# concurrency

**Repository Path**: diywindow/concurrency

## Basic Information

- **Project Name**: concurrency
- **Description**: 并发、异步、同步、async、await
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 1
- **Created**: 2016-10-10
- **Last Updated**: 2020-12-19

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

async和await
---------------
使用async后面一定会加Task<实体对象>
await会将Task<实体对象>里的“实体对象”提取出来返回。


等待一组任务完成
---------------

```
public async Task<ActionResult> IndexAsync()
        {
            var firstTask = getTaskInt(1);
            var thireTask = getTaskInt(3);
            var secondTask = getTaskInt(2);
            var tasks = new[] { firstTask, thireTask, secondTask };
            await Task.WhenAll(tasks);
            int firstVal = firstTask.Result;
            int secondVal = secondTask.Result;
            int thireVal = thireTask.Result;


        }
private static async Task<int> getTaskInt(int val)
        {
            await Task.Delay(TimeSpan.FromSeconds(val));
            return val;
        }

//或者：

public async Task<ActionResult> Index()
{
    //Services.FeedService feedService = new Services.FeedService();
    Stopwatch timer = Stopwatch.StartNew();
    timer.Start();
    var feeds = await GetFeeds();
    timer.Stop();
    feeds.TimeTaken = timer.ElapsedMilliseconds;
    return View(feeds);
}

public async Task<Dashboard> GetFeeds()
{
    var emails = new HttpClient().GetStringAsync("http://localhost:18545/api/Emails");
    var myTasks = new HttpClient().GetStringAsync("http://localhost:18545/api/Tasks");
    var notes = new HttpClient().GetStringAsync("http://localhost:18545/api/Notes");
    var bookmarks = new HttpClient().GetStringAsync("http://localhost:18545/api/Bookmarks");

    await Task.WhenAll(emails, myTasks, notes, bookmarks);

    Dashboard dash = new Dashboard();
    dash.Emails = Deserialize<Email>(emails.Result);
    dash.Bookmarks = Deserialize<Bookmark>(bookmarks.Result);
    dash.Notes = Deserialize<Note>(notes.Result);
    dash.Tasks = Deserialize<MyTask>(myTasks.Result);
    return dash;
}

```

//await Task.Delay(1000).ConfigureAwait(false);
ConfigureAwait(false)的作用是await执行完后，下一行代码使用新线程执行，如果await上一行代码的上下文是UI线程，
不添加ConfigureAwait(false)，await执行完后,下一行代码继续使用UI线程。