C# API请求中的无效返回

此处创建了API请求的客户端和通用方法：

public class Client : IDisposable
{
    private HttpClient _client;

    private void CreateClient()
    {
        _client = new HttpClient(); 
        _client.DefaultRequestHeaders.Accept.Clear();
        _client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
        _client.DefaultRequestHeaders.Add("KEY", token);
    }


    public void Dispose() => _client?.Dispose();

    public enum Method { GET, POST, PUT, DELETE }

    public HttpResponseMessage Request(string url, Method method, object data, HttpContent request)
    {
        if (data != null)
            request = new StringContent(Serialize(data), Encoding.UTF8, "application/json");

        switch (method)
        {
            case Method.POST: return _client.PostAsync(url, request).Result;
            case Method.PUT: return _client.PutAsync(url, request).Result;
            case Method.DELETE: return _client.DeleteAsync(url).Result;
            default: return _client.GetAsync(url).Result;
        }
    }

    public Task<HttpResponseMessage> RequestAsync(string url, Method method, object data, HttpContent request)
    {
        if (data != null)
            request = new StringContent(Serialize(data), Encoding.UTF8, "application/json");

        switch (method)
        {
            case Method.GET: return _client.GetAsync(url);
            case Method.POST: return _client.PostAsync(url, request);
            case Method.PUT: return _client.PutAsync(url, request);
            case Method.DELETE: return _client.DeleteAsync(url);
            default: return _client.GetAsync(url);
        }
    }

    public string Post(string url, object data) =>
        Request(url, Method.POST, data, null).Content.ReadAsStringAsync().Result;

    public Task<HttpResponseMessage> PostAsync(string url, object data) =>
        RequestAsync(url, Method.POST, data, null);

    //UTILS

    private static string Serialize(object data) =>
        data == null
            ? string.Empty
            : JsonConvert.SerializeObject(data, new JsonSerializerSettings { NullValueHandling = NullValueHandling.Ignore });
}

请求需要基于几个模型装载，这些模型可以具有这种结构，我正试图以一种简单的方式生成它，如下所示：

    public async Task Test()
    {
        var transaction = new Transaction
        {
            PaymentMethod = new PaymentMethod { Code = "1" },
            Application = "Test",
            Vendor = "Name",
            Customer = new Customer
            {
                //Customer details...
            },
            Products = new List<TransactionProduct>
            {
                //Products...
            }
        };

        var teste = Checkout.Credit(transaction);
        Console.WriteLine(teste);
    }

public async Task<HttpResponseMessage> PostAsync(string url, object data)
{
  var result = await Request(url, Method.POST, data, null);
  return await result.Content.ReadAsStringAsync();
}

我已尝试添加

等待

进行

结帐。信用

呼叫，但我得到：

CS0815  Test C# Cannot assign void to an implicitly-typed variable

---

用一个简单的HttpClient请求进行单元测试非常有效，但我无法确定我的项目结构上的问题，因此非常感谢任何帮助

Task

是没有返回值的

async

方法的返回类型

或者，换句话说，

async

将

T

值包装到

Task

（或者

void

返回到

Task

），然后

等待

将这些值展开。由于

Credit

返回

Task

，表达式

Checkout.Credit（transaction）

的类型为

Task

，表达式

等待签出。Credit（transaction）

的类型为

void

。您不能将

void

分配给

var teste

；这就是编译器错误所说的

要解决此问题，请指定

async

方法的返回类型。特别是：

public static async Task<HttpResponseMessage> Credit(object data) => 
    await client.PostAsync(url, data);

---

这就是为什么我会把人们引导到你的任务岗位上…干得好，先生

public static async Task<HttpResponseMessage> Credit(object data) => 
    await client.PostAsync(url, data);

public string Post(string url, object data) => ...;
public Task<HttpResponseMessage> PostAsync(string url, object data) => ...;

public async Task<HttpResponseMessage> PostAsync(string url, object data)
{
  var result = await Request(url, Method.POST, data, null);
  return await result.Content.ReadAsStringAsync();
}