httpclient调用webapi发布数据不起作用

Question

我需要使用字符串参数对post方法进行简单的webapi调用.

下面是我正在尝试的代码,但是当在webapi方法上遇到断点时,接收的值是null.

StringContent stringContent = new System.Net.Http.StringContent("{ \"firstName\": \"John\" }", System.Text.Encoding.UTF8, "application/json");
HttpClient client = new HttpClient();
HttpResponseMessage response = await client.PostAsync(url.ToString(), stringContent);

和服务器端代码:

 // POST api/values
[HttpPost]
public void Post([FromBody]string value)
{
}

请帮忙...

Answer 1

如果要将json发送到Web API,最好的选择是使用模型绑定功能,并使用Class,而不是字符串.

创建一个模型

public class MyModel
{
    [JsonProperty("firstName")]
    public string FirstName { get; set; }
}

如果你不使用JsonProperty属性,你可以用小写的驼峰编写属性,就像这样

public class MyModel
{
    public string firstName { get; set; }
}

然后更改您的操作,将de参数类型更改为MyModel

[HttpPost]
public void Post([FromBody]MyModel value)
{
    //value.FirstName
}

您可以使用Visual Studio自动创建C#类,在此处查看此答案将JSON反序列化为对象C#

我做了以下测试代码

Web API控制器和视图模型

using System.Web.Http;
using Newtonsoft.Json;

namespace WebApplication3.Controllers
{
    public class ValuesController : ApiController
    {
        [HttpPost]
        public string Post([FromBody]MyModel value)
        {
            return value.FirstName.ToUpper();
        }
    }

    public class MyModel
    {
        [JsonProperty("firstName")]
        public string FirstName { get; set; }
    }
}

Console客户端应用程序

using System;
using System.Net.Http;

namespace Temp
{
    public class Program
    {
        public static void Main(string[] args)
        {
            Console.WriteLine("Enter to continue");
            Console.ReadLine();
            DoIt();
            Console.ReadLine();
        }

        private static async void DoIt()
        {
            using (var stringContent = new StringContent("{ \"firstName\": \"John\" }", System.Text.Encoding.UTF8, "application/json"))
            using (var client = new HttpClient())
            {
                try
                {
                    var response = await client.PostAsync("http://localhost:52042/api/values", stringContent);
                    var result = await response.Content.ReadAsStringAsync();
                    Console.WriteLine(result);
                }
                catch (Exception ex)
                {
                    Console.ForegroundColor = ConsoleColor.Red;
                    Console.WriteLine(ex.Message);
                    Console.ResetColor();
                }
            }
        }
    }
}

产量

Enter to continue

"JOHN"