Question

我使用后台工作程序设置ProgressBar以显示下载文件时的进度。但BackgroundWorker的RunWorkerAsync（）方法不会触发Do_Work事件。

/ ********** Window_Load *********** /

        BackgroundWorker backgroundWorker1;
    private void MainWindow_Load(object sender, RoutedEventArgs e)
    {
    backgroundWorker1=new BackgroundWorker();
    backgroundWorker1.WorkerReportsProgress=true;
    backgroundWorker1.DoWork +=new DoWorkEventHandler(backgroundWorker1_DoWork);
    backgroundWorker1.ProgressChanged +=new ProgressChangedEventHandler(backgroundWorker1_ProgressChanged);
    backgroundWorker1.RunWorkerCompleted +=new RunWorkerCompletedEventHandler(backgroundWorker1_RunWorkerCompleted);
    }

/ ****** ******* Button_Click /

void Button_Click(object sender, RoutedEventArgs e)
    {
            backgroundWorker1.RunWorkerAsync();
    }

/ **** *********活动/

        private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
        ProgressBar1.Value = e.ProgressPercentage;
    }
    private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        MessageBox.Show("File download complete");
    }


private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
    {
    //Code to download a file and setting progressbar time. 
    }

我是WPF的新手。任何帮助表示赞赏。

Answer 1

您的代码看起来很好，但代码没有变化..想要了解以下内容

检查您的点击事件是否有效...按钮点击正在运行
在点击事件中设置断点并在点击事件正常工作时进行调试

我建议你可以查看一下这篇文章: Multi-threading with the BackgroundWorker，这与你正在做同样的事情。你可能会找不到的东西。

Answer 2

我设置了一个示例项目并完全使用了您的代码，并且没有任何编程错误，它在我身边完美运行。

确保您订阅了点击事件的按钮，这似乎没有被解雇

<Button Content="Button" HorizontalAlignment="Left" Margin="153,42,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click"/>

Answer 3

试试这个例子，

<Button Content="Button" HorizontalAlignment="Left" Margin="165,58,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click"/>

 private BackgroundWorker _backgroundWorker;
        public MainWindow()
        {
            InitializeComponent();
            _backgroundWorker = new BackgroundWorker();
            _backgroundWorker.DoWork += new DoWorkEventHandler(backgroundWorker_DoWork);
            _backgroundWorker.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker_ProgressChanged);
            _backgroundWorker.RunWorkerCompleted += backgroundWorker_RunWorkerCompleted;
            _backgroundWorker.WorkerReportsProgress = true;
            DataContext = this;


        }

        private void backgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            var eee = e.Result;
        }

        private void backgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            var progrss = e.ProgressPercentage;
        }

        private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
        {
            int p=10;
            for (int index = 0; index < p; index++)
            {
                object param = "something";
                Thread.Sleep(100);
                _backgroundWorker.ReportProgress(p, param);
                Thread.Sleep(1000);
                if (index == 10)
                {
                    break;
                } 
            } 

        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            _backgroundWorker.RunWorkerAsync(); 
        }

BackgroundWorker的RunWorkerAsync（）方法不会触发Do_Work事件

3 个答案: