相关疑难解决方法(0)

asp.net 4.5中有一个新的应用程序设置

<add key="aspnet:UseTaskFriendlySynchronizationContext" value="true" />

像这样的代码可以在asp.net 4.0中运行

protected void Button1_Click(object sender, EventArgs e)
{
    CallAysnc();
}

public void CallAysnc()
{
    AsyncOperation asyncOp = AsyncOperationManager.CreateOperation(Guid.NewGuid().ToString());

    WebClient client = new WebClient();
    client.DownloadStringCompleted += (object sender, DownloadStringCompletedEventArgs e) =>
    {
        asyncOp.PostOperationCompleted(CallCompleted, e.Result);
    };
    client.DownloadStringAsync(new Uri("http://www.google.com"));
}

private void CallCompleted(object args)
{
    Response.Write(args.ToString());
}

但它在asp.net 4.5中不起作用,当我删除新的appsetting时,它再次起作用!

那么"UseTaskFriendlySynchronizationContext"的含义是什么？