为什么C#接口中不能声明async异步函数（转载）

Unable to declare Interface “ async Task<myObject> MyMethod(Object myObj); ”

 

问

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I'm unable to declare

interface IMyInterface
{
   async Task<myObject> MyMethod(Object myObj);
}

The compiler tells me:

• The modifier async isn't valid for this item
• The async modifier can only be used for methods that have a body

Is this something that should be implemented, or does the nature of async & await prohibit this from ever occurring?

 

 

答1

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Whether a method is implemented using async/await or not is an implementation detail. How the method should behave is a contract detail, which should be specified in the normal way.
Note that if you make the method return a Task or a Task<T>, it's more obvious that it's meant to be asynchronous, and will probably be hard to implement without being asynchronous.

From How to force async child overrides in C# 5.0

 

 

答2

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Whether or not your implementation is async, has no relevance to your interface. In other words, the interface cannot specify that a given method must be implemented in an asynchronous way.
Just take async out of your interface and it will compile; however, there is no way to enforce asynchronous implementation just by specifying an interface.

 

 

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