Return list instead of an item Webservice Phone 8.1 UAP

问题

Ok So I have been asked to create a new question I have got my json now returning fine and into my class of city fine and dandy now using the following structure. But my quesiton is how do i return it as a List so that can be bound to a listview for example my get call is as follows

public async Task<City> GetCityListAsync()
    {

        var tcs = new TaskCompletionSource<City>();
        string jsonresult = await WCFRESTServiceCall("GET", "cinema_city");

        var list = await Task.Run(() => jsonresult.Deserialize<City>());
        tcs.SetResult(list);
        // for testing to show json being returned
        var dialog = new MessageDialog(jsonresult);
        await dialog.ShowAsync();

        return await tcs.Task;
 }

This is where I am calling my method

private async void citys_loaded(object sender, RoutedEventArgs e)
{
        popcornpk_Dal popcorn_dal = new popcornpk_Dal();

        City _mycitys = await popcorn_dal.GetCityListAsync();

        var listView = (ListView)sender;

       listView.ItemsSource = _mycitys.ToString();
 }

So My main quesiton is how do i return a list of objects to my listview cause when i process i am just getting popcorn.dal.city in the xaml

XAML Layout

<Pivot x:Name="myPivot">
        <PivotItem x:Name="pivot_item1" Header="by city" Margin="10,-76,28,-20.833">
            <StackPanel Height="505">
                <Grid Margin="0,0,0,118" Height="514"  >
                    <ListView  x:Name="listByCity" ItemsSource="{Binding}" Loaded="citys_loaded">

                        <DataTemplate>
                            <TextBlock x:Name="City" FontSize="14" Text="{Binding timing_title}"></TextBlock>

                        </DataTemplate>

                    </ListView>

                </Grid>
            </StackPanel>
        </PivotItem>

Class for completness of quesiton

    public class City
    {
        public string id { get; set; }
        public string timing_title { get; set; }
        }
    public class Citys
    {
        public List<City> city { get; set; }
     }

My Helper Function here

public static T Deserialize<T>(this string SerializedJSONString)
{
        var stuff = JsonConvert.DeserializeObject<T>(SerializedJSONString);
        return stuff;
}

Edit to show webserivce call which is php mysql based i dont need change that side just .net side into a list

   private async Task<string> WCFRESTServiceCall(string methodRequestType, string methodName, string bodyParam = "")
    {
        string ServiceURI = "/launchwebservice/index.php/webservice/" + methodName;
        HttpClient httpClient = new HttpClient();
        HttpRequestMessage request = new HttpRequestMessage(methodRequestType == "GET" ? HttpMethod.Get : HttpMethod.Post, ServiceURI);
        if (!string.IsNullOrEmpty(bodyParam))
        {
            request.Content = new StringContent(bodyParam, Encoding.UTF8, "application/json");
        }
        HttpResponseMessage response = await httpClient.SendAsync(request);
        string jsongString = await response.Content.ReadAsStringAsync();
        return jsongString;
    }
}

Also when calling a webservice what is the best method for error checking here I no i could use try catch and put a message say services could not be contacted but are their spefic messages I should be trapping for.

cinema_city method returns this json

{"city":[{"id":"5521","timing_title":"Lahore"},{"id":"5517","timing_title":"Karachi"},{"id":"5538","timing_title":"Islamabad"},{"id":"5535","timing_title":"Rawalpindi"},{"id":"5518","timing_title":"Hyderabad"},{"id":"5512","timing_title":"Faisalabad"},{"id":"8028","timing_title":"Gujranwala"},{"id":"8027","timing_title":"Gujrat"}]}

回答1:

You are asking the same question again. If you have this json:

 {"city":[{"id":"5521","timing_title":"Lahore"},  
          {"id":"5517","timing_title":"Karachi"},
          {"id":"5538","timing_title":"Islamabad"},
          {"id":"5535","timing_title":"Rawalpindi"},
          {"id":"5518","timing_title":"Hyderabad"},
          {"id":"5512","timing_title":"Faisalabad"},
          {"id":"8028","timing_title":"Gujranwala"},
          {"id":"8027","timing_title":"Gujrat"}]}

You need to deserialize it to your Citys class ( btw rename it to Cities maybe? )

So your code going to be:

  public async Task<Citys> GetCityListAsync()
  {

        var tcs = new TaskCompletionSource<City>();
        string jsonresult = await WCFRESTServiceCall("GET", "cinema_city");

        var list = await Task.Run(() => jsonresult.Deserialize<Citys>());
        tcs.SetResult(list);
        // for testing to show json being returned
        var dialog = new MessageDialog(jsonresult);
        await dialog.ShowAsync();

        return await tcs.Task;
 }

or in case you want to return just List and not the wrapper:

 public async Task<List<City>> GetCityListAsync()
    {

        var tcs = new TaskCompletionSource<List<City>>();
        string jsonresult = await WCFRESTServiceCall("GET", "cinema_city");

        var list = await Task.Run(() => jsonresult.Deserialize<Citys>());
        tcs.SetResult(list.city);
        // for testing to show json being returned
        var dialog = new MessageDialog(jsonresult);
        await dialog.ShowAsync();

        return await tcs.Task;
 }

Also I'm not sure why you wrote code this way. json.net async mehods are just wrappers around sync methods. so I'd simplify your code to:

 public async Task<Citys> GetCityListAsync(){ 
    var json = await WCFRESTServiceCall("GET", "cinema_city");
    return json.Deserialize(Citys);
 }

来源：https://stackoverflow.com/questions/31952133/return-list-instead-of-an-item-webservice-phone-8-1-uap