当我尝试调用Web API时，Windows Phone应用程序无法正常运行

Question

我正在开发一个简单的Windows Phone 8应用程序。
我不使用MVVM ，这非常简单。
我有一个按钮，当我按下它时，我想向数据库中添加一些数据（使用post方法）。
Web API是在asp.net制作的，并且可以正常工作，因为我使用了fiddler和控制台应用程序进行了测试。
该按钮后面的代码如下：

private void Button_Click(object sender, RoutedEventArgs e)
    {
        HttpClient client = new HttpClient();
        string baseUrl = "myWebApiLink";
        client.BaseAddress = new Uri(baseUrl);
        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

        string serviceUrl;
        serviceUrl = "api/People";

        var anEmployee = new People()
         {
             FirstName = "Windows",
             LastName = "Phone",
             Age = 8
         };
         HttpResponseMessage response;
         response = client.PostAsJsonAsync(serviceUrl, anEmployee).Result; //the problem
         if (response.IsSuccessStatusCode)
         {
             //some success messages
         }
         else
         {
             //some fail messages
         }
UriKind.Relative));
    }

在生产线上

response = client.PostAsJsonAsync(serviceUrl, anEmployee).Result;  

该应用程序只是被阻止。
它不会引发异常，它只会停留在该行上。

有任何想法吗？

先感谢您！

Answer 1

实际上，我不认为这句话说的是，您正在调用异步方法，这意味着您的代码将继续执行，并且不等待响应。 通过添加异步来更改方法签名，然后等待调用重新启动将起作用。 这是修改您的代码。

private async void Button_Click(object sender, RoutedEventArgs e)
    {
        HttpClient client = new HttpClient();
        string baseUrl = "myWebApiLink/";
        client.BaseAddress = new Uri(baseUrl);
        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

        string serviceUrl;
        serviceUrl = "api/People";

        var anEmployee = new People()
        {
            FirstName = "Windows",
            LastName = "Phone",
            Age = 8
        };

        var request = new HttpRequestMessage(HttpMethod.Post, serviceUrl);
        var requestContent = anEmployee; //this value is a string, check the format on your server

        request.Content = new StringContent(requestContent, Encoding.UTF8, "application/json");

        HttpResponseMessage response;
        response = await client.SendAsync(request); //no longer the problem

        if (response.IsSuccessStatusCode)
        {
            //some success messages
        }
        else
        {
            //some fail messages
        }
    }

Answer 2

使用异步按钮客户端并等待异步调用后...这是方法。

private async void Button_Click(object sender, RoutedEventArgs e)
{
    HttpClient client = new HttpClient();
    string baseUrl = "myWebApiLink";
    client.BaseAddress = new Uri(baseUrl);
    client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
    string serviceUrl;
    serviceUrl = "api/People";
    var anEmployee = new People()
     {
         FirstName = "Windows",
         LastName = "Phone",
         Age = 8
     };
    HttpResponseMessage response;
    response = await client.PostAsJsonAsync(serviceUrl, anEmployee).Result;
    if (response.IsSuccessStatusCode)
    {
        //some success messages
    }
    else
    {
        //some fail messages
    }
}