringList:=TSmartPointer.CreateTStringList.Create 编译器需要帮助消除歧义
TStringList.Create
编译器不知道这是对方法的引用还是对方法的调用
通过添加paren来消除歧义,表明这是一个调用
_StringList := SmartGuard.SmartGuard<TStringList>(TStringList.Create());