[fpc-pascal] Getting multiple files from GetOpenFileNameA

James Richters james at productionautomation.net
Thu May 23 18:09:53 CEST 2019


I’m not clear about when they need one #0 or two.  I thought it was just .lpstrFile to make it clear there weren’t more file names in it.. so one #0 between each name and double #0 at the end.. maybe they all need double #0 at the end?

 

James

 

From: fpc-pascal <fpc-pascal-bounces at lists.freepascal.org> On Behalf Of Alexander Grotewohl
Sent: Thursday, May 23, 2019 11:56 AM
To: FPC-Pascal users discussions <fpc-pascal at lists.freepascal.org>
Subject: Re: [fpc-pascal] Getting multiple files from GetOpenFileNameA

 

I did notice lpstrFilter is terminated by one #0 instead of two. Other than that not at a pc to test.

--
Alexander Grotewohl
http://dcclost.com

 

On May 23, 2019 7:52 AM, James Richters <james at productionautomation.net <mailto:james at productionautomation.net> > wrote:

I have put together a program that demonstrates the issue I am having.  I have re-structured it a bit to try to make it more clear where the problem is.

While putting this together, I was able to get it to run fine with no problems if I did not try to put GetOpenFileNameA back to the directory of the last file I processed. Including a file sent in as a parameter.   If I set Open_File.lpstrFile:=Pchar(Target_File+#0+#0); where Target_File is the complete path and file name of the last file I processed,  If I select only one file, then the next time around it DOES work.. and will put me in the directory of Target_File and will show the filename of Target_File as a default, but if I select more than one file, the next time around, it crashes.. I have detailed the crash information in the sameple program comments.

Another way I wish to run this is to leave Open_File.lpstrFile alone and use Open_File.lpstrInitialDir to put me in the directory of the last processed file, but not specify a default filename.  I can’t get this to work correctly at all, but if I use Open_File.lpstrInitialDir without Open_File.lpstrFile then it does not crash,  I am just not put in the directory I expect to be in.  

 

Any Advice or suggestions on any of this, or on how I could improve the structure or methods of this program are greatly appreciated.

 

James

 

 

 

{$mode objfpc}{$H+}

//   https://docs.microsoft.com/en-us/windows/desktop/api/commdlg/nf-commdlg-getopenfilenamea

//   https://docs.microsoft.com/en-us/windows/desktop/api/commdlg/ns-commdlg-tagofna

Uses

  sysutils,Windows,Commdlg,Classes,CRT;

Var

Open_File          : TOpenFileNameA;

ret                : array[0..100000] of char;

Filenum            : Word;

Target_File        : AnsiString;

File_Stringlist    : tstringList;

{=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=}

Procedure Display_File_StringList(Var Display_String_List:tStringList);

Var

  SL_Loop : Word;

Begin

   If Display_String_List.Count=0 then

      Begin

         Textcolor(12);

         Writeln('0 Files Selected')

      End

   Else

   If Display_String_List.Count=1 then

      Begin

         TextColor(10);

         Writeln(Display_String_List[0]);

         Textcolor(14);

         Writeln('1 Files Selected');

      End

   Else

      Begin

         TextColor(13);

         Writeln('Path for all files: ',Display_String_List[0]);

         TextColor(10);

         For SL_Loop:= 1 to Display_String_List.Count-1 Do

            Writeln('File #',SL_Loop,': ',Display_String_List[SL_Loop]);

         Textcolor(14);

         Writeln(Display_String_List.Count-1,' Files Selected');

      End;

End;

{=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=}

Function Get_Files_Into_Stringlist(Var String_List:tStringList):Boolean;

Var

   Open_File_Result      : Boolean;

   Position_of_Filename  : Word;

Begin

   String_List.Clear;

   Open_File_Result:=GetOpenFileNameA(@Open_File);

   If Open_File_Result then

      Begin

         Position_of_Filename:=0;

         Repeat

            String_List.add(StrPas(@Open_File.lpstrFile[Position_of_Filename]));

            inc(Position_of_Filename,length(String_List[String_List.Count-1])+1);

         Until Open_File.lpstrFile[Position_of_Filename]=#0;

      End;

   Writeln(Open_File_Result);

   Get_Files_Into_Stringlist:=Open_File_Result;

End;

{=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=}

Procedure Process_File(Some_File: AnsiString);

Begin

   TextColor(11);

   Writeln('Processing File: ',Some_File);

End;

{=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=}

Begin {Main Program}

   fillchar(Open_File, sizeof(Open_File), 0);

   fillchar(ret, sizeof(ret), 0);

   Open_File.lStructSize:=sizeof(Open_File);

   Open_File.hwndOwner:=0;

   Open_File.lpstrFile:=ret;

   Open_File.lpstrFile[0]:=#0;

   Open_File.nMaxFile:=100000;

   Open_File.Flags := OFN_EXPLORER or OFN_FILEMUSTEXIST or OFN_ALLOWMULTISELECT;

   Open_File.lpstrDefExt:='.txt';

   Open_File.lpstrTitle:='My Program - Open File';

   Open_File.lpstrFilter:='All Files (*.*)'+#0+'*.*'+#0;

   File_Stringlist:=TStringlist.Create;

   If paramstr(1)<>'' then

      Begin

         Target_File:=paramstr(1);

         Process_File(Target_File);

      End

   else

      Target_File:='';

   Repeat

      If Target_File<>'' then

         Begin

            // The following line seems to cause my program to crash.

            // It does seem to work as I expect.  It puts me in the directory

            // of the file and shows the file name, but for some reason if I select

            // more than one file than I get

            // An unhandled exception occurred at $0040B428:

            // EAccessViolation:

            // $0040B428

            // $0040A03D

            // $00414447

            // $0040AE1E

            // $0040A03D

            // $00414447

            // $0040AE1E

            // $0040A03D

            // $00414447

            // $0040AE1E

            // $0040A03D

            // $00414447

            // $0040AE1E

            // $0040A03D

            // $00414447

            // $0040AE1E

            // $0040A03D

            // in a repeating loop if I use the command with two #0 at the end of

            // Open_File.lpstrFile:=Pchar(Target_File+#0+#0);

            

            // Or I get:

            // EAccessViolation: An unhandled exception occurred at $0040BB56:

            // with an exit code of 253

            // or 

            // An unhandled exception occurred at $0040BDD2:

            // EAccessViolation: Access violation

            // $0040BDD2

            // with an exit with a code 217

            // if I use one #0 at the end of

            // Open_File.lpstrFile:=Pchar(Target_File+#0);

            

            // these errors seem to show up more if I select multiple files or 

            // change directories.  

            Open_File.lpstrFile:=Pchar(Target_File+#0);

            

            

            // If I leaved the above commented out, then I should be able to use the 

            // command below to just put me in the directory specified, but with no default file

            // This does not work the way I expect it to work at all.

            // It does not put me into the directory of the file used as a parameter, it

            // Then for other files it puts me one level before the one I was just in

            // I want to be back where I was.  If I give it a parameter, I want to 

            // be in the directory of the file the parameter specifies, and then

            // I want to be in the directory of the previous file.

            // This just is not working the way I expect but does not cause any crash.

            Open_File.lpstrInitialDir:=Pchar(ExtractFilePath(Target_File)+#0+#0);

         End;

      Get_Files_Into_Stringlist(File_Stringlist);

      Display_File_StringList(File_Stringlist);

      If (File_Stringlist.Count=1) and FileExists(File_Stringlist[0]) Then

         Begin

            Target_File:=File_Stringlist[0];

            Process_File(Target_File);

         End

      Else

      If (File_Stringlist.Count>1) Then

         Begin

            Filenum:=0;

            Repeat

               Inc(Filenum);

               If (Filenum<File_Stringlist.Count) Then

                  Begin

                     Target_File:=File_Stringlist[0];

                     If Target_File[Length(Target_File)]<>'\' Then

                        Target_File:=Target_File+'\';

                     Target_File:=Target_File+File_Stringlist[Filenum];

                     Process_File(Target_File);

                  End;

            Until Filenum>=File_Stringlist.Count;

         End;

   Until File_Stringlist.count=0;

   File_Stringlist.Free;

end.

{=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=+=-=}

 

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