C# Can'；t将字符串转换为system.Net.HttpContent

在这里，我试图从服务中获取数据：

public async Task<IHttpActionResult> ValidateSesion()
{
    var values = new Dictionary<string, string>{
        { "productId", "1" },
        { "productKey", "Abc6666" },
        { "userName", "OPPO" },
    };
    var json = JsonConvert.SerializeObject(values, Formatting.Indented);
    // var content = new FormUrlEncodedContent(json);
    client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
    var response = await client.PostAsync("http://172.116.12.172:8014/iadmin/validate", json);
    var responseString = await response.Content.ReadAsStringAsync();
    return Ok(responseString);
}

---

更改您的返回声明，如

return Content(responseString);

---

您不能发布原始字符串，必须将其包装在StringContent中：

newstringcontent（json）

这应该可以做到：

public async Task<IHttpActionResult> ValidateSesion()
{
    var values = new Dictionary<string, string>{
      { "productId", "1" },
      { "productKey", "Abc6666" },
      { "userName", "OPPO" },
    };

    var json = JsonConvert.SerializeObject(values, Formatting.Indented);

    var stringContent = new StringContent(json);

    client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

    var response = await client.PostAsync("http://172.116.12.172:8014/iadmin/validate", stringContent);

    var responseString = await response.Content.ReadAsStringAsync();

    return Ok(responseString);
}

public异步任务ValidateSesion（）
{
var值=新字典{
{“productId”，“1”}，
{“productKey”，“Abc6666”}，
{“用户名”，“OPPO”}，
};
var json=JsonConvert.serialized对象（值、格式、缩进）；
var stringContent=新的stringContent（json）；
client.DefaultRequestHeaders.Accept.Add（新的MediaTypeWithQualityHeaderValue（“应用程序/json”）；
var response=wait client.PostAsync（“http://172.116.12.172:8014/iadmin/validate",内容),；
var responseString=await response.Content.ReadAsStringAsync（）；
返回Ok（responseString）；
}
您能否提供错误的完整跟踪信息？这可以帮助我们确定错误发生的确切位置…PostAsync方法都不接受字符串。尝试传递字符串会引发编译错误。
public async Task<IHttpActionResult> ValidateSesion()
{
    var values = new Dictionary<string, string>{
      { "productId", "1" },
      { "productKey", "Abc6666" },
      { "userName", "OPPO" },
    };

    var json = JsonConvert.SerializeObject(values, Formatting.Indented);

    var stringContent = new StringContent(json);

    client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

    var response = await client.PostAsync("http://172.116.12.172:8014/iadmin/validate", stringContent);

    var responseString = await response.Content.ReadAsStringAsync();

    return Ok(responseString);
}