c# - 如何在我的 ASP.NET MVC 应用程序中异步查询 ParseObject 集合？

Question

我尝试了以下方法。目前，我只是想读取控制台中查询的对象集合。根据指南，首选异步查询：http: //docs.parseplatform.org/dotnet/guide/#queries

public class IndexModel : PageModel
    {
        public void OnGet()
        {
            Task<int> task = HandleMessagesAsync();
            task.Start();

        }

        private async Task<int> HandleMessagesAsync()
        {
            var query = ParseObject.GetQuery("Message");
            IEnumerable<ParseObject> results = await query.FindAsync();

            Console.WriteLine(results);

            throw new NotImplementedException();
        }
    }

我收到以下错误：

System.InvalidOperationException: 'Start may not be called on a promise-style task.'

Answer 1

根据本指南，该Task课程会自动启动：https ://social.msdn.microsoft.com/Forums/vstudio/en-US/70f82b79-188e-4e91-8f86-b5a9382663fb/problem-with-taskstart?forum=netfxbcl

无需调用.Start();

public class IndexModel : PageModel
    {
        public void OnGet()
        {
            Task<int> task = HandleMessagesAsync();
        }

        private async Task<int> HandleMessagesAsync()
        {
            var query = ParseObject.GetQuery("Message");
            IEnumerable<ParseObject> results = await query.FindAsync();
            var count = await query.CountAsync();

            Debug.WriteLine("# Message: " + count);

            throw new NotImplementedException();
        }
    }

我曾经Debug.WriteLine("# Message: " + count);确保从我的数据库中查询到正确数量的 Message 对象。