我将一些代码从一个网站中分离出来,并且在复制相关特定页面后面的代码后,我在PostAsJsonAsync()代码行上发生错误：
HttpResponseMessage response = await client.PostAsJsonAsync("api/...",user);
using System;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Net.Mail;
using System.Threading.Tasks;
//...
using (var client = new HttpClient())
{
client.BaseAddress = new Uri("WebServiceAddress");
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
HttpResponseMessage response = await client.PostAsJsonAsync("api/...",user);
if (response.IsSuccessStatusCode)
{
const string result = "Thank you for your submission.";
return result;
}
//...
}
我得到的错误说
Error 4 'System.Net.Http.HttpClient' does not contain a definition for 'PostAsJsonAsync' and no extension method 'PostAsJsonAsync' accepting a first argument of type 'System.Net.Http.HttpClient' could be found (are you missing a using directive or an assembly reference?)
即使它在前一个项目中工作,并从该项目中直接复制.我忘了添加东西吗？
我感谢任何有关此事的帮助.
