透明输入框

unit fskinTranEdit;


interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls;
 
const
  TMWM__SpecialInvalidate = WM_USER + 1111;

type
  TSkinEdit = class(TEdit)
  private
    FClarity   : Boolean;
    procedure SetClarity(const Value: Boolean);
    { Private declarations }
  protected
    { Protected declarations }
    procedure CMEraseBkgnd     (var Message: TWMEraseBkgnd);    Message WM_ERASEBKGND;
    procedure WMSetText        (var Message: TWMSetText);
    procedure SpecialInvalidate(var Message: TMessage);         message TMWM__SpecialInvalidate;
    procedure CNCTLCOLOREDIT   (var Msg: TWMCTLCOLOREDIT);  message CN_CTLCOLOREDIT;
    procedure WMKeyDown        (var Message: TWMKeyDown);       message WM_KEYDOWN;
    procedure WMKillFocus      (Var Message: TWMKillFocus);     Message WM_KillFocus;
    procedure WMLButtonDown    (Var Message: TWMLButtonDown);   Message WM_LButtonDown;
    procedure WMMove           (Var Message: TWMLButtonDown);   Message WM_Move;
    procedure WMMouseMove      (Var Message: TWMMouseMove);     Message WM_MouseMove;
    procedure CreateParams(var Params: TCreateParams); override;
    procedure CreateWnd; override;
  public
    { Public declarations }
    constructor Create(AOwner: TComponent); override;
    procedure   Invalidate; override;
  published
    { Published declarations }
    property    Clarity:Boolean read FClarity write SetClarity default True;
    property BevelKind   default BKFlat;
    property BorderStyle default bsNone;
  end;

procedure Register;

implementation

procedure Register;
begin
  RegisterComponents('Sa', [TSkinEdit]);
end;

{ TClarityEdit }
procedure TSkinEdit.CMEraseBkgnd(var Message: TWMEraseBkgnd);
begin
  if Clarity then
    Message.Result := 1;
end;

procedure TSkinEdit.CNCTLCOLOREDIT(var Msg: TWMCTLCOLOREDIT);
begin
  if Clarity then
   with msg do
    begin
      SetTextColor(ChildDC, Font.Color);
      SetBkMode(ChildDC, Windows.TRANSPARENT);
      Result:=GetStockObject(HOLLOW_BRUSH);
    end
   else inherited;
end;

constructor TSkinEdit.Create(AOwner: TComponent);
begin
  inherited create(AOwner);
  self.BorderStyle:=bsNone;
  self.BevelKind:=bkflat;
  Clarity:= True;
end;

procedure TSkinEdit.CreateParams(var Params: TCreateParams);
begin
  inherited CreateParams(Params);
  if (CsDesigning in ComponentState) then exit;
  with Params do
  begin
    ExStyle:=ExStyle or WS_EX_TRANSPARENT;
  end;
end;

procedure TSkinEdit.CreateWnd;
begin
  inherited CreateWnd;
  if Clarity then
  begin
    SetWindowLong(Parent.Handle, GWL_STYLE,
      GetWindowLong(Parent.Handle, GWL_STYLE) and not WS_CLIPCHILDREN);
  end;
end;

procedure TSkinEdit.Invalidate;
begin
  if Clarity then PostMessage(Handle,TMWM__SpecialInvalidate,0,0)
    else inherited;
end;

procedure TSkinEdit.SetClarity(const Value: Boolean);
begin
  FClarity := Value;
end;

procedure TSkinEdit.SpecialInvalidate(var Message: TMessage);
var
  rect:TRect;
begin
  if Parent<>nil then
  begin
    rect:=ClientRect;
    rect.TopLeft:=Parent.ScreenToClient(ClientToScreen(rect.TopLeft));
    rect.BottomRight:=Parent.ScreenToClient(ClientToScreen(rect.BottomRight));
    InvalidateRect(Parent.Handle,@rect,true);
    RedrawWindow(Handle,nil,0,RDW_FRAME+RDW_INVALIDATE)
  end;
end;

procedure TSkinEdit.WMKeyDown(var Message: TWMKeyDown);
begin
  SendMessage(Handle,TMWM__SpecialInvalidate,0,0);
  inherited;
  PostMessage(Handle,TMWM__SpecialInvalidate,0,0);
end;

procedure TSkinEdit.WMKillFocus(var Message: TWMKillFocus);
begin
  inherited;
  if not (csDesigning in ComponentState) then
    PostMessage(Handle,TMWM__SpecialInvalidate,0,0)
end;

procedure TSkinEdit.WMLButtonDown(var Message: TWMLButtonDown);
begin
  inherited;
  if not (csDesigning in ComponentState) then
    PostMessage(Handle,TMWM__SpecialInvalidate,0,0);
end;

procedure TSkinEdit.WMMouseMove(var Message: TWMMouseMove);
begin
  inherited;
  if not (csDesigning in ComponentState) then
    PostMessage(Handle,TMWM__SpecialInvalidate,0,0);
end;

procedure TSkinEdit.WMMove(var Message: TWMLButtonDown);
begin
  inherited;
  //if not (csDesigning in ComponentState) then
    PostMessage(Handle,TMWM__SpecialInvalidate,0,0);
end;

procedure TSkinEdit.WMSetText(var Message: TWMSetText);
begin
  inherited;
  if not (csDesigning in ComponentState) then
    PostMessage(Handle,TMWM__SpecialInvalidate,0,0);
end;



end.

 procedure HandleCTLColorEdit(var Msg: TWMCTLCOLOREDIT);message WM_CTLCOLOREDIT;

procedure TForm1.Button2Click(Sender: TObject);
var
  BMP: TBitmap;
begin
  BMP := TBitmap.Create;
  BMP.LoadFromFile('C:\Documents and Settings\Administrator\桌面\未命名.bmp');
  Memo1.Brush.Bitmap := BMP;
  Memo1.Repaint;
  Bmp.Free;
end;

procedure TForm1.HandleCTLColorEdit(var Msg: TWMCTLCOLOREDIT);
begin
  if Msg.ChildWnd = Memo1.Handle then begin
    SetBkMode(Msg.ChildDC, TRANSPARENT);
    Msg.Result := Memo1.Brush.Handle;
  end;

end;