从桌面移动到设备：多线程和用户界面(2)

class MyForm : Form{
  ListBox lbData ;
  MyForm() {
    InitializeComponent(); // Create form controls

    Thread t = new Thread(new ThreadStart(Work1_));
    t.Start() ; // Runs Work1_ on a background thread
  }

private Queue qData = new Queue(); // Visible to all member functions on all threads

  void Work1_(){
    // Wrap AddItem in delegate
    EventHandler eh = new EventHandler(AddItem);
    StreamReader rdr1 = new StreamReader(@"\My Documents\DataFile.dat");
    string line = rdr1.ReadLine();
    while(line != null) {
      lock(qData){ // Synchronize queue acess
        qData.Enqueue(line); // Store line value in queue
      }
      lbData.Invoke(eh); // Transfer control to thread that created lbData
      line = rdr1.ReadLine();
    }
  } 

  void AddItem(object o, EventArgs e)
  {
    string line = null;
    lock(qData){ // Synchronize queue acess
      line = (string)qData(); // Get data from queue
    }
    lbData.Items.Add(line); // Update list box
  }
}

void Work1_(){
    // Wrap AddItem in delegate
    EventHandler eh = new EventHandler(AddItem);
    StreamReader rdr1 = new StreamReader(@"\My Documents\DataFile.dat");
    string line = rdr1.ReadLine();
    while(line != null) {
      lbData.Invoke(eh, new object[]{line, EventArgs.Empty}); // Pass to AddItem
      line = rdr1.ReadLine();
    }
  } 

  // o receives the reference to line, e receives EventArgs.Empty
  void AddItem(object o, EventArgs e)
  {
    string line = (string) o; // Upcast o
    lbData.Items.Add(line);  // Add to list box
  }