本文根据 CandyCat 收藏的 《编程实现窗体的半透明效果（作者：罗蔷）》一文修改而成，供BCB+Win2000使用。
将控件安装即可使用
btw：分类里面，没有BCB，只好贴到delphi里面
////////////////////////////////////////////////////////////////////////////////////////////////
头文件：
//---------------------------------------------------------------------------
#ifndef TransparentFormH
#define TransparentFormH
//---------------------------------------------------------------------------
#include <SysUtils.hpp>
#include <Controls.hpp>
#include <Classes.hpp>
#include <Forms.hpp>
//---------------------------------------------------------------------------
class PACKAGE TTransparentForm : public TComponent
{
private:
protected:
int m_nAlphaValue;
HWND m_hParentFormHandle;
void __fastcall SetAlphaValue(int nAlpha);
void __fastcall UpdateDisplay();
public:
__fastcall TTransparentForm(TComponent* Owner);
__published:
__property int AlphaValue = {read = m_nAlphaValue, write = SetAlphaValue, default = 0};
};
//---------------------------------------------------------------------------
#endif
////////////////////////////////////////////////////////////////////////////////////////////////
cpp文件：
//---------------------------------------------------------------------------
#include <vcl.h>
#pragma hdrstop
#include "TransparentForm.h"
#pragma package(smart_init)
//---------------------------------------------------------------------------
// ValidCtrCheck is used to assure that the components created do not have
// any pure virtual functions.
//
static inline void ValidCtrCheck(TTransparentForm *)
{
new TTransparentForm(NULL);
}
//---------------------------------------------------------------------------
__fastcall TTransparentForm::TTransparentForm(TComponent* Owner)
: TComponent(Owner)
{
if (ComponentState.Contains(csDesigning))
return;
m_nAlphaValue = 255 ;
m_hParentFormHandle = ((TForm *)(Owner))->Handle ;
SetWindowLong(m_hParentFormHandle, GWL_EXSTYLE, GetWindowLong(m_hParentFormHandle, GWL_EXSTYLE) | WS_EX_LAYERED);
}
//---------------------------------------------------------------------------
namespace Transparentform
{
void __fastcall PACKAGE Register()
{
TComponentClass classes[1] = {__classid(TTransparentForm)};
RegisterComponents("Easysoft", classes, 0);
}
}
//---------------------------------------------------------------------------
void __fastcall TTransparentForm::SetAlphaValue(int nAlpha)
{
if (nAlpha >= 0 && nAlpha < 256)
{
m_nAlphaValue = nAlpha;
UpdateDisplay();
}
}
void __fastcall TTransparentForm::UpdateDisplay()
{
if (ComponentState.Contains(csDesigning))
return;
SetLayeredWindowAttributes(m_hParentFormHandle, 0, m_nAlphaValue, 2);
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//wei@shijun.com
//http://www.shijun.com
//5/19/2001