c# HttpClient 给webapi post接口传递一个参数。传递参数的同时传递一个cookie

webapi post传递一个参数是真的坑，有多坑，可以看看这篇文章：
https://www.tnblog.net/aojiancc2/article/details/2874

当然现在说的是怎么用HttpClient来调用webapi post只有一个参数的情况

webapi如下，就是一个非常简单的post

[HttpPost]
public void Post([FromBody]string value)
{
}

开始尝试调用，肯定要避免第一个坑，键名为空

var handler = new HttpClientHandler() { AutomaticDecompression = DecompressionMethods.GZip };
HttpClient httpClient = new HttpClient(handler);
var content = new FormUrlEncodedContent(new Dictionary<string, string>()
{
    {"", "hhhh"}//键名必须为空
});
var response = httpClient.PostAsync("your address", content).Result;
//确保HTTP成功状态值
response.EnsureSuccessStatusCode();
//await异步读取最后的JSON（注意此时gzip已经被自动解压缩了，因为上面的AutomaticDecompression = DecompressionMethods.GZip）
string result = response.Content.ReadAsStringAsync().Result;

然鹅报错：StatusCode: 415, ReasonPhrase: ‘Unsupported Media Type’

按照js调用的经验，设置一个json格式在尝试一下

var handler = new HttpClientHandler() { AutomaticDecompression = DecompressionMethods.GZip };
HttpClient httpClient = new HttpClient(handler);
var content = new FormUrlEncodedContent(new Dictionary<string, string>()
{
    {"", "hhhwww"}//键名必须为空
});
//设置json格式
content.Headers.ContentType = new MediaTypeHeaderValue("application/json");
var response = httpClient.PostAsync("你的地址", content).Result;
//确保HTTP成功状态值
response.EnsureSuccessStatusCode();
//await异步读取最后的JSON（注意此时gzip已经被自动解压缩了，因为上面的AutomaticDecompression = DecompressionMethods.GZip）
string result = response.Content.ReadAsStringAsync().Result;

然鹅，和ajax调用一样报错：StatusCode: 400, ReasonPhrase: ‘Bad Request

按照ajax调用的经验，把它换成stringcontent传值把，注意三点，不能有key,而且格式设置成json,还有就是格式用json序列化一下

httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
StringContent strcontent = new StringContent(JsonConvert.SerializeObject("alal"), Encoding.UTF8, "application/json");
var result = httpClient.PostAsync("your address", strcontent).Result;

传递参数的同时传递一个cookie

HttpClient httpClient = new HttpClient();
httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
StringContent strcontent = new StringContent(JsonConvert.SerializeObject("aa"), Encoding.UTF8, "application/json");
var message = new HttpRequestMessage(HttpMethod.Post, "your address");
//设置cookie信息
message.Headers.Add("Cookie", "token=" + token);
//设置contetn
message.Content = strcontent;
//发送请求
var httpResponseHeaders = httpClient.SendAsync(message).Result;

搞定收工