c# - 事件未在表单中正确引发

Question

我有一个带有事件处理程序的主窗口，它不能正常工作。我已经制作了这个问题的简单模型。请在问题所在的代码中查看注释:

public partial class MainWindow : Window
{
    public event EventHandler Event1;

    public MainWindow()
    {
        Event1 += MainWindow_Event1;
        InitializeComponent();
    }

    void MainWindow_Event1(object sender, EventArgs e)
    {
        textBox1.Text = "wth!?";  //Not changing text box. Not showing message. If delete this line, it will work fine
        MessageBox.Show("raised");  
    }

    private void bw_DoWork(object sender, DoWorkEventArgs e)
    {
        EventHandler evt = Event1;
        while (true)
        {
            Thread.Sleep(500);
            evt(null, null);
        }
    }

    private void Button_Click_1(object sender, RoutedEventArgs e)
    {
        BackgroundWorker bw = new BackgroundWorker();
        bw.DoWork += bw_DoWork;
        bw.RunWorkerAsync();

    }

}

请解释此行为，我该如何解决？

Answer 1

问题是您从后台线程调用事件。这将不起作用，并且程序在尝试访问 TextBox 时只是挂起。但是，如果您更改此代码:

textBox1.Text = "wth!?";  //Not changing text box. Not showing message. If delete this line, it will work fine
MessageBox.Show("raised"); 

为此:

this.Dispatcher.BeginInvoke((Action)delegate()
{
    textBox1.Text = "wth!?";  //Not changing text box. Not showing message. If delete this line, it will work fine
    MessageBox.Show("raised"); 
});

它会为你工作。