Error Cannot Access File because it is being used by another process : The Official Microsoft ASP.NET Forums

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glenng910

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82 Points

Error Cannot Access File because it is being used by another process

Feb 10, 2010 03:57 PM|LINK

I googled this error but cannot find anything that relates to my case. I am writing a photo gallery as an exercise, and I am running into this error. I have a Gallery class that includes a List<of Photo objects) collection. My application lets me write the gallery (just text - photo name, path, etc) to an XML file and read it back. The problem occurs when I read it back twice in succession. Here is the method that does this:

 private void btnLoad_Click(object sender, EventArgs e)

        {
            string fname = "";


            if (lbGallery.SelectedIndex >= 0)
            {
               

                flowLayoutPanel1.Controls.Clear();
                fname = (string)lbGallery.SelectedItem;
                Gallery g = new Gallery(fname, GalleryPath + "\\");
                txtGalleryName.Text = fname;
                // Creates the ClubPix collection from xml disk file
                g.LoadGallery();


                // loop through clubpix list and create thumbnails
                foreach (var itm in g.PicCollection)
                {
                    if (File.Exists(itm.FsPath + ThumbFolder +itm.PicName))
                    {
                        File.Delete(itm.FsPath + ThumbFolder + itm.PicName);
                    }
                    CreateThumb(itm.PicName, itm.FsPath, itm.FsPath+ThumbFolder);
     

                }
                DisplayThumbNails(g.PicCollection);
            }

I added the File.exists/File.Delete code to isolate the error. When I press the load button, the xml file is read and the g.PicCollection is populated. The thumbnails are displayed. If I then just press the Load button again, I get the error below saying that the file cannot be deleted because it is being used by another process. The thumbnails are loaded into pictureboxes on a flowpanel, I clear those in the code above. So the file is apparantly open, but I don't how? This is on a development machine, so no other users involved.

ERROR The process cannot access the file 'C:\Users\Public\Pictures\Sample Pictures\thumbs\Chrysanthemum.jpg' because it is being used by another process.

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Kumar Reddi

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14340 Points

2619 Posts

Re: Error Cannot Access File because it is being used by another process

Feb 10, 2010 06:39 PM|LINK

glenng910

ERROR The process cannot access the file 'C:\Users\Public\Pictures\Sample Pictures\thumbs\Chrysanthemum.jpg' because it is being used by another process.

The simplest way to fix these kind of issues is to see what process is holding this file's handle.

Start by downloading ProcExp from Microsoft. Heres the url

http://technet.microsoft.com/en-us/sysinternals/bb896653.aspx

Now, run this tool and click on the Find from the top menu. In the dailog box, enter your file name(complete or partial) and it will list all the processes that are holding a reference to this file

Kumar Reddi

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glenng910

Member

82 Points

97 Posts

Re: Error Cannot Access File because it is being used by another process

Feb 10, 2010 07:38 PM|LINK

Thank you. That is a useful tool. In this case though, it shows that only my program has the file open. When I reload, even though I have cleared all the controls, apparantly the file remains open. I am not sure how to close it. It is an image in a picturebox and the picturebox is gone.

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Kumar Reddi

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14340 Points

2619 Posts

Re: Error Cannot Access File because it is being used by another process

Feb 10, 2010 07:50 PM|LINK

Show us the CreateThumb method code. It seems like you are not closing the File handle that you open to create the file

Kumar Reddi

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glenng910

Member

82 Points

97 Posts

Re: Error Cannot Access File because it is being used by another process

Feb 10, 2010 08:02 PM|LINK

Found this code here in the forums.

private void CreateThumb(string FileName, string path, string thPath)
        // http://forums.asp.net/p/1206493/2113692.aspx#2113692
        {


            Bitmap bm = (Bitmap)Image.FromFile(path+"//"+FileName);
            int shtWidth = 0;
            int shtHeight = 0;


            shtHeight = bm.Height / ThumbScale;
            shtWidth = bm.Width / ThumbScale;
            Bitmap resized = new Bitmap(shtWidth, shtHeight);
            Graphics g = Graphics.FromImage(resized);
            g.InterpolationMode = InterpolationMode.HighQualityBicubic;
            g.DrawImage(bm, new Rectangle(0, 0, resized.Width, resized.Height), 0, 0, bm.Width, bm.Height, GraphicsUnit.Pixel);
            g.Dispose();
          



            resized.Save(thPath + FileName, ImageFormat.Jpeg);
            txtError.Text = "Thumbs Created";
        }

Edited by glenng910 on Feb 10, 2010 08:03 PM

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Kumar Reddi

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14340 Points

2619 Posts

Re: Error Cannot Access File because it is being used by another process

Feb 10, 2010 08:13 PM|LINK

You need to dispose the Bitmap you are creating.

add the following code at the end, before the close of the braces

bm.Dispose();

Kumar Reddi

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glenng910

Member

82 Points

97 Posts

Re: Error Cannot Access File because it is being used by another process

Feb 10, 2010 08:30 PM|LINK

I added that and resized.Dispose() also. Didn't help. I am still getting the same error.

private void CreateThumb(string FileName, string path, string thPath)
        // http://forums.asp.net/p/1206493/2113692.aspx#2113692
        {


            Bitmap bm = (Bitmap)Image.FromFile(path+"//"+FileName);
            int shtWidth = 0;
            int shtHeight = 0;


            shtHeight = bm.Height / ThumbScale;
            shtWidth = bm.Width / ThumbScale;
            Bitmap resized = new Bitmap(shtWidth, shtHeight);
            Graphics g = Graphics.FromImage(resized);
            g.InterpolationMode = InterpolationMode.HighQualityBicubic;
            g.DrawImage(bm, new Rectangle(0, 0, resized.Width, resized.Height), 0, 0, bm.Width, bm.Height, GraphicsUnit.Pixel);
            g.Dispose();
          



            resized.Save(thPath + FileName, ImageFormat.Jpeg);
            txtError.Text = "Thumbs Created";
            resized.Dispose();
            bm.Dispose();
        }