c# - 错误 'Device' 在 Controller MVC 中不包含 'GetAwaiter' 的定义

Question

在接下来的代码中

 [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<ActionResult> Create([Bind(Include = "DispositivoID,Nombre,ClaveDispositivo,Activo,EmpresaID")] Modelo.Dispositivo dispositivo)
    {
        if (ModelState.IsValid)
        {
            //string deviceId = "minwinpc";
            Device device;
            try
            {
                device =  await registryManager.AddDeviceAsync(new Device(dispositivo.Nombre)).Result;

            }
            catch (DeviceAlreadyExistsException)
            {
                device = await registryManager.GetDeviceAsync(dispositivo.Nombre).Result;
            }

            dispositivo.ClaveDispositivo = device.Authentication.SymmetricKey.PrimaryKey;
            db.Dispositivos.Add(dispositivo);
            db.SaveChanges();
            return RedirectToAction("Index");
        }

        ViewBag.EmpresaID = new SelectList(db.Empresas, "EmpresaID", "Nombre", dispositivo.EmpresaID);
        return View(dispositivo);
    }

我有下一个错误:

Error CS1061 'Device' does not contain a definition for 'GetAwaiter' and no extension method 'GetAwaiter' accepting a first argument of type 'Device' could be found (are you missing a using directive or an assembly reference?)

在“设备”中有:

using System;
using Microsoft.Azure.Devices.Common;
using Newtonsoft.Json;
using Newtonsoft.Json.Converters;

namespace Microsoft.Azure.Devices
{
    public class Device : IETagHolder
    {
        public Device();
        public Device(string id);

        [JsonProperty(PropertyName = "authentication")]
        public AuthenticationMechanism Authentication { get; set; }
        [JsonProperty(PropertyName = "cloudToDeviceMessageCount")]
        public int CloudToDeviceMessageCount { get; }
        [JsonConverter(typeof(StringEnumConverter))]
        [JsonProperty(PropertyName = "connectionState")]
        public DeviceConnectionState ConnectionState { get; }
        [JsonProperty(PropertyName = "connectionStateUpdatedTime")]
        public DateTime ConnectionStateUpdatedTime { get; }
        [JsonProperty(PropertyName = "etag")]
        public string ETag { get; set; }
        [JsonProperty(PropertyName = "generationId")]
        public string GenerationId { get; }
        [JsonProperty(PropertyName = "deviceId")]
        public string Id { get; }
        [JsonProperty(PropertyName = "lastActivityTime")]
        public DateTime LastActivityTime { get; }
        [JsonConverter(typeof(StringEnumConverter))]
        [JsonProperty(PropertyName = "status")]
        public DeviceStatus Status { get; set; }
        [JsonProperty(PropertyName = "statusReason")]
        public string StatusReason { get; set; }
        [JsonProperty(PropertyName = "statusUpdatedTime")]
        public DateTime StatusUpdatedTime { get; }
    }
}

Answer 1

您必须等待异步方法返回的任务，而不是 task.Result。使用 await 时，返回表达式的值将已经是 task.Result 属性。

因此在异步调用后删除 .Result，它应该可以正常工作。

try
{
    device =  await registryManager.AddDeviceAsync(new Device(dispositivo.Nombre));

 }
 catch (DeviceAlreadyExistsException)
 {
    device = await registryManager.GetDeviceAsync(dispositivo.Nombre);
 }