MethodInvoker和Invoker

清疚 2022-08-04 00:35 312阅读 0赞

using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Data;
    using System.Drawing;
    using System.Linq;
    using System.Text;
    using System.Threading;
    using System.Windows.Forms;
    
    namespace SQL_browser
    {
        public partial class Form1 : Form
        {
            public Form1()
            {
                InitializeComponent();
            }
    
            private void button1_Click(object sender, EventArgs e)
            {
                /*
                 * 1.MethodInvoke和Action都是方法返回类型为空的委托.
                 * 2.MethodInvoker的原型定义为---> public delegate void MethodInvoker();
                 */
                //Delegate d1 = (MethodInvoker)delegate { };
                //Delegate d2 = (MethodInvoker)(() => { });
    
                //Delegate d3 = (Action)delegate { };
                //Delegate d4 = (Action)(() => { });
    
                Thread t = new Thread(() =>
                {
                    Enumerable.Range(1, 10).ToList().ForEach(x =>
                    {
                        if (listBox1.InvokeRequired)
                        {
                            listBox1.Invoke((Action)(() =>
                            {
                                listBox1.Items.Add(string.Format("[{0}] executed 【  (Action)(() => {
       { }})  】", x));
                            }));
                        }
                    });
                    Enumerable.Range(11, 10).ToList().ForEach(x =>
                    {
                        if (listBox1.InvokeRequired)
                        {
                            listBox1.Invoke((Action)delegate
                            {
                                listBox1.Items.Add(string.Format("[{0}] executed 【  (Action)delegate {
       { }}  】", x));
                            });
                        }
                    });
                    Enumerable.Range(21, 10).ToList().ForEach(x =>
                    {
                        if (listBox1.InvokeRequired)
                        {
                            listBox1.CCInvoke(() =>     //使用lambda表达式
                            {
                                listBox1.Items.Add(string.Format("[{0}] executed 【  lambda  】", x));
                            });
                            listBox1.CCInvoke(delegate  //使用委托
                            {
                                listBox1.Items.Add(string.Format("[{0}] executed 【  delegate  】", x));
                            });
                        }
                    });
                });
                t.Start();
            }
        }
    
            private void button2_Click(object sender, EventArgs e)
            {
                listBox1.Items.Clear();
    
                Task taskWithFactoryAndState1 = Task.Factory.StartNew<List<int>>((stateObj) =>
                {               
                    List<int> ints = new List<int>();
                    for (int i = 0; i < (int)stateObj; i++)
                    {
                        ints.Add(i);
                    }
                    return ints;
                }, 100).ContinueWith(ant =>
                {                
                    listBox1.DataSource = ant.Result;
                }, TaskScheduler.FromCurrentSynchronizationContext());
            }
    
        public static class ControlExtend
        {
            public static void CCInvoke(this Control control, Action action)
            {
                if (control.IsDisposed)
                return;
            try
            {
                control.Invoke((Delegate)action);
            }
            catch (ObjectDisposedException ode)
            {
    
            }
            catch (InvalidOperationException iox)
            {
    
            }
            }
        }
    }
    </int></int></int>

![SouthEast][]

**注意：button2\_Click的方法会阻塞UI线程，如果数据量大或者里面的方法很耗时，界面会有卡死假象，比如窗体拖不动**

[SouthEast]: /images/20220731/e203925f377246a58bad94c27d0a6788.png