消息的问题， 是不是一个控件只有一个wm_paint消息响应，如果窗体上多个相同控件间的消息wm_paint是否会相互影响

Question

不可能吧？
消息是通过句丙传播的，除非你设置的句丙是form1或者application
它向下扩散到其他构件了

Answer 1

unit MyPanel;interfaceuses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  ExtCtrls,grids;type
  TMyPanel = class(TPanel)
  private
    { Private declarations }
    FDown:boolean;
    FPaintStyle:Integer;
    FKind:Integer;
    FOnMouseEnter: TNotifyEvent;
    FOnMouseLeave: TNotifyEvent;
    OldWndProcPnl: TWndMethod;
    FOnPaint: TNotifyEvent;
    procedure SetDown(Value:boolean);
    procedure SetPaintStyle(Value:Integer);
    procedure SetKind(value:Integer);
  protected
    { Protected declarations }
    procedure CMMouseEnter(var Message: TMessage); message CM_MouseEnter;
    procedure CMMouseLeave(var Message: TMessage); message CM_MouseLeave;
    procedure Paint;override;
  public
    { Public declarations }
    procedure DrawBright(ACanvas:TCanvas;Arect:trect);
    procedure DrawGray(ACanvas:TCanvas;Arect:trect);
    procedure DrawCenterBright(ACanvas:TCanvas;Arect:trect);
    procedure DrawCenterGray(ACanvas:TCanvas;Arect:trect);
    procedure DrawCancel(ACanvas:TCanvas;Arect:trect);
    procedure DrawClear(ACanvas:TCanvas;Arect:trect);
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
   published
    { Published declarations }
    property OnMouseEnter: TNotifyEvent read FOnMouseEnter write FOnMouseEnter;
    property OnMouseLeave: TNotifyEvent read FOnMouseLeave write FOnMouseLeave;
    property Onpaint:TNotifyEvent read FOnPaint write FOnpaint;
    Property IsDown:boolean read FDown write SetDown;
    property PaintStyle:Integer read FPaintStyle write SetPaintStyle;
    property Kind:Integer read FKind write SetKind;
  end;procedure Register;implementationprocedure Register;
begin
  RegisterComponents('Samples', [TMyPanel]);
end;{ TMyPanel }
procedure TMyPanel.CMMouseEnter(var Message: TMessage);
begin
 if Assigned(FOnMouseEnter) then FOnMouseEnter(self);
end;procedure TMyPanel.CMMouseLeave(var Message: TMessage);
begin
 if Assigned(FOnMouseLeave) then FOnMouseLeave(self);
end;procedure TMyPanel.SetDown(Value: boolean);
begin
  if FDown<>Value then
  FDown:=Value;
end;procedure TMyPanel.SetKind(value: Integer);
begin
  if FKind<>Value then FKind:=Value;
end;procedure TMyPanel.Paint;
begin
  inherited Paint;
  case self.FPaintStyle of
   0:  DrawClear(TDrawGrid(self).canvas,self.ClientRect);//空白 ;
   1:  DrawBright(TDrawGrid(self).canvas,self.ClientRect);
   2:  DrawGray(TDrawGrid(self).canvas,self.ClientRect);
   3:  DrawCenterBright(TDrawGrid(self).canvas,self.ClientRect);
   4:  DrawCenterGray(TDrawGrid(self).canvas,self.ClientRect);
   5:  DrawCancel(TDrawGrid(self).canvas,self.ClientRect);
  else
       DrawClear(TDrawGrid(self).canvas,self.ClientRect);//空白
  end;end;procedure TMyPanel.SetPaintStyle(Value: Integer);
begin
  if FPaintStyle<>Value then
  FPaintStyle:=Value;
end;
//--------------
procedure TMyPanel.DrawBright(ACanvas:TCanvas;Arect:trect);
procedure TMyPanel.DrawGray(ACanvas: TCanvas; Arect: trect);
procedure TMyPanel.DrawCenterBright(ACanvas: TCanvas; Arect: trect);
procedure TMyPanel.DrawCenterGray(ACanvas: TCanvas; Arect: trect);
procedure TMyPanel.DrawCancel(ACanvas: TCanvas; Arect: trect);
procedure TMyPanel.DrawClear(ACanvas: TCanvas; Arect: trect);
//-------------------------------------------------------------------
constructor TMyPanel.Create(AOwner: TComponent);
begin
  inherited;
  PaintStyle:=0;
end;destructor TMyPanel.Destroy;
begin
  inherited;
end;end.

Answer 2

代码就是这么点，我现在是下面一个panel, 上面两个panel, 动态创建， 就是会出问题