c# - SetFileTime returning error code 5 -

i trying p/invoke setfiletime, can't seem work. returns error code of 5 me (access denied), , not sure why. here code using:

void main() {     var pointer = createfile(@"c:\users\user\desktop\new folder\new text document.txt", fileaccess.readwrite, fileshare.none, intptr.zero, filemode.open, fileattributes.normal, intptr.zero);     console.writeline(pointer);     var = datetime.now.tofiletime();     long lpcreationtime = now;     long lplastaccesstime = now;     long lplastwritetime = now;     if (!setfiletime(pointer, ref lpcreationtime, ref lplastaccesstime, ref lplastwritetime))         console.writeline(getlasterror());     closehandle(pointer); }  [dllimport("kernel32.dll")] static extern uint32 getlasterror();  [dllimport("kernel32.dll", setlasterror = true)] static extern boolean setfiletime(intptr hfile, ref long lpcreationtime, ref long lplastaccesstime, ref long lplastwritetime);  [dllimport("kernel32.dll", setlasterror = true)] static extern boolean closehandle(intptr hobject);  [dllimport("kernel32.dll", charset = charset.unicode, setlasterror = true)] static extern intptr createfile(string filename, [marshalas(unmanagedtype.u4)] fileaccess fileaccess, [marshalas(unmanagedtype.u4)] fileshare fileshare, intptr securityattributes, [marshalas(unmanagedtype.u4)] filemode creationdisposition, [marshalas(unmanagedtype.u4)] fileattributes flags, intptr template); 

my pointer valid (2376) see setfiletime has failed , has returned error code of 5 (access denied). now, have ensured running administrator , account has permissions path, still, no cigar. have ideas why happening?

update

marshal.getlastwin32error() returns 5 after call setfiletime. also, need making call work can setfiletime on long paths in windows, createfile supports, current file libraries of .net not support long paths in windows.

from documentation of setfiletime:

a handle file or directory. handle must have been created using createfile function file_write_attributes access right.

your code doesn't manage that. .net fileaccess enumeration not compatible win32 access flags. you'll need define enum use createfile. likewise use of fileshare , filemode not correct.

this p/invoke declaration should suffice: http://www.pinvoke.net/default.aspx/kernel32.createfile

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as alexei said, don't call getlasterror because may picking error code framework call rather true error. use setlasterror = true , marshal.getlastwin32error().

you fail check errors in return value if createfile.