调用使用PostAsync，HttpClient的＆放从C＃的Metro UI客户MVC4的WebAPI的方法; JSON [英] Calling MVC4 WebAPI methods from C# Metro UI Client using PostAsync, HttpClient & Json

问题描述

我创建使用MVC4新的WebAPI特征的方法，并让它在Azure上运行。该方法需要您发布，它由一个用户名和密码财产的简单LoginModel对象。是的，我计划进一步保证这一次我突破这个速度碰撞:-)的方法，然后用JSON格式的对象进行响应：

I've created a method using the new WebAPI features in MVC4 and have it running on Azure. The method requires that you post a simple LoginModel object that consists of a Username and Password property. Yes, I plan on securing this further once I get past this speed bump :-) The method then responds with an object in Json format:

我可以成功调用使用招这个方法，只要我有的内容类型：应用程序/ JSON的请求头。它返回200，我可以进入提琴手检查并查看JSON响应对象就好了：

I can successfully call this method using Fiddler, provided that I include "Content-Type: application/json" in the Request Headers. It returns with 200 and I can go into the Fiddler Inspector and view the Json response object just fine:

不过，我有打电话使用C＃/ XAML在Windows8的一个MetroUI应用此方法同样的问题。我开始玩弄HttpClient的，并在C＃和无论我如何格式化我的帖子调用（甚至明确地调用出来的时候，我想的Content-Type为应用程序/ JSON）提琴手与500错误返回新的异步概念并指出尝试使用内容类型是：text / html的。我beleive这是问题的根源：

I am however having problems calling this same method from a MetroUI app in Windows8 using C#/XAML. I began playing around with the HttpClient and the new Async concepts in C# and no matter how I formatted my Post calls (even when explicitly calling out that I want the Content-Type to be "application/json") Fiddler returns with a 500 error and states that the attempt was using Content-Type:"text/html". I beleive this to be the root of the problem:

我要张贴这种方法并取回JSON对象已经尝试了一切可以想象的，这是我最近一次尝试：

I have tried everything conceivable in order to post to this method and get back the Json object, here is my most recent attempt:

HttpClient client = new HttpClient();
        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
        HttpContent content = new StringContent(@"{ ""Username"": """ + Username.Text + @", ""Password"": """ + Password.Text + @"""}");

        client.PostAsync("http://myapi.com/authentication", content).ContinueWith(result =>
        {
            var response = result.Result;

            response.EnsureSuccessStatusCode();
        });

这导致500错误与内容类型设置为text / html的

This results in a 500 error with Content-Type set to "text/html"

下面是另一个企图也失败：

Here was another attempt which also failed:

HttpClient httpClient = new HttpClient();
HttpResponseMessage response = await httpClient.PostAsync("http://myapi.com/authentication", new StringContent(@"{ ""Username"": """ + Username.Text + @", ""Password"": """ + Password.Text + @"""}", Encoding.UTF8, "application/json"));
string statusCode = response.StatusCode.ToString();

任何人都可以点我在正确的方向？

Can anyone point me in the right direction?

刚试过以下code感谢Nemesv的建议是：

Just tried the following code thanks to the advice of Nemesv:

HttpClient httpClient = new HttpClient();
        HttpContent content = new StringContent(@"{ ""Username"": """ + Username.Text + @", ""Password"": """ + Password.Text + @"""}");
        content.Headers.ContentType = new MediaTypeHeaderValue("application/json");


        HttpResponseMessage response = await httpClient.PostAsync("http://webapi.com/authentication", content);

        string statusCode = response.StatusCode.ToString();
        response.EnsureSuccessStatusCode();

现在显示在我的请求头应用/ JSON，但仍显示在Web会话text / html的

It now shows "application/json" in my request header, but still shows "text/html" in the Web Session:

推荐答案

试试这个设置 Headers.ContentType ：

HttpClient httpClient = new HttpClient();
HttpContent content = new StringContent(@"{ ""Username"": """ + "etc." + @"""}");
content.Headers.ContentType = new MediaTypeHeaderValue("application/json");
HttpResponseMessage response = 
    await httpClient.PostAsync("http://myapi.com/authentication", content);
string statusCode = response.StatusCode.ToString();

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