c# - 在单独的线程中调用方法

Question

我需要在单独的线程中调用类方法。该方法有一个参数和一个返回值。

详情

我有一个带有两个文本框的表单。用户将值放入第一个 TextBox 并在第二个 TextBox 中获取结果:

 private void tbWord_TextChanged(object sender, TextChangedEventArgs e)
 {
     tbResponce.Text = Wiki.DoWork(tbWord.Text);
 }

Wiki 类必须使用 Wikipedia API:

public class Wiki
{
    private class State
    {
        public EventWaitHandle eventWaitHandle = new ManualResetEvent(false);
        public String result;
        public String word;
    }

    private static void PerformUserWorkItem( Object stateObject )
    {
        State state = stateObject as State;

        if(state != null)
        {
            Uri address = new Uri("http://en.wikipedia.org/w/api.php?action=opensearch&search=" + state.word);
            HttpWebRequest request = WebRequest.Create(address) as HttpWebRequest;
            HttpWebResponse responce = (HttpWebResponse)request.GetResponse();

            StreamReader myStreamReader = new StreamReader(responce.GetResponseStream(), Encoding.GetEncoding(1251));
            state.result = myStreamReader.ReadToEnd();

            state.eventWaitHandle.Set(); 
        }
    }

    public static String DoWork(String _word)
    {
        State state = new State();
        state.word = _word;

        ThreadPool.QueueUserWorkItem(PerformUserWorkItem, state);
        state.eventWaitHandle.WaitOne();
        return state.result;                   
    }     
}

问题

当用户按下 tbWord 中的键时，主窗体会卡住并等待 Wiki 类完成所有工作。

如何异步运行 DoWork？

Answer 1

或者像这样使用 TPL:

private void tbWord_TextChanged(object sender, TextChangedEventArgs e) 
 { 
    Task.Factory.StartNew(() =>
    {
        return Wiki.DoWrok(tbWord.Text);
    }).ContinueWith(taskState =>
    {
        tbResponce.Text = taskState.Result;
    }, TaskScheduler.FromCurrentSynchronizationContext());
 } 

参见:http://msdn.microsoft.com/en-us/library/dd997394.aspx