c# - Can't open file with DevIL -

here code:

 public void loadtexture(string textureid, string path)     {         int devilid = 0;         il.ilgenimages(1, out devilid);         il.ilbindimage(devilid); // set active texture          if (!il.illoadimage(path))         {             system.diagnostics.debug.assert(false, "could not open file, [" + path + "].");         }         // files we'll using need flipped before passing opengl         ilu.iluflipimage();         int width = il.ilgetinteger(il.il_image_width);         int height = il.ilgetinteger(il.il_image_height);         int openglid = ilut.ilutglbindteximage();          system.diagnostics.debug.assert(openglid != 0);         il.ildeleteimages(1, ref devilid);          _texturedatabase.add(textureid, new texture(openglid, width, height));     } 

i getting assertion failed, not open file [face.tif] error. made sure face.tif file in project folder, solution folder, bin folder, bin\debug folder still can't open it.

i'm trying follow book c# game programming serious game creation.

it looking file face.tif in same directory code running.

what setting path being passed method loadtexture?