Question

我使用jsontocsharp在线转换器转换了两个api扩展。通过第一个API，类可用于通过按钮单击搜索特定书籍。在文本框中输入输入后，将显示项目列表。当用户点击书籍时，它将使用下载按钮导航到其他页面。第二个api课程显示了这本书的细节。

我可以成功显示搜索项目并在下一页显示。但是如何从类中使用此下载属性并将其链接到所选书籍。因此，当用户点击下载选项时，它应该导航到Web浏览器并应下载相应的文件。

我正在使用它 - 电子书api。请参阅此链接以获取有关api。API link here

的详细信息

private async void  search_btn_Click(object sender, RoutedEventArgs e)
{
    try
    {
        using (HttpClient client = new HttpClient())
        {
            pgbar.Visibility = Visibility.Visible;

            var uri = "http://it-ebooks-api.info/v1/search/{0}";

            client.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));

            HttpResponseMessage response = await client.GetAsync(String.Format(uri, tb1.Text));
            if (response.IsSuccessStatusCode)
            {
                var data = response.Content.ReadAsStringAsync();
                var listdata = JsonConvert.DeserializeObject<RootObject>(data.Result);

                if (listdata != null && listdata.Books != null && listdata.Books.Count > 0)
                lv1.ItemsSource = listdata.Books;
            }

我需要使用其他API来下载所选书籍。

private async void download_btn_Click(object sender, RoutedEventArgs e)
{
    using (HttpClient client = new HttpClient())
    {
        var uri = "http://it-ebooks-api.info/v1/book{}";

       //Here I should implement some code to convert from json to simple download url
        await Launcher.LaunchUriAsync(new Uri(uri));
    }

[！[在此输入图片说明] [4]] [4] 我应该在下一页显示标题和说明。所以我在新页面中绑定了listview控件。我还应该下载所选书籍的书

我得到了以下异常 [！[在此处输入图像说明] [5]] [5]

Answer 1

使用listview SelectedIndexChanged事件处理程序来了解所选项目，然后将每个项目转换为Book对象。由于您将列表“Books”分配给列表视图，因此您可以提取单个“Book”对象。请参阅代码中的注释。

private long bookid;
protected override void OnNavigatedTo(NavigationEventArgs e)
{
    dynamic bookDetails = e.Parameter;
    bookid = bookDetails.ID;
}

    private async void download_btn_Click(object sender, RoutedEventArgs e)
{
    using (HttpClient client = new HttpClient())
    {
        var id = bookid;

        var uri = "http://it-ebooks-api.info/v1/book/"+id;

       //Here I should implement some code to convert from json to simple download url
        await Launcher.LaunchUriAsync(new Uri(uri));

    }

Answer 2

我假设您将图书ID从搜索列表页面传递到图书详细信息页面

     //Class for book details

    public class BookDetails
    {
      private string Error {get; set;}
      private string Time {get; set;}
      private string ID {get; set;}
      private string Title {get; set;}
      private string SubTitle {get; set;}
      private string Description {get; set;}
      private string Author {get; set;}
      private string ISBN {get; set;}
      private string Year {get; set;}
      private string Page {get; set;}
      private string Publisher {get; set;}
      private string Image {get; set;}
      private string Download {get; set;}
    }

    private async void download_btn_Click(object sender, RoutedEventArgs e)
    {
        string downloadbookurl=string.empty;

       //Download the book detail using API http://it-ebooks-api.info/v1/book/2279690981
         string result=GetResult("http://it-ebooks-api.info/v1/book{book_isbn}")
       //Deserialise the json data
         BookDetails bookDetails= JsonConvert.DeserializeObject<BookDetails >(result);
         if(bookDetails!=null)
                downloadbookurl=bookDetails.Download ;

         }
          //Launch the webview
                 await Launcher.LaunchUriAsync(new Uri(downloadbookurl));
    }

    private async string GetResult(string url)
    {
         string response=string.empty;
         using (HttpClient client = new HttpClient())
         {
           client.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));
           HttpResponseMessage response = await client.GetAsync(String.Format(uri, tb1.Text));
           if (response.IsSuccessStatusCode)
           {
             var data = response.Content.ReadAsStringAsync();
             response=data.Result.ToString();
            }
         } 
    }

如何使用Json从Web API传递URL？

2 个答案: