c# - Bitmap.FromHbitmap erroring when called over RDP -

our application cursor manipulation enable "relatively" nice drag drop animation on winforms (at time wpf wasn't option). when using application on rdp session throws generic gdi+ exception.

the method throws this:

[dllimport("user32")] private static extern bool geticoninfo(intptr hicon, out iconinfo piconinfo);  [dllimport("user32.dll")] private static extern intptr loadcursorfromfile(string lpfilename);  [dllimport("user32.dll", setlasterror = true)] public static extern bool destroyicon(intptr hicon);  [dllimport("gdi32.dll", setlasterror = true)] private static extern bool deleteobject(intptr hobject);  public static bitmap bitmapfromcursor(cursor cur) {     iconinfo iinfo;     geticoninfo(cur.handle, out iinfo);      bitmap bmp = bitmap.fromhbitmap(iinfo.hbmcolor);     deleteobject(iinfo.hbmcolor);     deleteobject(iinfo.hbmmask);      bitmapdata bmdata = bmp.lockbits(new rectangle(0, 0, bmp.width, bmp.height), imagelockmode.readonly, bmp.pixelformat);     bitmap dstbitmap = new bitmap(bmdata.width, bmdata.height, bmdata.stride, pixelformat.format32bppargb, bmdata.scan0);     bmp.unlockbits(bmdata);      return new bitmap(dstbitmap); } 

specifically line:

bitmap bmp = bitmap.fromhbitmap(iinfo.hbmcolor); 

when debugging hbmcolor 0, means when running on rdp call geticoninfo doesn't return required information.

i can check 0 , handle special case, there can make work on rdp normally?

edit

here's iconinfo structure:

[structlayout(layoutkind.sequential)] struct iconinfo {      public bool ficon;         // specifies whether structure defines icon or cursor. value of true specifies                     // icon; false specifies cursor.      public int32 xhotspot;     // specifies x-coordinate of cursor's hot spot. if structure defines icon, hot                     // spot in center of icon, , member ignored.      public int32 yhotspot;     // specifies y-coordinate of cursor's hot spot. if structure defines icon, hot                     // spot in center of icon, , member ignored.      public intptr hbmmask;     // (hbitmap) specifies icon bitmask bitmap. if structure defines black , white icon,                     // bitmask formatted upper half icon , bitmask , lower half                     // icon xor bitmask. under condition, height should multiple of two. if                     // structure defines color icon, mask defines , bitmask of icon.      public intptr hbmcolor;    // (hbitmap) handle icon color bitmap. member can optional if                     // structure defines black , white icon. , bitmask of hbmmask applied srcand                     // flag destination; subsequently, color bitmap applied (using xor)                     // destination using srcinvert flag. }         

from habjan's answer below i've added comments p/invoke structure above. looks hbmmask contains bitmap reference i'm after, i'm afraid bit manipulation skills rather rusty. when p/invoke says upper half / lower half - inferring to?

is possible black , white bitmap this?

i think due rdp color depth. if cursor black , white (via rdp), not hbmcolor value parameter optional.

msdn says:

hbmcolor  type: hbitmap 

description: handle icon color bitmap. member can optional if structure defines black , white icon. , bitmask of hbmmask applied srcand flag destination; subsequently, color bitmap applied (using xor) destination using srcinvert flag.

edit:

public static bitmap bitmapfromcursor(cursor cur) {     iconinfo iinfo;     geticoninfo(cur.handle, out iinfo);      bitmap bmpcolor = null;      if (iinfo.hbmcolor != intptr.zero) {        bmpcolor = bitmap.fromhbitmap(iinfo.hbmcolor);     }     else {        bmpcolor = new bitmap(w,h);        // fill bmpcolor white colour     }      bitmap bmpmask = bitmap.fromhbitmap(iinfo.hbmmask);     deleteobject(iinfo.hbmcolor);     deleteobject(iinfo.hbmmask);      // apply mask bitmap color bitmap:     // http://stackoverflow.com/questions/3654220/alpha-masking-in-c-sharp-system-drawing      bitmapdata bmdata = bmp.lockbits(new rectangle(0, 0, bmp.width, bmp.height), imagelockmode.readonly, bmp.pixelformat);     bitmap dstbitmap = new bitmap(bmdata.width, bmdata.height, bmdata.stride, pixelformat.format32bppargb, bmdata.scan0);     bmp.unlockbits(bmdata);      return new bitmap(dstbitmap); } 

... did not test code, it's give brief info do...