C# Ninject: How to bind to method async

Question

I am using Ninject 3.2.2.0 and I am trying to bind an async method.

This is what I got so far:

kernel.Bind<Task<MyInterface>>().ToMethod(async ctx =>
{
   var someData = await DoSomethingAsync();
   return new SomethingElse(someData);
}).InRequestScope();

My method DoSomethingAsync never gets called. I believe it's not being called because MyInterface is being requested, not Task<MyInterface> .

Any ideas?

Answer 1

The construction of your object graph should be reliable and fast . This excludes doing anything that is I/O related. This means that you should not do anything that is asynchronous at all .

Instead anything that is slow, unreliable or asynchronous should be postponed untill after the object graph is constructed.

Answer 2

I ended up making my binding sync

kernel.Bind<MyInterface>().ToMethod(ctx =>
{
   var someData = DoSomethingSync(); // <-- Made this one sync, see method below
   return new SomethingElse(someData);
}).InRequestScope();

Here is the 'magic'. I changed my method from:

private async Task<string> DoSomethingAsync() {
  var result = await DoSomethingElseAsync();
  return result;
}

To

private string DoSomethingSync() {
   string result = null;

   var runSync = Task.Factory.StartNew(async () => {
      result = await DoSomethingElseAsync();
   }).Unwrap();
   runSync.Wait();

   return result;
}

I know performance is affected because of the context switch, but at least it works as expected and you can be sure that it won't deadlock.