Why is it locked?

Hello,

I have created a static C++ DLL and exported a function on it. The function creates a .gif file. I then interface the DLL in my C# project and I call the C++ function through C++.
I view the .gif file that has been created in a pictureBox. When I clear the pictureBox and try to view the .gif, an NullPointerException is thrown!
When I try to delete the .gif file manulaly, it says that another process is using the .gif file.
I figured that MyC#Project.exe is the one locking my .gif :(

Is there a way to be able to view .gif, clear them, and then view them again in the pictureBox?

Help Gurus!!

Ali

Sounds to me like the file handle is being kept open - i.e. whichever code you're using to write the .gif isn't closing the file handle after it's finished.

Darwen.

hi, how are you trying to create the gif file?

any information you can give me on creating gif files would be off great use?

Hi djing1985,

I am using an open source library called GUIDO. There is a function to convert GUIDO music notation files (.gmn) to (.gif) files. You can use some functions in the library that are responsible of drawing the .gif file. I don't thik it is a "clean" way of getting what you want.

Anyways, here is the link:
http://sourceforge.net/projects/guidolib/

It is in C++ by the way.
Good Luck!
Ali

ok cool thanks, i think your right though prob not what i want.

Hello Darwen,

I finished checking all the fclose commands and everything is there! The .gif file is first drawn in the memory and then thrown into a file. Again, I am using an open source library, and here is how they draw the .gif - After it has been drawn in the memory- :

Code:

---

boolean GIF::WriteFile(const char* filename,GIF_FORMAT gf)
{
        if((output_file=fopen(filename, WRITE_BINARY)) == NULL) return FALSE;

        HeaderWriteFile();
        PixelsWriteFile();
        FinishWriteFile();
        fclose(output_file);

  if(gf==GIF89a)
  {
      rename(filename,"$tmpgif$.gif");
          if(Gif87aToGif89a("$tmpgif$.gif",filename)) return FALSE;
  }

        return TRUE;
}

---

As you see, it is properly closed!

Other suggestions?

Ali

I had a different similar problem.

My guess is that you are missing a Dispose() something in either your pictureBox code or in the display of the image.

I agree. If you're using a FileStream to open a stream for C# to read the gif image you have to close it afterwards.

The nicest way of doing this is by the "using" keyword :

See here :

http://www.codeguru.com/Csharp/Cshar...cle.php/c8679/

Darwen.

Ait! Works now!

Thanks guys!

Ali