C# Deleting File "A first chance exception of type 'System.IO.IOException' occurred in mscorlib.dll"

Question

I'm trying to add a picture of part of a form to a PDF so I'm using PDFsharp, but one of the problems I have is that I can't delete the picture after I have added it to the PDF file.

This is the code I'm using:

private void button12_Click(object sender, EventArgs e)
{
    string path = @"c:\\Temp.jpeg";
    Bitmap bmp = new Bitmap(314, this.Height);
    this.DrawToBitmap(bmp, new Rectangle(Point.Empty, bmp.Size));
    bmp.Save(path, System.Drawing.Imaging.ImageFormat.Jpeg);

    GeneratePDF("test.pdf",path);
    var filestream = new System.IO.FileStream(path, System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.ReadWrite);
    filestream.Close();
    if (File.Exists(path))
    {
        File.Delete(path);
    }
}

private void GeneratePDF(string filename, string imageLoc)
{
    PdfDocument document = new PdfDocument();

    // Create an empty page or load existing
    PdfPage page = document.AddPage();

    // Get an XGraphics object for drawing
    XGraphics gfx = XGraphics.FromPdfPage(page);
    DrawImage(gfx, imageLoc, 50, 50, 250, 250);

    // Save and start View
    document.Save(filename);
    Process.Start(filename);
}

void DrawImage(XGraphics gfx, string jpegSamplePath, int x, int y, int width, int height)
{
    XImage image = XImage.FromFile(jpegSamplePath);
    gfx.DrawImage(image, x, y, width, height);
}

The FileStream is there because I was trying to make sure that it was closed and if that was the problem. This is where I got the code for writing the picture to the PDF overlay-image-onto-pdf-using-pdfsharp and this is where I got the code to make a picture of the form capture-a-form-to-image

Did I miss something obvious?
Or is there a better way to do this?

the only thing i get is "A first chance exception of type 'System.IO.IOException' occurred in mscorlib.dll" — Drago87, Mar 03 '17 at 07:48
using a `using` block would make the solution a little more elegant. Have a look at my edit — Mong Zhu, Mar 03 '17 at 10:28

Mong Zhu · Accepted Answer · 2017-03-03T08:23:10.373

If you read the details of the System.IO.IOException it tells you that

the file cannot be accessed because it is used by another process.

The process that is still using your image is this nice object:

XImage image = XImage.FromFile(jpegSamplePath);

The solution would be to dispose the image after you have drawn it to the PDF:

void DrawImage(XGraphics gfx, string jpegSamplePath, int x, int y, int width, int height)
{
    XImage image = XImage.FromFile(jpegSamplePath);
    gfx.DrawImage(image, x, y, width, height);

    image.Dispose();
}

And now the Exception vanishes into thin air....as does your file...

EDIT

A more elegant solution would be use a using block, this will make sure that Dispose() is called after you are finished with the file:

void DrawImage(XGraphics gfx, string jpegSamplePath, int x, int y, int width, int height)
{
    using (XImage image = XImage.FromFile(jpegSamplePath))
    {
        gfx.DrawImage(image, x, y, width, height);
    }
}

score 0 · Answer 2 · answered Mar 04 '17 at 08:47

To answer the second question "Or is there a better way to do this?"

Using a MemoryStream instead of a file would work around the issue. And it would improve performance. Workarounds are bad, but performance improvements are good.

The MemoryStream could be passed as a parameter. That's cleaner than having a fixed filename. And it makes no practical difference whether you pass a filename or a MemoryStream inside you program.

C# Deleting File "A first chance exception of type 'System.IO.IOException' occurred in mscorlib.dll"

2 Answers2