.NET并行计算和并发3-Invoke

Control.Invoke 方法 (Delegate)

在拥有此控件的基础窗口句柄的线程上执行指定的委托。

Invoke方法搜索沿控件的父级链，直到它找到的控件或窗口具有一个窗口句柄；

如果尚不存在当前控件的基础窗口句柄，或者找不到任何合适的句柄，Invoke方法

将会引发异常。

例子

     public class MyFormControl : Form
     {
         public delegate void AddListItem();

         public AddListItem myDelegate;
         private Thread myThread;
         private ListBox myListBox;

         public MyFormControl()
         {
             var myButton = new Button();
             myListBox = new ListBox();
             myButton.Location = new Point(72, 160);
             myButton.Size = new Size(152, 32);
             myButton.TabIndex = 1;
             myButton.Text = "Add items in list box";
             myButton.Click += new EventHandler(Button_Click);
             myListBox.Location = new Point(48, 32);
             myListBox.Name = "myListBox";
             myListBox.Size = new Size(200, 95);
             myListBox.TabIndex = 2;
             ClientSize = new Size(292, 273);
             Controls.AddRange(new Control[] { myListBox, myButton });
             Text = " 'Control_Invoke' example";
             myDelegate = new AddListItem(AddListItemMethod);
         }

         public void AddListItemMethod()
         {
             String myItem;
             for (int i = 1; i < 6; i++)
             {
                 myItem = "MyListItem" + i.ToString();
                 myListBox.Items.Add(myItem);
                 myListBox.Update();
                 Thread.Sleep(3000);
             }
         }

         private void Button_Click(object sender, EventArgs e)
         {
             myThread = new Thread(new ThreadStart(ThreadFunctionRight));
             myThread.Start();
         }
     }
 

关键

         private void ThreadFunctionWrong()
         {
             //if direct call myDelegate(), it would throw an exception
             myDelegate();
         }

         private void ThreadFunctionRight()
         {
             //right way: must run at thead that creates myListBox control.
             // Execute the specified delegate on the thread that owns
             // 'myListBox' control's underlying window handle.
             this.Invoke(this.myDelegate);
         }