如何调用异步回调中的事件处理程序，以便在调用线程中运行

我正在开发一个由不同应用程序使用的VS项目/解决方案。我的工作是重构项目，并将其从使用xxxAsync方法改为使用BeginInvoke。

I am working on a VS project/solution that is used by different applications. My job is to refactor the project and change it from using xxxAsync method to using BeginInvoke.

我想出了类似于下面的代码：

I came up to something similar to the following code:

public class AsyncTestModel {
    private delegate string DoTaskDelegate();

    public static EventHandler<TaskCompletedEventArgs> OnTaskCompleted;

    public static void InvokeTask() {
        DoTaskDelegate taskDelegate = Task;
        taskDelegate.BeginInvoke(new AsyncCallback(TaskCallback), null);
    }

    private static string Task() {
        Thread.Sleep(5000);
        return "Thread Task successfully completed.";
    }

    private static void TaskCallback(IAsyncResult ar) {
        string result = ((DoTaskDelegate)((System.Runtime.Remoting.Messaging.AsyncResult)ar).AsyncDelegate).EndInvoke(ar);
        if (OnTaskCompleted != null) {
            OnTaskCompleted(null, new TaskCompletedEventArgs(result));
        }
    }
}

public class TaskCompletedEventArgs : EventArgs {
    private string _message;

    public TaskCompletedEventArgs(string message) : base() {
        _message = message;
    }

    public string Message {
        get {
            return _message;
        }
    }
}

我创建的一个新的UI项目。 UI项目包含一个按钮和一个标签控件。 UI有以下代码：

I've tested this on a new UI project I've created. The UI project contains a button and a label controls. The UI has the following code:

    private void button1_Click(object sender, EventArgs e) {
        AsyncTestModel.OnTaskCompleted += OnTaskCompleted;
        AsyncTestModel.InvokeTask();
    }

    private void OnTaskCompleted(object sender, TaskCompletedEventArgs e) {
        UpdateLabel(e.Message);
    }

    private void UpdateLabel(string message) {
        this.label1.Text = message;
    }

运行此操作后，我遇到了跨线程异常，

After running this, I've encountered the cross-thread exception saying the the control 'label1' is being accessed from other thread aside the thread that it was created.

有一种方法让我在同一个线程上调用OnTaskCompleted事件处理程序调用BeginInvoke方法？我知道我可以使用表单的InvokeRequired，并像下面这样调用窗体的BeginInvoke：

Is there a way for me to invoke the OnTaskCompleted event handler on the same thread that calls the BeginInvoke method? I know I could just use the form's InvokeRequired and call the form's BeginInvoke like the following:

    private delegate void DoUpdateLabelDelegate(string message);

    private void UpdateLabel(string message) {
        if (this.InvokeRequired) {
            IAsyncResult ar = this.BeginInvoke(new DoUpdateLabelDelegate(UpdateLabel), message);
            this.EndInvoke(ar);
            return;
        }
        this.label1.Text = message;
    }

但是上面的解决方案会要求我提出问题，开发团队处理使用我的项目/解决方案的应用程序。这些其他开发人员不应该被要求知道挂钩到事件处理程序的方法是从不同的线程运行的。

But the solution above will require me to ask and apply that solution to the other development team handling applications that uses my project/solution. Those other developers shouldn't be required to know that the methods hooked to the event handler are running from different thread.

先感谢，