Delphi 为什么忽略加载的方法?
我想知道为什么,但我不能简单地调试我的简单程序。已加载的方法被忽略,它永远不会执行。不知道为什么。看:Delphi 为什么忽略加载的方法?,delphi,Delphi,我想知道为什么,但我不能简单地调试我的简单程序。已加载的方法被忽略,它永远不会执行。不知道为什么。看: TGridObj = class (TComponent) private FPen1:TPen; FBrush1:TBrush; FChange:TNotifyEvent; protected procedure Loaded; override; public constructor Create(AOwner: TComponent); override
TGridObj = class (TComponent)
private
FPen1:TPen;
FBrush1:TBrush;
FChange:TNotifyEvent;
protected
procedure Loaded; override;
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
published
property OnChange:TNotifyEvent read FChange write FChange;
property Pen1:TPen read FPen1 write FPen1;
property Brush1:TBrush read FBrush1 write FBrush1;
end;
。
.
。
只有从表单资源(dfm文件)加载组件时,才会执行Thanxonload 如果组件仅在运行时以代码创建,则不会执行 更新:
我建议设计组件,以便它们也可以在运行时创建和配置-这意味着我避免重写onload。优点是不需要包安装/组件注册
加载的
仅在组件的属性从表单文件流式传输时调用。因为您是在运行时创建它的,load
不会被调用。这是故意的
您的代码无论如何都需要做一些工作,以允许在运行时修改OnChange
事件,并将更改过滤到画笔和画笔。我会这样做:
TGridObj = class (TComponent)
private
FPen1: TPen;
FBrush1: TBrush;
FChange: TNotifyEvent;
procedure DoChange(Sender: TObject);
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
published
property OnChange: TNotifyEvent read FChange write FChange;
property Pen1: TPen read FPen1;
property Brush1: TBrush read FBrush1;
end;
constructor TGridObj.Create(AOwner: TComponent);
begin
inherited;
FPen1 := TPen.Create;
FPen1.OnChange := DoChange;
FBrush1 := TBrush.Create;
FBrush1.OnChange := DoChange;
end;
destructor TGridObj.Destroy;
begin
FBrush1.Free;
FPen1.Free;
inherited;
end;
procedure TGridObj.DoChange(Sender: TObject);
begin
if Assigned(FChange) then
FChange(Sender);
end;
现在不需要加载或类似的东西。因为在访问FChange
之前,您需要等待笔和画笔的OnChange
事件实际触发
顺便说一句,在代码中为修改底层字段的Pen1
和Brush1
添加属性设置器是错误的。这会导致泄漏和各种各样的混乱。另外,请注意,将笔和画笔公开为公共属性会允许TGridObj
的客户端更改OnChange
事件。这颠覆了TGridObj.OnChange
procedure TForm1.FormCreate(Sender: TObject);
begin
Grid:=TGridObj.Create(nil);
Grid.OnChange:=ev1.OnChange;
Form1.InsertComponent(Grid);
end;
TGridObj = class (TComponent)
private
FPen1: TPen;
FBrush1: TBrush;
FChange: TNotifyEvent;
procedure DoChange(Sender: TObject);
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
published
property OnChange: TNotifyEvent read FChange write FChange;
property Pen1: TPen read FPen1;
property Brush1: TBrush read FBrush1;
end;
constructor TGridObj.Create(AOwner: TComponent);
begin
inherited;
FPen1 := TPen.Create;
FPen1.OnChange := DoChange;
FBrush1 := TBrush.Create;
FBrush1.OnChange := DoChange;
end;
destructor TGridObj.Destroy;
begin
FBrush1.Free;
FPen1.Free;
inherited;
end;
procedure TGridObj.DoChange(Sender: TObject);
begin
if Assigned(FChange) then
FChange(Sender);
end;