我正在尝试将我的集合绑定到LLS,但是我收到了InvalidCastException。如果我使用ListBox而不是LLS - 所有绑定工作正常和良好。这是我的收藏:
public class Friend : INotifyPropertyChanged
{
private string name;
public string Name { get { return name; } set { name = value; OnPropertyChanged("Name"); } }
private string image;
public string Image { get { return image; } set { image = value; OnPropertyChanged("Image"); } }
private string sourseId;
public string SourseId { get { return sourseId; } set { sourseId = value; OnPropertyChanged("SourseId"); } }
private string online_image;
public string Online_Image { get { return online_image; } set { online_image = value; if (online_image == "1") online_image = @"/icons/appbar.power.png"; OnPropertyChanged("Online_Image"); } }
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string info)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(info));
}
}
public Friend() { }
}
public class FriendList : ObservableCollection<Friend>
{
public FriendList()
: base()
{
}
}
以下是我将其绑定到LLS的方式:
XDocument xml = XDocument.Load(e.Result);
// MessageBox.Show(xml.ToString());
var users = from c in xml.Descendants("user")
select c;
foreach (var user in users)
{
Friend fr = new Friend();
fr.SourseId = (string)user.Element("uid").Value;
fr.Image = (string)user.Element("photo_medium").Value;
fr.Name = (string)user.Element("first_name").Value + " " + (string)user.Element("last_name").Value;
fr.Online_Image = (string)user.Element("online").Value;
if (fr.Online_Image == "1") fr.Online_Image = @"/icons/appbar.power.png";
FriendList.Add(fr);
}
this.AllFriendsList.ItemsSource = FriendList;
和public FriendList FriendList = new FriendList();
就在页面ctor下面。我做错了什么?字符串this.AllFriendsList.ItemsSource = FriendList;
这是我的xaml:
<toolkit:LongListSelector Name="AllFriendsList" ItemsSource="{Binding FriendList}">
<toolkit:LongListSelector.ItemTemplate>
<DataTemplate>
<Grid Height="75" Width="460" Margin="0,10,10,0">
<Line Style="{StaticResource Line1}" ></Line>
<Line Style="{StaticResource Line2}" ></Line>
<TextBlock Margin="75,15,40,0" FontSize="30" Name="Name" Text="{Binding Name}" Tap="GetUserInfo" />
<Image HorizontalAlignment="Left" Width="75" Name="Photo" >
<Image.Source>
<BitmapImage UriSource="{Binding Image}" CreateOptions="BackgroundCreation" />
</Image.Source>
</Image>
<Image HorizontalAlignment="Right" Name="IsOnline" Margin="0,0,0,0" Width="60" Height="60" Source="{Binding Online_Image}" />
</Grid>
</DataTemplate>
</toolkit:LongListSelector.ItemTemplate>
</toolkit:LongListSelector>
UPD:如果我使用this示例中的组,并将我的列表分组为
var FriendsGroup = from fr in FriendList
group fr by fr.Online_Image into c
orderby c.Key
select new Group<Friend>(c.Key, c);
AllFriendsList.ItemsSource = FriendsGroup;
它工作正常。如果我理解正确 - LLS等待分组来源。
答案 0 :(得分:1)
我通过将IsFlat更改为True来解决同样的问题。
<toolkit:LongListSelector Name="AllFriendsList" ItemsSource="{Binding FriendList}" IsFlat="True">
答案 1 :(得分:0)
您绑定了两次AllFiendsList。第一次通过xaml这里
<toolkit:LongListSelector Name="AllFriendsList" ItemsSource="{Binding FriendList}">
第二次通过代码。这可能会导致异常。