I have this problem when I drag to select region of the image in the picturebox more than two times and run the scanning. This is an OCR system.

region OCR(Tab4_Component)

    //When user is selecting, RegionSelect = true
    private bool RegionSelect = false;
    private int x0, x1, y0, y1;
    private Bitmap bmpImage;

    private void loadImageBT_Click(object sender, EventArgs e)
    {
        try
        {
            OpenFileDialog open = new OpenFileDialog();
            open.InitialDirectory = @"C:\Users\Shen\Desktop";

            open.Filter = "Image Files(*.jpg; *.jpeg)|*.jpg; *.jpeg";

            if (open.ShowDialog() == DialogResult.OK)
            {
                singleFileInfo = new FileInfo(open.FileName);
                string dirName = System.IO.Path.GetDirectoryName(open.FileName);
                loadTB.Text = open.FileName;
                pictureBox1.Image = new Bitmap(open.FileName);
                bmpImage = new Bitmap(pictureBox1.Image);
            }
            
        }
        catch (Exception)
        {
            throw new ApplicationException("Failed loading image");
        }
    }

    //User image selection Start Point
    private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
    {
        RegionSelect = true;

        //Save the start point.
        x0 = e.X;
        y0 = e.Y;
    }

    //User select image progress
    private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
    {
        //Do nothing it we're not selecting an area.
        if (!RegionSelect) return;

        //Save the new point.
        x1 = e.X;
        y1 = e.Y;

        //Make a Bitmap to display the selection rectangle.
        Bitmap bm = new Bitmap(bmpImage);
        

        //Draw the rectangle in the image.
        using (Graphics g = Graphics.FromImage(bm))
        {
            g.DrawRectangle(Pens.Red, Math.Min(x0, x1), Math.Min(y0, y1), Math.Abs(x1 - x0), Math.Abs(y1 - y0));
        }

        //Temporary display the image.
        pictureBox1.Image = bm;
    }

    //Image Selection End Point
    private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
    {
        // Do nothing it we're not selecting an area.
        if (!RegionSelect) return;
        RegionSelect = false;

        //Display the original image.
        pictureBox1.Image = bmpImage;

        // Copy the selected part of the image.
        int wid = Math.Abs(x0 - x1);
        int hgt = Math.Abs(y0 - y1);
        if ((wid < 1) || (hgt < 1)) return;

        Bitmap area = new Bitmap(wid, hgt);
        using (Graphics g = Graphics.FromImage(area))
        {
            Rectangle source_rectangle = new Rectangle(Math.Min(x0, x1), Math.Min(y0, y1), wid, hgt);
            Rectangle dest_rectangle = new Rectangle(0, 0, wid, hgt);
            g.DrawImage(bmpImage, dest_rectangle, source_rectangle, GraphicsUnit.Pixel);
        }

        // Display the result.
        pictureBox3.Image = area;
        area.Save(@"C:\Users\Shen\Desktop\LenzOCR\TempFolder\tempPic.jpg");
        singleFileInfo = new FileInfo("C:\\Users\\Shen\\Desktop\\LenzOCR\\TempFolder\\tempPic.jpg");
    }


           private void ScanBT_Click(object sender, EventArgs e)
    {
        var folder = @"C:\Users\Shen\Desktop\LenzOCR\LenzOCR\WindowsFormsApplication1\ImageFile";

        DirectoryInfo directoryInfo;
        FileInfo[] files;
        directoryInfo = new DirectoryInfo(folder);
        files = directoryInfo.GetFiles("*.jpg", SearchOption.AllDirectories);

        var processImagesDelegate = new ProcessImagesDelegate(ProcessImages2);
        processImagesDelegate.BeginInvoke(files, null, null);     

        //BackgroundWorker bw = new BackgroundWorker();
        //bw.DoWork += new DoWorkEventHandler(backgroundWorker1_DoWork);
        //bw.RunWorkerAsync(bw);
        //bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(backgroundWorker1_RunWorkerCompleted);
    }
    
    private void ProcessImages2(FileInfo[] files)
    {
        var comparableImages = new List<ComparableImage>();

        var index = 0x0;

        foreach (var file in files)
        {
            if (exit)
            {
                return;
            }

            var comparableImage = new ComparableImage(file);
            comparableImages.Add(comparableImage);
            index++;
        }

        index = 0;

        similarityImagesSorted = new List<SimilarityImages>();
        var fileImage = new ComparableImage(singleFileInfo);

        for (var i = 0; i < comparableImages.Count; i++)
        {
            if (exit)
                return;

            var destination = comparableImages[i];
            var similarity = fileImage.CalculateSimilarity(destination);
            var sim = new SimilarityImages(fileImage, destination, similarity);
            similarityImagesSorted.Add(sim);
            index++;
        }

        similarityImagesSorted.Sort();
        similarityImagesSorted.Reverse();
        similarityImages = new BindingList<SimilarityImages>(similarityImag开发者_如何转开发esSorted);

        var buttons =
            new List<Button>
                {
                    ScanBT
                };

        if (similarityImages[0].Similarity > 70)
        {
            con = new System.Data.SqlClient.SqlConnection();
            con.ConnectionString = "Data Source=SHEN-PC\\SQLEXPRESS;Initial Catalog=CharacterImage;Integrated Security=True";
            con.Open();

            String getFile = "SELECT ImageName, Character FROM CharacterImage WHERE ImageName='" + similarityImages[0].Destination.ToString() + "'";
            SqlCommand cmd2 = new SqlCommand(getFile, con);
            SqlDataReader rd2 = cmd2.ExecuteReader();

            while (rd2.Read())
            {
                for (int i = 0; i < 1; i++)
                {
                    string getText = rd2["Character"].ToString();
                    Action showText = () => ocrTB.AppendText(getText);
                    ocrTB.Invoke(showText);
                }
            }
            con.Close();
        }
        else
        {
            MessageBox.Show("No character found!", "Error!", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }

    }
    #endregion

i understand the reason it occur is that the image has been duplicated. But I have no idea how to solve it.

First off this looks like a dublicate of this topic: c# Bitmap.Save A generic error occurred in GDI+ windows application

You also authored that question. From what I can tell it's the same question regarding the same code.

You mention this happens the second time you select an area, and both time you save the image to the same path. You also say the errors occurs when saving.

I think that would be a very strong indication of a permission error. Have you tried saving to a new file name every time as a test?

If it's a permission error then you simply need to dispose of any resources that have taken a lock on that file.

There are plenty of examples of this out there: http://www.kerrywong.com/2007/11/15/understanding-a-generic-error-occurred-in-gdi-error/

    public void Method1()
    {
        Image img = Image.FromFile(fileName);
        Bitmap bmp = img as Bitmap;
        Graphics g = Graphics.FromImage(bmp);
        Bitmap bmpNew = new Bitmap(bmp);
        g.DrawImage(bmpNew, new Point(0, 0));
        g.Dispose();
        bmp.Dispose();
        img.Dispose();

        //code to manipulate bmpNew goes here.

        bmpNew.Save(fileName);
    }

There could however be other issues. If you get the image from a stream, this stream needs to remain open until you're done with the image. (When you dispose of the image you'll automatically dispose of the stream.) I can't see anything like that in the code you've posted though.

If you are using a 3rd party library for the OCR part, it could also have taken a lock on the resource.

A good place to read about this would be here: http://support.microsoft.com/?id=814675

However from all you've said it simply sounds like there's a lock on the file you try to save to. So as mentioned above I would start off by simply trying to give the file a new name each time. If it doesn't work then you can start exploring other possibilities.

Quick and dirty example:

area.Save(@"C:\Users\Shen\Desktop\LenzOCR\TempFolder\tempPic-" + Guid.NewGuid().ToString() + @".jpg");

You should try this before dismissing a permission issue.