c# - 从后台工作人员登录MyLogger时发生跨线程InvalidOperationException

Question

我创建了一个事件驱动的记录器，从另一个线程调用时似乎出现了问题。如何使它线程安全？

这是LoggerClass:

public static class MyLogger
{
    private static List<string> log = new List<string>();
    public static event EventHandler LogAdded;
    private static string indent = "";

    public static void Log(string message)
    {
        log.Add(indent + message);
        if (LogAdded != null)
            LogAdded(null, EventArgs.Empty);
    }
}

在表单类中，我通过以下两种方式启动它:

public frm_main()
{
    InitializeComponent();
    MyLogger.LogAdded += new EventHandler(MyLogger_LogAdded);
}

这是发生崩溃的事件进度:

private void MyLogger_LogAdded(object sender, EventArgs e)
{
    int length = rtb_logger.TextLength;  // at end of text
    string prefix = string.Format("{0:d3}: ", ++logindex);
    string ToAppend = prefix + MyLogger.GetLastLog();
    rtb_logger.AppendText(ToAppend);
    if (ToAppend.Contains("Alert -"))
    {
        rtb_logger.SelectionStart = length;
        rtb_logger.SelectionLength = ToAppend.Length;
        rtb_logger.SelectionColor = Color.Red;
    }
    rtb_logger.AppendText(Environment.NewLine);
    rtb_logger.SelectionStart = rtb_logger.TextLength;
    rtb_logger.ScrollToCaret();
    EnableControls();
}

在背景工作人员的以下调用中，崩溃发生在上面第一行注释为“文本末尾”的行:

MyLogger.Log("Sending cmd: \"" + strCmdText + "\" to CMD.exe.");

如何使MyLogger类具有线程安全性？

编辑:使用SeeSharp解决方案，代码更改为:

private void MyLogger_LogAdded(object sender, EventArgs e)
{
    if (rtb_logger.InvokeRequired)
    {
        rtb_logger.BeginInvoke(new Action(delegate {
            MyLogger_LogAdded(sender, e);
        }));
        return;
    }
    int length = rtb_logger.TextLength;  // at end of text
    string prefix = string.Format("{0:d3}: ", ++logindex);
    string ToAppend = prefix + MyLogger.GetLastLog();
    rtb_logger.AppendText(ToAppend);
    if (ToAppend.Contains("Alert -"))
    {
        rtb_logger.SelectionStart = length;
        rtb_logger.SelectionLength = ToAppend.Length;
        rtb_logger.SelectionColor = Color.Red;
    }
    rtb_logger.AppendText(Environment.NewLine);
    rtb_logger.SelectionStart = rtb_logger.TextLength;
    rtb_logger.ScrollToCaret();
    EnableControls();
}

Answer 1

您必须在UI线程中调用MyLogger_LogAdded的主体。
调用rtb_logger的方法或属性时，请尝试使用Dispatcher.BeginInvoke()。

参见C#: Thread safe richtextbox event logging method?