c# – 删除另一个进程正在使用的图像教程

我正在用C#编写一个winform应用程序来打开一个图像并在其上面叠加另一个图像.

底部图像是.jpg,顶部图像是.svg转换的.bmp. .jpg和.svg是我想要保留在文件夹中的唯一内容. .bmp作为临时工作.

我使用以下代码覆盖图像.但我很难删除临时.bmp,因为它被另一个进程使用.我认为这个组合代码仍然可以访问最后一个.bmp文件.

有人可以帮我吗？谢谢.

    private void buttonSearch_Click(object sender, EventArgs e)
    {
        FailInfo.Text = "";

        deletebmp(strFolderPath); 

        ...

        // Check if the specified front image exists. Yes, show the file name and convert SVG to BMP. No, show the error msg.
        if (File.Exists(strFilePathF))
        {
            labelFront.Text = strFileNameF;
            var svgConvert = SvgDocument.Open(svgFilePathF);
            svgConvert.Draw().Save(bmpFilePathF);
            pictureBoxFront.Image = Image.FromFile(strFilePathF);
        }
        else
        {
            labelFront.Text = "Couldn't find the file!";
            pictureBoxFront.Image = null;
        }

        // Check if the specified back image exists. Yes, show the file name and convert SVG to BMP. No, show the error msg.   
        if (File.Exists(strFilePathBF))
        {
            labelBack.Text = strFileNameBF;
            strFilePathB = strFilePathBF;
            pictureBoxBack.Image = Image.FromFile(strFilePathB);
            labelResult.Text = "FAIL";
            labelResult.BackColor = Color.FromArgb(255, 0, 0);
            var svgConvert = SvgDocument.Open(svgFilePathBF);
            bmpFilePathB = strFolderPath + strFileNameBF + ".bmp";
            svgConvert.Draw().Save(bmpFilePathB);
            svgFilePathB = svgFilePathBF;
            inspectionres(svgFilePathB);
            labelreason.Visible = true;
        }
        else if (File.Exists(strFilePathBP))
        {
            labelBack.Text = strFileNameBP;
            strFilePathB = strFilePathBP;
            pictureBoxBack.Image = Image.FromFile(strFilePathB);
            labelResult.Text = "PASS";
            labelResult.BackColor = Color.FromArgb(0, 255, 0);
            var svgConvert = SvgDocument.Open(svgFilePathBP);
            bmpFilePathB = strFolderPath + strFileNameBP + ".bmp";
            svgConvert.Draw().Save(bmpFilePathB);
            svgFilePathB = svgFilePathBP;
            inspectionres(svgFilePathB);
            labelreason.Visible = false;
        }
        else
        {
            labelBack.Text = "Couldn't find the file!";
            pictureBoxBack.Image = null;
            labelResult.Text = "ERROR";
            labelResult.BackColor = Color.FromArgb(0, 255, 255);
            labelreason.Visible = false;
        }
    }

    //
    // Overlay the SVG file on top of the JPEG file
    //
    private Bitmap Combine(string jpegFile, string bmpFile)
    {        
        Image image1 = Image.FromFile(jpegFile);
        Image image2 = Image.FromFile(bmpFile);
        Bitmap temp = new Bitmap(image1.Width, image1.Height);

        using (Graphics g = Graphics.FromImage(temp))
        {
            g.DrawImageUnscaled(image1, 0, 0);
            g.DrawImageUnscaled(image2, 0, 0);
        }

        return temp;
    }

    //
    // Show the overlaid graphic in the picturebox
    //
    private void checkBoxOverlay_CheckedChanged(object sender, EventArgs e)
    {
        try
        {
            if (FindFront)
                if (checkBoxOverlay.Checked)
                    pictureBoxFront.Image = Combine(strFilePathF, bmpFilePathF);
                else
                    pictureBoxFront.Image = Image.FromFile(strFilePathF);
            else
                pictureBoxFront.Image = null;

            if (FindBack)
                if (checkBoxOverlay.Checked)
                    pictureBoxBack.Image = Combine(strFilePathB, bmpFilePathB);
                else
                    pictureBoxBack.Image = Image.FromFile(strFilePathB);
            else
                pictureBoxBack.Image = null;
        }
        catch (Exception ex)
        {
            MessageBox.Show("Error loading image" + ex.Message);
        }
    }

    //
    // Option of changing the image folder
    //
    private void buttonPath_Click(object sender, EventArgs e)
    {
        FolderBrowserDialog FolderBrowserDialog1 = new FolderBrowserDialog();
        if (FolderBrowserDialog1.ShowDialog() == DialogResult.OK)
        {
            strFolderPath = FolderBrowserDialog1.SelectedPath + "\\";
        }
    }

    //
    // Pull the inspection result info from the SVG file
    //
    private void inspectionres(string filename)
    {
        XDocument document = XDocument.Load(filename);
        XElement svg_Element = document.Root;
        string sb = null;

        var faillist = (from svg_path in svg_Element.Descendants("{http://www.w3.org/2000/svg}text") select svg_path).ToList();

        foreach (var item in faillist)
        {
            sb += item.ToString();
        }
    }

    //
    // Delete all the .bmp files generated from .svg files
    //
    private void deletebmp(string path)
    {
        // Unload the images from the picturebox if applicable
        pictureBoxFront.Image = null;
        pictureBoxBack.Image = null;

        string[] files = Directory.GetFiles(path, "*.bmp");
        for (int i = 0; i < files.Length; i ++ )
            File.Delete(files[i]);
    }
}

解决方法:

Image实现了IDisposable,因此简单地将pictureBox.Image属性设置为null将不会释放资源(在您的情况下,文件). Combine方法也会使图像保持打开状态.在尝试删除文件之前,您必须调用Dispose：

Image image1 = Image.FromFile(path1);
File.Delete(path1);  // error - file is locked 

Image image2 = Image.FromFile(path2);
image2.Dispose();
File.Delete(path2);  // works

另一种方法(我假设你在这里使用WinForms,在WPF中它有点不同)是手动加载文件中的位图(使用FromStream).然后,您可以立即关闭流并删除该文件：

Image image;
using (Stream stream = File.OpenRead(path))
{
    image = System.Drawing.Image.FromStream(stream);
}
pictureBox.Image = image;
File.Delete("e:\\temp\\copy1.png");  //works