如何制作半透明的窗体？

[czq7]

在Win2K+D6环境下可直接制作出半透明的窗体，并且其透明度可调，那么在Win2K+D5下有戏吗？

[li_zhifu]

type
TSetLayeredWindowAttributes = function (hwnd:HWND; crKey:Longint; bAlpha:byte; dwFlags:longint ):longint; stdcall;

var
Form1: TForm1;
SetLayeredWindowAttributes: TSetLayeredWindowAttributes = nil;

...

procedure InitProcs;
const
sUser32 = 'User32.dll';
var
ModH: HMODULE;
begin
ModH := GetModuleHandle(sUser32);
if ModH <> 0 then
@SetLayeredWindowAttributes := GetProcAddress(ModH, 'SetLayeredWindowAttributes');
end;

procedure TForm1.FormCreate(Sender: TObject);
var AStyle:Integer;
begin
InitProcs;
Alpha:=150;//0为完全透明，255完全不透明
AStyle := GetWindowLong(Handle, GWL_EXSTYLE);
if (AStyle and $00080000) = 0 then
SetWindowLong(Handle, GWL_EXSTYLE, AStyle or $00080000);
if assigned(SetLayeredWindowAttributes) then
SetLayeredWindowAttributes(Handle,0,Alpha,$2);
end;

用这种方法可以在Win2K中显示半透明的窗体，而在Win9X中不透明，但也不会报Dll错

[kuangning]

Unit TranForm; {DragonPC 2001.2.21}
Interface
Uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms ;
Type
TTranForm = class (TComponent)
Private
FAlphaValue: integer;
FParentFormHandle: HWND;
Procedure SetFAlphaValue (Alpha: integer);
Protected
Procedure UpdateDisplay;
Public
Constructor Create (AOwner: TComponent); override;
Published
Property AlphaValue: integer read FAlphaValue write SetFAlphaValue;
End;
Const
WS_EX_LAYERED = $80000;
LWA_ALPHA = 2;

Procedure Register;
Function SetLayeredWindowAttributes (Handle: HWND; COLORKEY: COLORREF;
Alpha: BYTE; Flags: DWORD): Boolean; stdcall; external 'USER32.DLL';
Implementation
Procedure Register;
Begin
RegisterComponents ('Standard', [TTranForm]);
End;
Procedure TTranForm.SetFAlphaValue (Alpha: integer);
Begin
if (Alpha >= 0) and (Alpha < 256) then begin
FAlphaValue:= Alpha;
UpdateDisplay ();
End;
End;
Procedure TTranForm.UpdateDisplay;
Begin
if (csDesigning in ComponentState) then Exit ;
SetLayeredWindowAttributes (FParentFormHandle, 0, FAlphaValue, 2);
End;
Constructor TTranForm.Create (AOwner: TComponent);
Begin
Inherited;
if (csDesigning in ComponentState) then Exit;
FAlphaValue:= 255;
FParentFormHandle:= TForm (AOwner). Handle;
SetWindowLong (FParentFormHandle,
GWL_EXSTYLE, GetWindowLong (FParentFormHandle, GWL_EXSTYLE) or WS_EX_LAYERED);
End;
End.

[czq7]

楼上的方法，我也试过，在9x下报错。我同意li_zhifu的方法。不过得谢谢楼上的解答！

[cdchq]

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