Async Contructors

[bilal-fazlani]

I am proposing something like this:

public class MyClass
{
  public async Task<MyClass>()
  {
    await doSomeAsyncSetupWork();
  }
}

class Program
{
  public static async Task main(string[] args)
  {
    MyClass myClass = await new MyClass();
  }
}

Without this feature, it would have to be something like this.

Workaround 1:

public class MyClass
{
  public MyClass()
  {
    doSomeAsyncSetupWork().Wait();
  }
}

class Program
{
  public static async Task main(string[] args)
  {
    MyClass myClass = new MyClass();
  }
}

Or Workaround 2:

public class MyClass
{
  public MyClass()
  {
  }

  public async Task Setup()
  {
    await doSomeAsyncSetupWork();
  }
}

class Program
{
  public static async Task main(string[] args)
  {
    MyClass myClass = new MyClass();
    await myClass.Setup();
  }
}

Both of these workarounds have some problem. The former obviously because of it's blocking behaviour.

The issue with latter is, I even though Setup() in a mandatory requirement for object to exist and function correctly, I still have to call it explicitly whenever I create instance of object, otherwise, the the object is incomplete and won't function and throw runtime exceptions.

[benaadams]

Workaround 3:

public class MyClass
{
    private Task _initalization;
    
    public MyClass()
    {
        _initalization = doSomeAsyncSetupWork(); 
    }
    
    public async Task WhenInitalizedAsync()
    {
      await _initalization;
    }
}

class Program
{
  public static async Task main(string[] args)
  {
    MyClass myClass = new MyClass();
    await myClass.WhenInitalizedAsync();
  }
}

Workaround 4:

public class MyClass
{
    private Task _initalization;
    
    private MyClass()
    {
        _initalization = doSomeAsyncSetupWork(); 
    }
    
    public async static Task<MyClass> CreateAsync()
    {
        MyClass myClass = MyClass();
        await myClass._initalization;
        return myClass;
    }
}

class Program
{
  public static async Task main(string[] args)
  {
    MyClass myClass = await MyClass.CreateAsync();
  }
}

Last one ensures initalization

[yaakov-h]

Duplicate of #419, though with different requested syntax.