我继承TPanel类，做一个ButtonPanel，想将BMP图像加进来，但是老报错。。。。

Question

下面的程序不知道能否实现，SetGlyph()和GetGlyph()方法是从TSpeedButton类中抄过来的，但是下面的程序编译时提示无法识别TButtonGlyph类，但是我Use了Buttons单元，为什么？？如果您知道怎么实现这个功能请您赐教！unit ButtonPanel;interfaceuses
  Windows, Messages, SysUtils, Classes, Controls,ExtCtrls,Buttons;type
  TButtonPanel = class(Tpanel)
  private
    FDown:Boolean;
    FGlyph: Pointer;
    Procedure  SetDown(Value:Boolean);
    function GetGlyph: TBitmap;
    procedure SetGlyph(Value: TBitmap);
    procedure GlyphChanged(Sender: TObject);
  protected
    { Protected declarations }
  public
   constructor Create(AOwner: TComponent); override;
   destructor Destroy; override;
  published
    Property  Down:Boolean Read FDown Write SetDown;
    property  Glyph: TBitmap read GetGlyph write SetGlyph;
  end;procedure Register;implementationprocedure Register;
begin
  RegisterComponents('SelfCom', [TButtonPanel]);
end;{ TButtonPanel }constructor TButtonPanel.Create(AOwner: TComponent);
begin
  FGlyph := TButtonGlyph.Create;
  TButtonGlyph(FGlyph).OnChange:=GlyphChanged;
  inherited;
  FDown :=True;
  Width :=50;
  Height:=40;
  BevelInner:= bvRaised;
  BevelOuter:= bvRaised;
  Caption:='ButtonPanel1';
end;function TButtonPanel.GetGlyph: TBitmap;
begin
  Result := TButtonGlyph(FGlyph).Glyph;
end;
    
procedure TButtonPanel.SetGlyph(Value: TBitmap);
begin
  TButtonGlyph(FGlyph).Glyph := Value;
  Invalidate;
end;procedure TButtonPanel.SetDown(Value:Boolean);
begin
   if Value then  begin
      BevelInner:= bvRaised;
      BevelOuter:= bvRaised;
   end
   else begin
      BevelInner:= bvLowered;
      BevelOuter:= bvLowered;
   end;
   FDown:=Value ;
end;
procedure TButtonPanel.GlyphChanged(Sender: TObject);
begin
    Invalidate;
end;destructor TButtonPanel.Destroy;
begin
  TButtonGlyph(FGlyph).Free;
  inherited;
end;end.

Answer 1

TButtonGlyph类是在Buttons单元中定义了的。

Answer 2

如何改造Panel，使他能够加入图像啊！！！！！！！！！

Answer 3

要Tpanel能画图不难
因为她没有Canvas，所以要创建一个TControlCanvas()对象
这个对象的Control:=Tpanel
然后就可以直接在这个你创建的画布上面画图了画完就会在Tpanel上看到

Answer 4

TButtonGlyph在Buttons的implementation之下，是访问不到了；可以试着改Buttons，或者把那些东西都加到你的TButtonPanel中，想是比较麻烦的；可用楼上的Canvas方法试试

Answer 5

谢谢各位，其实用Panel和Image融合在一起应该可以实现，但是，我做的还是不对，大家想想看怎么做。请给出源程序。

Answer 6

//正好有个简单的 看看是不是满足你的要求
unit uImagePanel;interfaceuses
  SysUtils, Classes, Controls, ExtCtrls,Windows,Graphics,Messages;type
  TImagePanel = class(TPanel)
  private
    { Private declarations }
    FBitmap:TBitmap;
    FBmpFileName: string;
    FStreatch: Boolean;
    FDisplayImageFileName: Boolean;
    procedure SetBmpFileName(const Value: string);
    procedure SetStreatch(const Value: Boolean);
    procedure SetDisplayImageFileName(const Value: Boolean);
  protected
    { Protected declarations }
    procedure Paint;override;
        procedure WMEraseBkgnd(var Message: TWmEraseBkgnd); message WM_ERASEBKGND;
  public
    { Public declarations }
  published
    { Published declarations }
    property BmpFileName:string read FBmpFileName write SetBmpFileName;
    property Streatch:Boolean read FStreatch write SetStreatch default False;
    property DisplayImageFileName:Boolean read FDisplayImageFileName write SetDisplayImageFileName default True;
  end;procedure Register;implementationprocedure Register;
begin
  RegisterComponents('Report', [TImagePanel]);
end;{ TImagePanel }procedure TImagePanel.SetBmpFileName(const Value: string);
begin
  FBmpFileName := Value;
  if FileExists(FBmpFileName) then
  begin
    if not Assigned(FBitMap) then
      FBitmap:=TBitmap.Create;
    FBitmap.LoadFromFile(FBmpFileName);
    Paint;
  end
  else
  begin
    FBitmap.Free;
    FBitmap:=nil;
    Paint;
  end;end;procedure TImagePanel.Paint;
var
  Rect:TRect;
begin
  //  if not Assigned(FBitmap) then
  begin
    inherited;
    Canvas.TextOut(0,0,'无图像');
    Exit;
  end;  Canvas.Lock;
  try    inherited;
    if FStreatch then
    begin      Rect.Left:=0;
      Rect.Top:=0;
      Rect.Bottom:=Height+Top;
      Rect.Right:=Width+Left;      //拉伸
      Canvas.StretchDraw(Rect,FBitmap);
    end
    else
    begin
      //不拉伸
      Canvas.Draw(0,0,FBitmap);
    end;
    if csDesigning in ComponentState then
    with Canvas do
    begin
      Canvas.Pen.Color:=clRed;
      if FDisplayImageFileName then
        Canvas.TextOut(0,0,PChar(FBmpFileName));
    end else
    begin
      if FDisplayImageFileName then
      Canvas.TextOut(0,0,PChar(FBmpFileName)) ;
    end;
  finally
    Canvas.Unlock;
  end;end;procedure TImagePanel.WMEraseBkgnd(var Message: TWmEraseBkgnd);
begin
  //强制重绘
  Paint;
  //由系统重绘
  //UpdateWindow(Handle);
end;procedure TImagePanel.SetStreatch(const Value: Boolean);
begin
  if FStreatch<> Value then
  begin
    FStreatch := Value;
    Paint;
  end;
end;procedure TImagePanel.SetDisplayImageFileName(const Value: Boolean);
begin
  if FDisplayImageFileName<> Value then
  begin
    FDisplayImageFileName := Value;
    Paint;
  end;
end;end.