WPF跨线程更新UI的3种方法

很好的一篇文章，讲得很透彻：WPF Threads: Build More Responsive Apps With The Dispatcher

总结一下，跨线程更新UI的3种方法：

1）Dispatcher

1. void ProgressChanged(object sender, DownloadProgressChangedEventArgs e)
   
2. {
   
3.       this.Dispatcher.Invoke(DispatcherPriority.Normal, new System.Windows.Forms.MethodInvoker(delegate()
   
4.       {
   
5.           this.ProgressBar.Value = e.ProgressPercentage;
   
6.       }));
   
7. }
   

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2） DispatcherTimer

1. // Create a Timer with a Normal Priority
   
2. 
   
3. _timer = new DispatcherTimer();
   
4. 
   
5. 
   
6. 
   
7. // Set the Interval to 2 seconds
   
8. 
   
9. _timer.Interval = TimeSpan.FromMilliseconds(2000);
   
10. 
    
11. 
    
12. 
    
13. // Set the callback to just show the time ticking away
    
14. 
    
15. // NOTE: We are using a control so this has to run on
    
16. 
    
17. // the UI thread
    
18. 
    
19. _timer.Tick += new EventHandler(delegate(object s, EventArgs a)
    
20. 
    
21. {
    
22. 
    
23.     statusText.Text = string.Format(
    
24. 
    
25.         "Timer Ticked:  {0}ms", Environment.TickCount);
    
26. 
    
27. });
    
28. 
    
29. 
    
30. 
    
31. // Start the timer
    
32. 
    
33. _timer.Start();
    

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3）BackgroundWorker

1. BackgroundWorker _backgroundWorker = new BackgroundWorker();
   
2. 
   
3. ...
   
4. 
   
5. // Set up the Background Worker Events
   
6. 
   
7. _backgroundWorker.DoWork += _backgroundWorker_DoWork;
   
8. 
   
9. backgroundWorker.RunWorkerCompleted +=
   
10. 
    
11.     _backgroundWorker_RunWorkerCompleted;
    
12. 
    
13. 
    
14. 
    
15. // Run the Background Worker
    
16. 
    
17. _backgroundWorker.RunWorkerAsync(5000);
    
18. 
    
19. 
    
20. 
    
21. ...
    
22. 
    
23. 
    
24. 
    
25. // Worker Method
    
26. 
    
27. void _backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
    
28. 
    
29. {
    
30. 
    
31.     // Do something
    
32. 
    
33. }
    
34. 
    
35. 
    
36. 
    
37. // Completed Method
    
38. 
    
39. void _backgroundWorker_RunWorkerCompleted(
    
40. 
    
41.     object sender,
    
42. 
    
43.     RunWorkerCompletedEventArgs e)
    
44. 
    
45. {
    
46. 
    
47.     if (e.Cancelled)
    
48. 
    
49.     {
    
50. 
    
51.         statusText.Text = "Cancelled";
    
52. 
    
53.     }
    
54. 
    
55.     else if (e.Error != null)
    
56. 
    
57.     {
    
58. 
    
59.         statusText.Text = "Exception Thrown";
    
60. 
    
61.     }
    
62. 
    
63.     else
    
64. 
    
65.     {
    
66. 
    
67.         statusText.Text = "Completed";
    
68. 
    
69.     }
    
70. 
    
71. }
    

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