如何使用BackgroundWorker与自定义进度对话框(窗体与ProgressBar)

本文关键字：窗体 ProgressBar 对话框 何使用 BackgroundWorker 自定义 | 更新日期: 2023-09-27 18:12:38

我有一个加载文件的方法。有时它需要花费很多时间，所以我想向用户展示一个进度条窗口，通过它他可以最小化整个应用程序或取消进度。

我读了一堆关于后台工作人员和进度条的教程，但这些都没有涵盖的情况下，当进度条是在一些其他形式。我不知道什么时候我应该打开新的表单，以及如何访问那里的进度条。

到目前为止，我已经试过了:

MainForm: 

private void addFolderToolStripMenuItem_Click(object sender, EventArgs e)
{
    ctlFolderSelectDialog dlg = new ctlFolderSelectDialog();
    if (dlg.ShowDialog() == DialogResult.OK)
    {
        BackgroundWorker.RunWorkerAsync(dlg); // to pass some variables from ctlFolderSelectDialog
    }
}
private void BackgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
    Form_Dialogs.ProgressDialog progressDialog = new Form_Dialogs.ProgressDialog();
    progressDialog.ShowDialog(); // open the progress dialog window
    myClass.loadFiles((ctlFolderSelectDialog)e.Argument); // THE WORK
    progressDialog.Close(); // close the progress window - in here?
}

myClass: 

public void loadFiles(ctlFolderSelectDialog dlg)
{
    ...
    files.Count() // somehow report this preliminary number of files to ProgressBar window - to set ProgressBar1.Maximum value
    ...
    foreach (file in files)
    {
        loadFile();
        ... // here I should somehow udpate the progressBar on the other window - performStep()
    }
}

ProgressDialog: 

private void ProgressDialog_Load(object sender, EventArgs e)
{
    progressBar1.Value = 0;
    progressBar1.Maximum = 100; // how to get this value from myClass function? Pass in ProgressDialog contructor?
    progressBar1.Step = 1;
}
public void UpdateProgress(int progress)
{
    progressBar1.PerformStep();
}

如何使用BackgroundWorker与自定义进度对话框(窗体与ProgressBar)

BackgroundWorker支持通过ProgressChanged事件进行进度更新。

在loadFiles()方法中需要计算%的进度，在foreach循环中调用backgroundWorker.ReportProgress(percentage)。这将引发ProgressChanged事件，您可以从中获得事件参数e.ProgressPercentage。[你需要在loadFiles()方法中引用BackgroundWorker]

在ProgressDialog表单中，您需要注册此事件。您可以在构造函数中传递BackgroundWorker，例如:

public void ProgressDialog(BackgroundWorker worker)
{
   worker.ProgressChanged += ProgressDialog_ProgressChanged;
}
private void ProgressDialog_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
   UpdateProgressBar(e.ProgressPercentage);
}

和主要形式:

private void addFolderToolStripMenuItem_Click(object sender, EventArgs e)
{
    ctlFolderSelectDialog dlg = new ctlFolderSelectDialog();
    if (dlg.ShowDialog() == DialogResult.OK)
    {
        BackgroundWorker.RunWorkerAsync(dlg); // to pass some variables fromctlFolderSelectDialog
        Form_Dialogs.ProgressDialog progressDialog = 
           new Form_Dialogs.ProgressDialog(BackgroundWorker); // Pass the BackgroundWorker instance
        progressDialog.ShowDialog(); // open the progress dialog window
        // No need to explicitly close it. A dialog form is destroyed when closed by the user.
    }
}
private void BackgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
    myClass.loadFiles((ctlFolderSelectDialog)e.Argument); // THE WORK
}
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