如何使用后台工作者？

Question

我知道它有3种方法。在我的程序中，我有一个发送消息的方法。通常会很晚，并且程序有时根本不发送消息来响应按钮按下。有时，它比我预期晚了 5 秒，程序就会冻结。我想使用 BackgroundWorker 按预期发送消息并允许程序始终正常运行。我有在按钮处理程序中发送消息的代码。现在我应该把这个等效的代码放在哪里？我希望所有这些仍然可以通过按下按钮来处理。

这是合适的处理程序吗？

backgroundWorker1.RunWorkerAsync();

并在：

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e) {}

我要将我的代码放入按钮处理程序中？ 之前的内容是：

carga.progressBar1.Minimum = 0;
carga.progressBar1.Maximum = 100;

Carga 是我的另一种形式，ProgressBar 就在其中。在这种情况下如何使用BackgroundWorker？

Answer 1

您只能从 ProgressChanged 或 RunWorkerCompleted 事件处理程序更新进度栏，因为它们与 UI 线程同步。

基本思想是。 Thread.Sleep 只是在这里模拟一些工作。将其替换为您真实的路由调用。

public Form1()
{
    InitializeComponent();

    backgroundWorker1.DoWork += backgroundWorker1_DoWork;
    backgroundWorker1.ProgressChanged += backgroundWorker1_ProgressChanged;
    backgroundWorker1.WorkerReportsProgress = true;
}

private void button1_Click(object sender, EventArgs e)
{
    backgroundWorker1.RunWorkerAsync();
}

private void backgroundWorker1_DoWork(object sender, System.ComponentModel.DoWorkEventArgs e)
{
    for (int i = 0; i < 100; i++)
    {
        Thread.Sleep(1000);
        backgroundWorker1.ReportProgress(i);
    }
}

private void backgroundWorker1_ProgressChanged(object sender, System.ComponentModel.ProgressChangedEventArgs e)
{
    progressBar1.Value = e.ProgressPercentage;
}

Answer 2

我知道这有点旧了，但如果另一个初学者正在经历这个，我将分享一些涵盖更多基本操作的代码，这是另一个示例，其中还包括取消过程和报告的选项向用户显示进程的状态。我将在上面的解决方案中添加 Alex Aza 给出的代码

public Form1()
{
    InitializeComponent();

    backgroundWorker1.DoWork += backgroundWorker1_DoWork;
    backgroundWorker1.ProgressChanged += backgroundWorker1_ProgressChanged;
    backgroundWorker1.RunWorkerCompleted += backgroundWorker1_RunWorkerCompleted;  //Tell the user how the process went
    backgroundWorker1.WorkerReportsProgress = true;
    backgroundWorker1.WorkerSupportsCancellation = true; //Allow for the process to be cancelled
}

//Start Process
private void button1_Click(object sender, EventArgs e)
{
    backgroundWorker1.RunWorkerAsync();
}

//Cancel Process
private void button2_Click(object sender, EventArgs e)
{
    //Check if background worker is doing anything and send a cancellation if it is
    if (backgroundWorker1.IsBusy)
    {
        backgroundWorker1.CancelAsync();
    }

}

private void backgroundWorker1_DoWork(object sender, System.ComponentModel.DoWorkEventArgs e)
{
    for (int i = 0; i < 100; i++)
    {
        Thread.Sleep(1000);
        backgroundWorker1.ReportProgress(i);

        //Check if there is a request to cancel the process
        if (backgroundWorker1.CancellationPending)
        {
            e.Cancel = true;
            backgroundWorker1.ReportProgress(0);
            return;
        }
    }
    //If the process exits the loop, ensure that progress is set to 100%
    //Remember in the loop we set i < 100 so in theory the process will complete at 99%
    backgroundWorker1.ReportProgress(100);
}

private void backgroundWorker1_ProgressChanged(object sender, System.ComponentModel.ProgressChangedEventArgs e)
{
    progressBar1.Value = e.ProgressPercentage;
}

private void backgroundWorker1_RunWorkerCompleted(object sender, System.ComponentModel.RunWorkerCompletedEventArgs e)
{
    if (e.Cancelled)
    {
         lblStatus.Text = "Process was cancelled";
    }
    else if (e.Error != null)
    {
         lblStatus.Text = "There was an error running the process. The thread aborted";
    }
    else
    {
       lblStatus.Text = "Process was completed";
    }
}

Answer 3

试试这个：

    private BackgroundWorker worker;

    public MainWindow()
    {
        InitializeComponent();
        InitializeBackgroundWorker();
    }

    private void InitializeBackgroundWorker()
    {
        worker = new BackgroundWorker
        {
            WorkerReportsProgress = true,
            WorkerSupportsCancellation = true
        };

        worker.DoWork += Worker_DoWork;
        worker.ProgressChanged += Worker_ProgressChanged;
        worker.RunWorkerCompleted += Worker_RunWorkerCompleted;
    }

    private void Worker_DoWork(object sender, DoWorkEventArgs e)
    {
        // Simulate a time-consuming operation
        for (int i = 1; i <= 100; i++)
        {
            if (worker.CancellationPending)
            {
                e.Cancel = true;
                return;
            }

            // Do the actual work here
            Thread.Sleep(100);

            // Report progress to UI thread
            worker.ReportProgress(i);
        }
    }

    private void Worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
        progressBar.Value = e.ProgressPercentage;
    }

    private void Worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        if (e.Cancelled)
        {
            MessageBox.Show("Operation was canceled.", "Canceled", MessageBoxButton.OK, MessageBoxImage.Information);
        }
        else if (e.Error != null)
        {
            MessageBox.Show("Error occurred: " + e.Error.Message, "Error", MessageBoxButton.OK, MessageBoxImage.Error);
        }
        else
        {
            MessageBox.Show("Operation completed successfully.", "Completed", MessageBoxButton.OK, MessageBoxImage.Information);
        }
    }

    private void StartButton_Click(object sender, RoutedEventArgs e)
    {
        if (!worker.IsBusy)
        {
            // Start the background worker
            worker.RunWorkerAsync();
        }
    }

    private void Cancel_Click(object sender, RoutedEventArgs e)
    {
    worker.CancelAsync();

    }