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我是新来的异步和等待编程风格。我如何解决以下问题:异步等待执行windows phone 8
我打电话给下面的代码。这里的问题在于,第一行正在等待填充categoriesvm.Categorieslist
的哪个需要,但它没有,但第二行被调用。 (我认为这是await的默认行为)
如何确保只有在第一行填充了categoriesvm.Categorieslist
时才调用第二行?
protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
{
categoriesvm.GetCategories();
BookCategories.DataContext = from vm in categoriesvm.Categorieslist select vm;
}
在当我执行它低于其中Categorieslist
是我上述访问列表的第一行之上的代码。
public async void GetCategories()
{
Categorieslist = new ObservableCollection<Categories>(await PhoneClient.GetDefaultCategories());
}
的phoneclient
低于
public class PhoneClient
{
private static readonly HttpClient client;
public static Uri ServerBaseUri
{
get { return new Uri("http://169.254.80.80:30134/api/"); }
}
static PhoneClient()
{
client =new HttpClient();
client.MaxResponseContentBufferSize = 256000;
client.DefaultRequestHeaders.Add("user-agent", "Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; WOW64; Trident/6.0)");
}
public async static Task<List<Categories>> GetDefaultCategories()
{
HttpResponseMessage getresponse = await client.GetAsync(ServerBaseUri + "Categoryss");
string json = await getresponse.Content.ReadAsStringAsync();
json = json.Replace("<br>", Environment.NewLine);
var categories = JsonConvert.DeserializeObject<List<Categories>>(json);
return categories.ToList();
}
}