使用SetLayeredWindowAttributes API 实现透明窗口

//bAlpha form 0 to 255 //When bAlpha is 0, the window is completely transparent. //When bAlpha is 255, the window is opaque. BOOL SetWindowAlpha(HWND hwnd, BYTE bAlpha) { BOOL bRet = 0; HMODULE hModule = GetModuleHandle(_T("User32.dll")); if(hModule) { #ifndef WS_EX_LAYERED #define WS_EX_LAYERED 0x00080000UL #endif //WS_EX_LAYERED #ifndef LWA_ALPHA #define LWA_ALPHA 2 #endif typedef BOOL (WINAPI *pSETLAYEREDWINDOWATTRIBUTES)( HWND, COLORREF, BYTE, DWORD); pSETLAYEREDWINDOWATTRIBUTES pSetLayeredWindowAttributes = (pSETLAYEREDWINDOWATTRIBUTES)::GetProcAddress(hModule, "SetLayeredWindowAttributes"); if(pSetLayeredWindowAttributes) { // Set WS_EX_LAYERED on this window SetWindowLong(hwnd, GWL_EXSTYLE, GetWindowLong(hwnd, GWL_EXSTYLE) | WS_EX_LAYERED); // Make this window bAlpha pSetLayeredWindowAttributes(hwnd, 0, bAlpha, LWA_ALPHA); return bRet; } } return bRet; }