一个简单的例子看明白 async await Task

测试代码：

  1 using system;
  2 using system.collections.generic;
  3 using system.componentmodel;
  4 using system.data;
  5 using system.drawing;
  6 using system.linq;
  7 using system.text;
  8 using system.threading;
  9 using system.threading.tasks;
 10 using system.windows.forms;
 11 using utils;
 12 
 13 namespace test
 14 {
 15     public partial class form1 : form
 16     {
 17         public form1()
 18         {
 19             initializecomponent();
 20         }
 21 
 22         private void form1_load(object sender, eventargs e)
 23         {
 24 
 25         }
 26 
 27         /// <summary>
 28         /// 执行任务
 29         /// </summary>
 30         public string dowork(string str)
 31         {
 32             thread.sleep(3000); //模拟延迟 比如网络请求 用了3000毫秒
 33             return "输出：" + str;
 34         }
 35 
 36         /// <summary>
 37         /// 执行任务
 38         /// </summary>
 39         public task<string> doworkbytask(string str)
 40         {
 41             return task.run(() =>
 42             {
 43                 thread.sleep(3000); //模拟延迟 比如网络请求 用了3000毫秒
 44                 return "输出：" + str;
 45             });
 46         }
 47 
 48         /// <summary>
 49         /// 测试1
 50         /// </summary>
 51         private async void button1_click(object sender, eventargs e)
 52         {
 53             logtimeutil logtime = new logtimeutil();
 54 
 55             var t1 = doworkbytask("测试值1");
 56 
 57             var t2 = doworkbytask("测试值2");
 58 
 59             string r1 = await t1;
 60 
 61             textbox1.appendtext(r1 + "\r\n");
 62 
 63             string r2 = await t2;
 64 
 65             textbox1.appendtext(r2 + "\r\n");
 66 
 67             logtime.logtime("耗时", textbox1);
 68         }
 69 
 70         /// <summary>
 71         /// 测试2 
 72         /// 
 73         /// 等效于 测试1
 74         /// </summary>
 75         private void button2_click(object sender, eventargs e)
 76         {
 77             task.run(() => //如果不加task.run，界面会卡
 78             {
 79                 logtimeutil logtime = new logtimeutil();
 80 
 81                 task<string> t1 = task.run<string>(() => { return dowork("测试值1"); });
 82                 task<string> t2 = task.run<string>(() => { return dowork("测试值2"); });
 83 
 84                 task.waitall(t1, t2);
 85 
 86                 this.invoke(new action(() => //线程中修改控件数据要使用invoke
 87                 {
 88                     textbox1.appendtext(t1.result + "\r\n");
 89                     textbox1.appendtext(t2.result + "\r\n");
 90                 }));
 91 
 92                 logtime.logtime("耗时", textbox1);
 93             });
 94         }
 95 
 96         /// <summary>
 97         /// 测试3 
 98         /// </summary>
 99         private async void button3_click(object sender, eventargs e)
100         {
101             logtimeutil logtime = new logtimeutil();
102 
103             var r1 = await doworkbytask("测试值1");
104 
105             textbox1.appendtext(r1 + "\r\n");
106 
107             var r2 = await doworkbytask("测试值2");
108 
109             textbox1.appendtext(r2 + "\r\n");
110 
111             logtime.logtime("耗时", textbox1);
112         }
113 
114         /// <summary>
115         /// 测试4
116         /// 
117         /// 等效于 测试3
118         /// </summary>
119         private void button4_click(object sender, eventargs e)
120         {
121             task.run(() => //如果不加task.run，界面会卡
122             {
123                 logtimeutil logtime = new logtimeutil();
124 
125                 task<string> t1 = task.run<string>(() => { return dowork("测试值1"); });
126                 t1.wait();
127                 this.invoke(new action(() => //线程中修改控件数据要使用invoke
128                 {
129                     textbox1.appendtext(t1.result + "\r\n");
130                 }));
131 
132                 task<string> t2 = task.run<string>(() => { return dowork("测试值2"); });
133                 t2.wait();
134                 this.invoke(new action(() => //线程中修改控件数据要使用invoke
135                 {
136                     textbox1.appendtext(t2.result + "\r\n");
137                 }));
138 
139                 logtime.logtime("耗时", textbox1);
140             });
141         }
142 
143     }
144 }

测试输出：

附 logtimeutil.cs：

using system;
using system.collections.generic;
using system.linq;
using system.text;
using system.threading.tasks;
using system.windows.forms;

namespace utils
{
    /// <summary>
    /// 记录耗时
    /// </summary>
    public class logtimeutil
    {
        private datetime _lasttime;

        public logtimeutil()
        {
            _lasttime = datetime.now;
        }

        /// <summary>
        /// 记录耗时
        /// </summary>
        public void logtime(string msg)
        {
            double d = datetime.now.subtract(_lasttime).totalseconds;
            logutil.log(msg + "，耗时：" + d.tostring("0.000") + " 秒");
        }

        /// <summary>
        /// 记录耗时
        /// </summary>
        public void logtime(string msg, textbox txt)
        {
            double d = datetime.now.subtract(_lasttime).totalseconds;
            msg = msg + "，耗时：" + d.tostring("0.000") + " 秒\r\n";
            if (txt.invokerequired)
            {
                txt.invoke(new action(() =>
                {
                    txt.appendtext(msg);
                }));
            }
            else
            {
                txt.appendtext(msg);
            }
        }
    }
}