Cross.Thread违规

Question

我有一个包含事件和自定义EventArgs的类。有意义的代码：

    public void OnTickReceived(TickReceivedEventArgs e)
    {
        EventHandler<TickReceivedEventArgs> handler = TickReceived;
        if (handler != null)
            handler(this, e);
    }

    public event EventHandler<TickReceivedEventArgs> TickReceived = delegate { };

并使用UI Windows窗体中的类来订阅事件，如下所示

    private void button4_Click(object sender, EventArgs e)
    {
        bool esito;
        t = new T3OpenStockReader();
        esito = t.Connect();
        textBox1.Text += "Connection: " + esito.ToString() + "\r\n";
        Application.DoEvents();
        if (esito)
        {
            esito = t.Subscribe("MI.EQCON.2552");
            textBox1.Text += "Subscription: " + esito.ToString() + "\r\n";
            Application.DoEvents();
        }
        if (esito)
        {
            t.Start();
            t.TickReceived += NewTick_Event;
            System.Diagnostics.Debug.Print("Reading started...");
        }

    }

    private void NewTick_Event(object sender, TickReceivedEventArgs e)
    {
        textBox1.Text += e.tick.DT + " " + e.tick.Price + " " + e.tick.Volume + "\r\n"; 
    }

我收到一个InvalidOperationException - cross.thread操作。我做错了什么？

Answer 1

I收到InvalidOperationException - cross.thread操作。我的错误在哪里？

假设T3OpenStockReader在它自己的线程上引发事件--但您正在尝试修改事件处理程序中的UI……这意味着你在错误的线程中做了。您可能应该将事件处理程序更改为类似以下内容：

private void NewTick_Event(object sender, TickReceivedEventArgs e)
{
    Action action = () => textBox1.Text += e.tick.DT + " " + e.tick.Price 
                                           + " " + e.tick.Volume + "\r\n"; 
    textBox1.BeginInvoke(action);
}

我还建议你摆脱你的Application.DoEvents()调用-它们是试图在UI线程中做太多事情的症状。

Answer 2

我假设您正在尝试更新非UI线程上的UI组件，即NewTick_Event。您需要强制更新回到UI线程上，例如

private void NewTick_Event(object sender, TickReceivedEventArgs e)
{
    textBox1.Invoke(new Action(() => textBox1.Text += e.tick.DT + " " + e.tick.Price + " " + e.tick.Volume + "\r\n")); 
}

Answer 3

从另一个线程调用NewTick_Event，并且必须在UI线程上调用对控件的更改(例如，使用BeginInvoke方法)。

private void NewTick_Event(object sender, TickReceivedEventArgs e)
{
   this.BeginInvoke( (Action) () =>
   {
      textBox1.Text += e.tick.DT + " " + e.tick.Price + " " + e.tick.Volume + "\r\n"; 
   });
}