如何在 Windows Phone 8 的 HttpClient 请求中发送 Post 正文？

Question

我已经编写了下面的代码来发送标题，发布参数。问题是我使用的是 SendAsync，因为我的请求可以是 GET 或 POST。如何将 POST Body 添加到这段代码中，以便如果有任何 post body 数据，它会被添加到我发出的请求中，并且如果它的简单 GET 或 POST 没有 body，它会以这种方式发送请求。请更新以下代码：

HttpClient client = new HttpClient();

// Add a new Request Message
HttpRequestMessage requestMessage = new HttpRequestMessage(RequestHTTPMethod, ToString());

// Add our custom headers
if (RequestHeader != null)
{
    foreach (var item in RequestHeader)
    {

        requestMessage.Headers.Add(item.Key, item.Value);

    }
}

// Add request body


// Send the request to the server
HttpResponseMessage response = await client.SendAsync(requestMessage);

// Get the response
responseString = await response.Content.ReadAsStringAsync();

Answer 1

我确实创建了一个方法：

public static StringContent GetBodyJson(params (string key, string value)[] param)
    {
        if (param.Length == 0)
            return null;

        StringBuilder builder = new StringBuilder();

        builder.Append(" { ");

        foreach((string key, string value) in param)
        {
            builder.Append(" \"" + key + "\" :"); // key
            builder.Append(" \"" + value + "\" ,"); // value
        }

        builder.Append(" } ");

        return new StringContent(builder.ToString(), Encoding.UTF8, "application/json");
    }

obs : 在HttpContent中使用StringContent，继承是StringContent -> ByteArrayContent -> HttpContent。

Answer 2

更新 2：

来自@Craig Brown：

从 .NET 5 开始，您可以这样做：
requestMessage.Content = JsonContent.Create(new { Name = "John Doe", Age = 33 });

参见JsonContent 类文档

更新 1：

哦，它可以更好（来自answer）：

requestMessage.Content = new StringContent("{\"name\":\"John Doe\",\"age\":33}", Encoding.UTF8, "application/json");

这取决于你有什么内容。您需要使用新的HttpContent 初始化您的requestMessage.Content 属性。例如：

...
// Add request body
if (isPostRequest)
{
    requestMessage.Content = new ByteArrayContent(content);
}
...

content 是您的编码内容。您还应该包含正确的 Content-type 标头。

Answer 3

我通过以下方式实现它。我想要一个通用的 MakeRequest 方法，它可以调用我的 API 并接收请求正文的内容 - 并将响应反序列化为所需的类型。我创建了一个Dictionary<string, string> 对象来存放要提交的内容，然后用它设置HttpRequestMessage Content 属性：

调用 API 的通用方法：

    private static T MakeRequest<T>(string httpMethod, string route, Dictionary<string, string> postParams = null)
    {
        using (var client = new HttpClient())
        {
            HttpRequestMessage requestMessage = new HttpRequestMessage(new HttpMethod(httpMethod), $"{_apiBaseUri}/{route}");

            if (postParams != null)
                requestMessage.Content = new FormUrlEncodedContent(postParams);   // This is where your content gets added to the request body


            HttpResponseMessage response = client.SendAsync(requestMessage).Result;

            string apiResponse = response.Content.ReadAsStringAsync().Result;
            try
            {
                // Attempt to deserialise the reponse to the desired type, otherwise throw an expetion with the response from the api.
                if (apiResponse != "")
                    return JsonConvert.DeserializeObject<T>(apiResponse);
                else
                    throw new Exception();
            }
            catch (Exception ex)
            {
                throw new Exception($"An error ocurred while calling the API. It responded with the following message: {response.StatusCode} {response.ReasonPhrase}");
            }
        }
    }

调用方法：

    public static CardInformation ValidateCard(string cardNumber, string country = "CAN")
    { 
        // Here you create your parameters to be added to the request content
        var postParams = new Dictionary<string, string> { { "cardNumber", cardNumber }, { "country", country } };
        // make a POST request to the "cards" endpoint and pass in the parameters
        return MakeRequest<CardInformation>("POST", "cards", postParams);
    }