怎样让panel DBGrid 等元件 为透明

Question

怎样让panel DBGrid 等元件 为透明

Answer 1

unit Unit2;interfaceuses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls;type
  TTransPanel = class(TPanel)  private    ReEntry: Boolean;
    FOnPaint: TNotifyEvent;    procedure WMEraseBkgnd(var Message: TWmEraseBkgnd); message WM_ERASEBKGND;
    procedure WMWindowPosChanged(var Message: TWMWindowPosChanged);
                message WM_WINDOWPOSCHANGED;  protected    procedure CreateParams(var Params: TCreateParams); override;
    procedure Paint; override;  public    property Canvas;
    property OnPaint: TNotifyEvent read FOnPaint write FOnPaint;    constructor Create(AOwner: TComponent); override;
    procedure Invalidate; override;  end;implementationconstructor TTransPanel.Create(AOwner: TComponent);
begin
  inherited;
  with Canvas do begin
    Pen.Color := clHighlight;
    Pen.Style := psDot;
    Brush.Style := bsClear;
  end;
  ControlStyle := ControlStyle - [csCaptureMouse, csOpaque,
                                  csClickEvents, csDoubleClicks,
                                  csReflector, csMenuEvents,
                                  csNoStdEvents];
end;procedure TTransPanel.CreateParams(var Params: TCreateParams);
begin
  Params.ExStyle := Params.ExStyle or WS_EX_TRANSPARENT;
  inherited CreateParams(Params);
end;procedure TTransPanel.WMEraseBkgnd(var Message: TWmEraseBkgnd);
var
  rc: TRect;
  OrgDesignMode: Boolean;
  rgn: THandle;
  i: Integer;
begin
  rgn := CreateRectRgn(0, 0, Width, Height);
  try
    for i := Parent.ControlCount-1 downto 0 do
      if Parent.Controls[0] = Self then
        SelectClipRgn(Canvas.Handle, rgn);
  finally
    DeleteObject(rgn);
  end;  if ReEntry then exit;
  ReEntry := True;
  OrgDesignMode := csDesigning in ComponentState;
  try
    SetDesigning(False);
    Visible := False;
    rc := BoundsRect;
    InvalidateRect(Parent.Handle, @rc, False);
    UpdateWindow(Parent.Handle);
    Visible := True;
  finally
    SetDesigning(OrgDesignMode);
    ReEntry := False;
    Message.Result := 0;
  end;
end;procedure TTransPanel.WMWindowPosChanged(var Message:
  TWMWindowPosChanged);
begin
  inherited;
  if HandleAllocated then begin
    InvalidateRect(Handle, nil, True);
    UpdateWindow(Handle);
  end;
end;procedure TTransPanel.Paint;
begin
  if Assigned(OnPaint) then OnPaint(Self);
end;procedure TTransPanel.Invalidate;
begin
  if HandleAllocated then Perform(WM_ERASEBKGND, 0, 0);
end;end.