當我嘗試調用Web API時，Windows Phone應用程序無法正常運行

Question

我正在開發一個簡單的Windows Phone 8應用程序。
我不使用MVVM ，這非常簡單。
我有一個按鈕，當我按下它時，我想向數據庫中添加一些數據（使用post方法）。
Web API是在asp.net制作的，並且可以正常工作，因為我使用了fiddler和控制台應用程序進行了測試。
該按鈕后面的代碼如下：

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));
    }

在生產線上

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

該應用程序只是被阻止。
它不會引發異常，它只會停留在該行上。

有任何想法嗎？

先感謝您！

Answer 1

實際上，我不認為這句話說的是，您正在調用異步方法，這意味着您的代碼將繼續執行，並且不等待響應。 通過添加異步來更改方法簽名，然后等待調用重新啟動將起作用。 這是修改您的代碼。

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

使用異步按鈕客戶端並等待異步調用后...這是方法。

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
    }
}