你好,我似乎無法弄清楚,爲什麼我的COMBOX保持爲空:/C#UWP綁定組合框的SelectedItem
在頁面加載第一COMBOX獲取與國家(從JSON)填充,第二個組合框應填充時,國家在第一個組合框中被選中。我試圖在屬性中獲取SelectedItem(country)作爲字符串... SelectedItem的類型是ComboBoxItem?我認爲這是錯誤的地方。
的(視圖)模型,其中所述排序綁定屬性是:
public class LocalityModel : NotifyProp
{
#region properties
private static List<LocalityJSON> dataList;
public List<LocalityJSON> DataList
{
get
{
return dataList;
}
set {
dataList = value;
RaisePropertyChanged("Landen");
RaisePropertyChanged("Gewesten");
}
}
public List<string> Landen
{
get { if (DataList == null) return null; return (from s in DataList orderby s.Land select s.Land).Distinct().ToList<string>(); }
}
public string SelectedLand { get; set; }
public List<string> Gewesten {
get { if (DataList == null) return null; return (from s in DataList where s.Land.Equals(SelectedLand) select s.Gewest).Distinct().ToList<string>(); }
}
#endregion
#region ctor
public LocalityModel()
{
FillDataList();
}
#endregion
#region methodes
public async void FillDataList()
{
if (DataList == null)
{
DataList = await EVNT.Entries();
}
}
#endregion
}
的MainPage XAML(綁定):
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}" DataContext="{Binding Source={StaticResource LocalityModel}}">
...
<TextBlock x:Name="txbCountry" Style="{StaticResource InfoLabelCountry}" />
<ComboBox x:Name="cboCountry" Style="{StaticResource CountryBox}" ItemsSource="{Binding Landen}" SelectedItem="{Binding SelectedLand, Mode=TwoWay}" />
<TextBlock x:Name="txbGewest" Style="{StaticResource InfoLabelGewest}" />
<ComboBox x:Name="cboGewest" Style="{StaticResource GewestBox}" ItemsSource="{Binding Gewesten}" />
INotifyPropertyChanged的:
public class NotifyProp : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
public void RaisePropertyChanged(string propertyName)
{
if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
爲模型JSON:
public class LocalityJSON
{
public string FB_ID { get; set; }
public string Land { get; set; }
public string Gewest { get; set; }
public string City { get; set; }
}
的JSON deserialisation(對這個問題不太重要):
public class EVNT
{
public async static Task<List<LocalityJSON>> Entries()
{
using (var client = new HttpClient())
{
client.BaseAddress = new Uri(@"http://e-vnt.com/admin/core/api/");
HttpResponseMessage response = await client.GetAsync("localityApi");
if (response.IsSuccessStatusCode)
{
String s = await response.Content.ReadAsStringAsync();
List<LocalityJSON> entries = JsonConvert.DeserializeObject<List<LocalityJSON>>(s);
return entries;
}
else
return null;
}
}
}
提示:在複製粘貼代碼時,取消縮進以使最外層的hs縮進四個空格。這可以避免不必要的水平滾動。 –
我的歉意,我會在下次 –
沒有必要道歉。但你可以編輯這篇文章。 –