在 web api 中传递 Dictionary<string,string> 参数

Question

我正在尝试将 Dictionary<string,string> 对象作为参数传递给我的 web api 方法，但如果我检查日志文件，它总是以 0 计数出现：

Web api 方法：

[HttpPost]
[ActionName("SendPost")]
public void SendPost([FromBody] Dictionary<string,string> values)
{
    using (var sw = new StreamWriter("F:\\PostTest.txt", true))
    {
        sw.WriteLine("Number of items in the dictionary - " + values.Count);
    }
}

调用web api的逻辑：

public HttpResponseMessage Send(string uri, string value)
{
    HttpResponseMessage responseMessage = null;

    using (var client = new HttpClient())
    {
        client.BaseAddress = new Uri(URI);
        client.DefaultRequestHeaders.Accept.Clear();
        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

        var content = new FormUrlEncodedContent
            (
                new Dictionary<string, string> { { "value", value } }
            );

        responseMessage = client.PostAsync(uri, content).Result;
    }
    return responseMessage;
}

Answer 1

问题在于您说内容类型是“application/json”，但您将其传递为FormUrlEncodedContent。您需要自己使用StringContent将内容序列化为JSON，也可以使用扩展方法HttpClientExtensions.PostAsJsonAsync为您将内容序列化为JSON：

public async Task<HttpResponseMessage> SendAsync(string uri, string value)
{
    using (var client = new HttpClient())
    {
        client.BaseAddress = new Uri(URI);
        client.DefaultRequestHeaders.Accept.Clear();
        client.DefaultRequestHeaders.Accept.Add(
                        new MediaTypeWithQualityHeaderValue("application/json"));

        return await client.PostAsJsonAsync(uri, content);
    }
}