SystemParametersInfo

Hi.

can anyone please help me find out why this code doesn't work:
char* nextWpName = "mypic.jpg"
SystemParametersInfo (SPI_SETDESKWALLPAPER,0,nextWpName,SPIF_UPDATEINIF ILE);

my wallpaper simply disappears and goes blank.
help...
:(

From msdn:

Quote:

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...To specify a wallpaper bitmap, set pvParam to point to a null-terminated string containing the name of a bitmap file....

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So try it with a bitmap and not a jpeg.

If you wish to use JPEGS or GIFS (as the system does when you change wallpaper manually), you need to roll your sleeves up and use a COM interface - IActiveDesktop

This code opens a dialog allowing you to shose a BMP,GIF or JPEG......then it sets that as wallpaper and stretches it accross the screen...unfortunately, it is targetted at VC++...if you use a different compiler, come back and I will try again

Code:

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#include <windows.h>//Essential stuff
#include <wininet.h>//This has to be here...bug!!!!!!
#include <shlobj.h>//For IActiveDesktop
#include <comdef.h>//For neat VC++ COM Classes


struct COM_INIT{//To manage COM
        COM_INIT(){CoInitialize(0);}
        ~COM_INIT(){CoUninitialize();}
}COM_INIT_;


int WINAPI WinMain(HINSTANCE hInst,HINSTANCE,LPSTR,int){
       
        char szFile[MAX_PATH+1] = {0};
        OPENFILENAME ofn = {sizeof(OPENFILENAME)};
        ofn.hInstance = GetModuleHandle(0);
        ofn.lpstrFilter = "BMP\0*.BMP\0JPeg\0*.JPG\0Gif\0*.GIF\0";
        ofn.lpstrFile = szFile;
        ofn.nMaxFile = MAX_PATH+1;
        ofn.lpstrTitle = "Pick Bitmap, JPeg or Gif to replace wallpaper";

        if(!GetOpenFileName(&ofn))return 0;

        try{
               
                WALLPAPEROPT wpo = {sizeof(wpo),WPSTYLE_STRETCH};
                _com_ptr_t<_com_IIID<IActiveDesktop,
                        &__uuidof(IActiveDesktop)> > lpIAD;

                lpIAD.CreateInstance(CLSID_ActiveDesktop);       

                lpIAD->SetWallpaper(_bstr_t(szFile),0);

                lpIAD->SetWallpaperOptions(&wpo,0);

                lpIAD->ApplyChanges(AD_APPLY_ALL);


                MessageBox(0,"Wallpaper changed","",MB_OK);

        }
        catch(_com_error& e){
                MessageBox(0,(e.Description().length() ?
                        e.Description() : "COM Error"),0,MB_OK);
        }

        return 0;
}

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