我有一个自定义控件：
type TContosoFrobber = class(TCustomControl) private end;
在内部,我的组件创建一个控件：
type
TContosoFrobber = class(TCustomControl)
private
FMyDateTimePicker: TDateTimePicker;
public
constructor Create(AOwner : TComponent); override;
property DateTimePicker: TDateTimePicker read FMyDateTimePicker;
end;
constructor TContosoFrobber.Create(AOwner: TComponent);
begin
inherted Create(AOwner);
FMyControl := TMyDateTimePicker.Create(AOwner);
end;
其中TMyDateTimePicker是TDateTimePicker的简单后代
TMyDateTimePicker = class(TDateTimePicker) protected end;
总结一下我做了什么：
>声明一个TDateTimePicker的私有变量
>将其公开为TDateTimePicker类型的公共(即未发布)属性
>通过多态,控件实际上是TDateTimePicker的后代
这一切都奏效 – 直到最近我重新安装Delphi XE6(在Windows 10上).
DFM
这就是我无法理解为什么我在设计时遇到错误的原因：
Class TMyDateTimePicker not found
为什么要找那个班？该类在实现细节中;它没有发布用于流式传输.流媒体系统甚至试图创建它！？所以我检查DFM：
object cfBeachBall: TContosoFrobber
Left = 445
Top = 25
Width = 101
Height = 22
...snip...
object TMyDateTimePicker
Left = 0
Top = 0
Width = 101
Height = 22
Date = 37306.581535243100000000
Time = 37306.581535243100000000
TabOrder = 0
TabStop = False
end
end
为什么TInternalDateTimePicker以dfm结尾：
>该物业是公开的,未公布
如何阻止表单流式传输系统在dfm中放置未发布的属性？
更糟糕的是有缺陷的IDE
object cfPlasticBag: TContosoFrobber
Left = 445
Top = 25
Width = 101
Height = 22
...snip...
object TMyDateTimePicker
Left = 0
Top = 0
Width = 101
Height = 22
Date = 37306.581535243100000000
Time = 37306.581535243100000000
TabOrder = 0
TabStop = False
end
object TMyDateTimePicker
Left = 0
Top = 0
Width = 101
Height = 22
Date = 37306.581535243100000000
Time = 37306.581535243100000000
TabOrder = 0
TabStop = False
end
end
>如何阻止dfm包含未发布的属性？
>我如何阻止dfm包含它两次？
黑客解决方法
我知道可怕的黑客攻击：告诉DFM控制它不应该让任何业务知道：
initialization
RegisterClass(TMyDateTimePicker);
finalization
UnRegisterClass(TMyDateTimePicker);
end.
现在dfm包含一个没有业务知道的控件.每次我保存表单时,它都会包含对不应该的内容的引用.最糟糕的是：我验证了它对TMyDateTimePicker的错误信念.
为什么Delphi XE6在重新安装之前没有这样做？也许我需要安装最新更新的长期以来不支持的Delphi版本？
已知错误？
解决方法
问题是您将错误的所有者分配给TDateTimePicker.您正在分配您的TContosoFrobber所有者而不是TContosoFrobber本身：
constructor TContosoFrobber.Create(AOwner: TComponent); begin inherted Create(AOwner); FMyControl := TMyDateTimePicker.Create(Self); // <-- not AOwner! end;
或者：正如Jerry Doge所提到的,你可以使用零所有者.你只需手动Free()TDataTimePicker：
type
TContosoFrobber = class(TCustomControl)
private
FMyDateTimePicker: TDateTimePicker;
public
constructor Create(AOwner : TComponent); override;
destructor Destroy; override;
...
end;
constructor TContosoFrobber.Create(AOwner: TComponent);
begin
inherted Create(AOwner);
FMyControl := TMyDateTimePicker.Create(nil);
end;
destructor TContosoFrobber.Destroy;
begin
FMyControl.Free;
inherted Destroy;
end;