为什么WinForm会被BackgroundWorker困住？

Question

嗨伙计们我试图用这个代码复制一些文件一切都很好，应用程序将复制文件，但在复制进度我无法移动我的应用程序或做任何我尝试使用线程，但它不起作用我也使用backgroundWorker但仍然没有什么是唯一的不会卡住的控件是progressBar，它的工作正常，这是我的代码：

 public Form1()
    {
        InitializeComponent();
        backgroundWorker1.Dispose();
        backgroundWorker1.DoWork += BackgroundWorker_DoWork;
        backgroundWorker1.RunWorkerCompleted += BackgroundWorker_RunWorkerCompleted;
        backgroundWorker1.ProgressChanged += BackgroundWorker_ProgressChanged;
        backgroundWorker1.WorkerReportsProgress = true;

        backgroundWorker2.DoWork += BackgroundWorker2_DoWork;
        backgroundWorker2.WorkerReportsProgress = true;
    }

    private void BackgroundWorker2_DoWork(object sender, DoWorkEventArgs e)
    {
        File.Copy(sourcePath, targetPath);
    }

    private void BackgroundWorker_DoWork(object sender, DoWorkEventArgs e)
    {
        for (int i = 0; i < fileSize; i++)
        {
            int p = (i + 1) * 100 / Convert.ToInt32(fileSize);
            backgroundWorker1.ReportProgress(p);
        }
    }

    private void BackgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {

    }

    private void BackgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
        lbProgress.Text = e.ProgressPercentage.ToString();
        progressBar1.Value = e.ProgressPercentage;
    }

    private void btnTarget_Click(object sender, EventArgs e)
    {
        folderBrowser = new FolderBrowserDialog();
        if (folderBrowser.ShowDialog() == System.Windows.Forms.DialogResult.OK)
        {
            targetPath += folderBrowser.SelectedPath + @"\" + fileName;
            lbTarget.Text = targetPath;
        }
    }

    private void btnSource_Click(object sender, EventArgs e)
    {
        op = new OpenFileDialog();
        if (op.ShowDialog() == DialogResult.OK)
        {
            sourcePath += op.FileName;
            lbSource.Text = sourcePath;
            fileInfo = new FileInfo(sourcePath);
            fileSize = fileInfo.Length / 1024;
            fileName = fileInfo.Name;
            MessageBox.Show(string.Format("File size is: {0} KB", fileSize));
        }
    }

    private void btnCopy_Click(object sender, EventArgs e)
    {
        backgroundWorker1.RunWorkerAsync();
        backgroundWorker2.RunWorkerAsync();
    }

Answer 1

对于正在紧密循环中复制的文件的每个字节，您更新进度条的速度比UI更新的速度快。你的UI线程充满了毫无意义的工作。

删除backgroundWorker1，它无论如何都没有做任何有用的事情。如果你没有办法跟踪进度（你没有使用File.Copy），只需使用没有进度的进度条（将样式设置为选框）。

Answer 2

为了测试，我创建了一个带有按钮，标签和后台工作程序的简单winform应用程序，并添加了以下相应的事件：

private void OnBackgroundWorkerDoWork(object sender, DoWorkEventArgs e)
{
    var worker = (BackgroundWorker)sender;

    for (int i = 0; i < 10; i++)
    {
        Thread.Sleep(500);
        worker.ReportProgress(i * 10);
    }
}

private void OnBackgroundWorkerProgressChanged(object sender, ProgressChangedEventArgs e)
{
    labelProgress.Text = e.ProgressPercentage.ToString();
}

private void OnBackgroundWorkerRunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
    labelProgress.Text = "Done";
}

private void OnButtonProgressClick(object sender, System.EventArgs e)
{
    backgroundWorker.RunWorkerAsync();
}

按预期工作。

Answer 3

您可以尝试将DoWork更新为：

private void BackgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
    int mainProgress = 0;
    for (int i = 0; i < fileSize; i++)
    {
        int calculatedProgress = (i + 1) * 100 / Convert.ToInt32(fileSize);
        if(calculatedProgress > mainProgress)
        {
            mainProgress = calculatedProgress;
            backgroundWorker1.ReportProgress(mainProgress);
        }
    }
}

也许你正在做这么多的更新，只是Window Thread一直只更新进度而没有时间做其他事情？