blocks|key|4476120|text|将其更改为|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4476121|int+task+=+await+CastFuncToTask<int>(()=>TestFunc(2));|code-block|syntax|javascript|4476122|在您的代码中，为CastFuncToTask提供的输入是一个int(+TestFunc返回的内容)。但它需要一个委托Func<T>。|offset|length|style|CODE|4476123|entityMap^0|0|0|8|E|U|3|Z|8|1M|7|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]|$I|V|J|W|K|L]|$I|X|J|Y|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|N|$]]

change it to

<pre><code>int task = await CastFuncToTask&lt;int&gt;(()=&gt;TestFunc(2));
</code></pre>

In your code the input provided for <code>CastFuncToTask</code> is an <code>int</code>(what <code>TestFunc</code> returns.) but it needs a delegate <code>Func&lt;T&gt;</code>.

blocks|key|4475455|text|我的方法是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4475456|public+Task<int>+SetOffAsync()
{
++++return+Task<int>.Factory.StartNew(()+=>
++++{+
++++++++/*do+something+else*/
++++++++return+42;
++++});
}|code-block|syntax|javascript|4475457|你可以这样叫它：|4475458|int+var+=+await+SetOffAsync();|4475459|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

my method is this :

<pre><code>public Task&lt;int&gt; SetOffAsync()
{
 return Task&lt;int&gt;.Factory.StartNew(() =&gt;
 { 
 /*do something else*/
 return 42;
 });
}
</code></pre>

and you can call this :

<pre><code>int var = await SetOffAsync();
</code></pre>

blocks|key|4475487|text|等待Task.Run(()+=>+obj.functionname())；|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4475488|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

await Task.Run(() => obj.functionname());

blocks|key|4476155|text|对于一个windows+forms应用程序，我确认第一个调用阻塞了第二个调用，所以最好的解决方案是使用带有lambda表达式的Task.Run()。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4476156|++++private+async+void+button1_Click(object+sender,+EventArgs+e)
++++{
++++++++button1.Text+=+"...";
++++++++var+result+=+await+Task.FromResult(TestFunc(2));
++++++++button1.Text+=+result.ToString();
++++}

++++private+async+void+button2_Click(object+sender,+EventArgs+e)
++++{
++++++++button2.Text+=+"...";
++++++++var+result+=+await+Task.Run(()+=>+TestFunc(2));
++++++++button2.Text+=+result.ToString();
++++}

++++private+int+TestFunc(int+x)
++++{
++++++++System.Threading.Thread.Sleep(5000);
++++++++return+x;
++++}|code-block|syntax|javascript|4476157|编译器不能知道您不想计算TestFunc(2)，而是将其用作委托，并将首先执行该方法，Task.FromResult将仅将return+value包装在任务中。这不是你想要的。|4476158|entityMap^0|1R|A|0|0|1P|C|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|N|$]]

With a windows forms application I confirmed that the first call is blocking the second isn't. So the best solution would be to use <code>Task.Run()</code> with a lambda expression.

<pre><code> private async void button1_Click(object sender, EventArgs e)
 {
 button1.Text = "...";
 var result = await Task.FromResult(TestFunc(2));
 button1.Text = result.ToString();
 }

 private async void button2_Click(object sender, EventArgs e)
 {
 button2.Text = "...";
 var result = await Task.Run(() =&gt; TestFunc(2));
 button2.Text = result.ToString();
 }

 private int TestFunc(int x)
 {
 System.Threading.Thread.Sleep(5000);
 return x;
 }
</code></pre>

The compiler can not know that you don't want to evaluate TestFunc(2) but use it as a delegate and will just execute the method first and Task.FromResult will just wrap a <code>return value</code> in a Task. This is not what you want.

blocks|key|4476386|text|下面的代码可能会对其他人有所帮助：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4476387|注意:+GenericMethod是参数名，我们将其作为泛型类型的输入函数(T1)和输出函数(T2)传递。任务工厂将提供运行任务所需的访问权限。|4476388|++++public+async+Task<T2>+GenericAsyncCall<T1,+T2>(Func<T1,+T2>+GenericMethod,+T1+input)
++++{
++++++++var+_output+=+await+Task.Factory.StartNew(()+=>+{
++++++++++++var+output+=+GenericMethod.Invoke(input);
++++++++++++return+output;
++++++++});

++++++++return+(T2)_output;
++++}|code-block|syntax|javascript|4476389|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Below code may help others:

Note: GenericMethod is parameter name which we are passing as Func with Input (T1) and output (T2) of generic Type.
Task Factory will provide necessary access to run your task.

<pre><code> public async Task&lt;T2&gt; GenericAsyncCall&lt;T1, T2&gt;(Func&lt;T1, T2&gt; GenericMethod, T1 input)
 {
 var _output = await Task.Factory.StartNew(() =&gt; {
 var output = GenericMethod.Invoke(input);
 return output;
 });

 return (T2)_output;
 }
</code></pre>

blocks|key|4476427|text|问题是CastFuncToTask是同步运行的。如果Func是无参数的，你可以这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4476428|public+static+Task<T>+ToTask(this+Func<T>+func)+=>+Task.Factory.StartNew(()+=>+func());|offset|length|style|CODE|4476429|无论如何，我们可以使用TaskCompletionSource并返回我们想要的东西，而不管方法是什么。假设我们有Action而不是Func|4476430|public+static+Task<string>+ToTask(this+Action+action)++++
{++++TaskCompletionSource<string>+taskCompletionSource+=+new+
+++++++++++TaskCompletionSource<string>();
+++++++++++string+result+=+null;
+++++++++++try
+++++++++++{
+++++++++++++++Task.Factory.StartNew(()+=>+action());
+++++++++++}
+++++++++++catch+(Exception+ex)
+++++++++++{
+++++++++++++++result+=+ex.Message;
+++++++++++}
+++++++++++taskCompletionSource.SetResult(result);
+++++++++++return+taskCompletionSource.Task;
+++++++}|code-block|syntax|javascript|4476431|entityMap^0|0|0|2F|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@$D|S|E|T|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|U|8|@]|9|@]|A|$]]|$1|J|3|K|5|L|7|V|8|@]|9|@]|A|$M|N]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

The problem is that CastFuncToTask runs synchronously.
if Func is parameterless you can do something like this:
<code>public static Task&lt;T&gt; ToTask(this Func&lt;T&gt; func) =&gt; Task.Factory.StartNew(() =&gt; func());</code>
Anyway we can play with TaskCompletionSource and return something we want regardless of the method. Lets say we have Action instead of Func
<pre><code>public static Task&lt;string&gt; ToTask(this Action action) 
{ TaskCompletionSource&lt;string&gt; taskCompletionSource = new 
 TaskCompletionSource&lt;string&gt;();
 string result = null;
 try
 {
 Task.Factory.StartNew(() =&gt; action());
 }
 catch (Exception ex)
 {
 result = ex.Message;
 }
 taskCompletionSource.SetResult(result);
 return taskCompletionSource.Task;
 }
</code></pre>

The goal of the following code is to cast any given function into an awaitable function. The idea is to use it when fetching the data from the db, giving the code the flexibility to either use the synchronous fetch functions (an imposition of my current ORM), or use the very same functions as async.

I am aware that there could be many things wrong with the concept behind code. By now I was just trying to get rid of the compiler errors so I can run the code and check the behavior. But of course I am open to discuss the concept beforehand, and if the whole idea behind it is wrong then use my time more efficiently looking for another solution.

<pre><code>async static void Main()
{
 // The following line gives a compiler error:
 // Error 1 The best overloaded method match for 'CastFuncToTask&lt;int&gt;(System.Func&lt;int&gt;)' has some invalid arguments 
 int task = await CastFuncToTask&lt;int&gt;(TestFunc(2));
}

private static Task&lt;T&gt; CastFuncToTask&lt;T&gt;(Func&lt;T&gt; func)
{
 TaskCompletionSource&lt;T&gt; taskCompletionSource = new TaskCompletionSource&lt;T&gt;();
 T result = func.Invoke();
 taskCompletionSource.SetResult(result);
 return taskCompletionSource.Task;
}

private static int TestFunc(int testInt) 
{
 return testInt * 2;
}
</code></pre>

Convert any given function into an awaitable task

数据库

编译器

以下代码的目标是将任何给定的函数转换为可等待的函数。这个想法是在从数据库获取数据时使用它，让代码可以灵活地使用同步获取函数(这是我当前ORM的强制要求)，或者使用与异步完全相同的函数。我知道代码背后的概念可能有很多问题。到目前为止，我只是试图摆脱编译器错误，这样我就可以运行代码并检查行为。但当然，我愿意事先讨论这个概念，如果它背后的整个想法是错误的，那么就更有效地利用我的时间寻找另一个解决方案。a

问将任何给定的函数转换为可等待的任务
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