Komponente CheckBox: Haken übermalen mit WMPaint

[bitsetter]

Hi,

anstatt WM_PAINT könntest du auch CN_DRAWITEM nehmen.
Noch ein bisschen unfertiger Code, aber zur Demonstration reicht es:

Delphi-Quellcode:

type
  TChBox = class(TCheckBox)
  protected
    procedure CNDrawItem(var Message: TWMDrawItem); message CN_DRAWITEM;
    procedure CreateWnd; override;
  end;

procedure TChBox.CNDrawItem(var Message: TWMDrawItem);
var
  Canv: TCanvas;
  CheckRect: TRect;
begin
  CheckRect := Message.DrawItemStruct.rcItem;
  CheckRect.Right := CheckRect.Bottom;
  Canv := TCanvas.Create;
  try
    Canv.Handle := Message.DrawItemStruct.hDC;
    //if  Message.DrawItemStruct.ItemState and ODS_SELECTED <> 0 then
    if Self.Checked then
      Canv.Brush.Color := clRed
    else
      Canv.Brush.Color := clWhite;
    Canv.Rectangle(CheckRect);
    Canv.Brush.Style := bsClear;
    Canv.TextOut(CheckRect.Right + 2,(CheckRect.Bottom - Canv.TextHeight(Caption)) div 2, Caption);
  finally
    Canv.Free;
  end;
end;

procedure TChBox.CreateWnd;
begin
  inherited CreateWnd;
  if HandleAllocated then
    SendMessage(Handle, BM_SETSTYLE, BS_CHECKBOX or BS_OWNERDRAW, 1);
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  Cb: TChBox;
begin
  Cb:= TChBox.Create(self);
  Cb.Parent:= self;
  Cb.Caption:= 'Test';
  Cb.Left:= 20;
  Cb.Top:= 50;
end;