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c#async-ctp

How to write simple async method?


Using latest CTP5 with async/await keywords, I wrote some code, which apparently cannot compile:

 class Program
    {
        public class MyClass
        {
            async public Task<int> Test()
            {
                var result = await TaskEx.Run(() =>
                    {
                        Thread.Sleep(3000);
                        return 3;
                    });
                return result;
            }
        }

        static void Main(string[] args)
        {
            var myClass = new MyClass();

            //The 'await' operator can only be used in a method or lambda marked with the 'async' modifier error ??!!
            int result = await myClass.Test();

            Console.ReadLine();
        }
    }

What is th reason of "The 'await' operator can only be used in a method or lambda marked with the 'async' modifier error?" (I've selected the line which Visual Studio point me to)


Solution

  • I don't know if you can mark Main as async, but you need to include the async keyword in the declaration of any method that uses await. For example:

    public async void DoStuffAsync ()
    {
        var myClass = new MyClass ();
    
        int result = await myClass.TestAsync ();
    }