,
http =
http,
url =
url,
time =
time,
_builder = AsyncTaskMethodBuilder<
string>
.Create(),
_state = -
1
};
stateMachine._builder.Start(ref stateMachine);
return stateMachine._builder.Task;
}
private sealed class GetUrlStringAsyncdStateMachine : IAsyncStateMachine
{
public int _state;
public MyAsyncTest _this;
private string _str1;
public AsyncTaskMethodBuilder<string> _builder;
private TaskAwaiter taskAwaiter1;
private TaskAwaiter<string> taskAwaiter2;
//异步方法的三个形参都到这里来了
public HttpClient http;
public int time;
public string url;
private void MoveNext()
{
string str;
int num = this._state;
try
{
TaskAwaiter awaiter;
MyAsyncTest.GetUrlStringAsyncdStateMachine d__;
string str2;
switch (num)
{
case 0:
break;
case 1:
goto Label_00CD;
default:
//这里是异步方法 await Task.Delay(time);的具体实现
awaiter = Task.Delay(this.time).GetAwaiter();
if (awaiter.IsCompleted)
{
goto Label_0077;
}
this._state = num = 0;
this.taskAwaiter1 = awaiter;
d__ = this;
this._builder.AwaitUnsafeOnCompleted<TaskAwaiter, MyAsyncTest.GetUrlStringAsyncdStateMachine>(ref awaiter, ref d__);
return;
}
awaiter = this.taskAwaiter1;
this.taskAwaiter1 = new TaskAwaiter();
this._state = num = -1;
Label_0077:
awaiter.GetResult();
awaiter = new TaskAwaiter();
//这里是异步方法await http.GetStringAsync(url);的具体实现
TaskAwaiter<string> awaiter2 = this.http.GetStringAsync(this.url).GetAwaiter();
if (awaiter2.IsCompleted)
{
goto Label_00EA;
}
this._state = num = 1;
this.taskAwaiter2 = awaiter2;
d__ = this;
this._builder.AwaitUnsafeOnCompleted<TaskAwaiter<string>, MyAsyncTest.GetUrlStringAsyncdStateMachine>(ref awaiter2, ref d__);
return;
Label_00CD:
awaiter2 = this.taskAwaiter2;
this.taskAwaiter2 = new TaskAwaiter<string>();
this._state = num = -1;
Label_00EA:
str2 = awaiter2.GetResult();
awaiter2 = new TaskAwaiter<string>();
this._str1 = str2;
str = this._str1;
}
catch (Exception exception)
{
this._state = -2;
this._builder.SetException(exception);
return;
}
this._state = -2;
this._builder.SetResult(str);
}
[DebuggerHidden]
private void SetStateMachine(IAsyncStateMachine stateMachine)
{
}
}
明显多个异步等待执行的时候就是在不断调用状态机中的MoveNext()方法。经验来至我们之前分析过的IEumerable,不过今天的这个明显复杂度要高于以前的那个。猜测是如此，我们还是来验证下事实：
