刷新INotifyPropertyChanged上的值转换器

我知道这里有一些类似的话题，但我无法从他们那里得到任何答案。我必须在我的Windows Phone 7应用程序中将网格的背景更新为图像或颜色。我使用我的值转换器来完成此操作，它工作得很好，但我必须重新加载集合，以便更新颜色或图像。

<Grid Background="{Binding Converter={StaticResource ImageConverter}}" Width="125" Height="125" Margin="6">

转换器接收对象，然后从中获取颜色和图像，这是转换器

public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            People myC = value as People;
            string myImage = myC.Image;
            object result = myC.TileColor;
            if (myImage != null)
            {
                BitmapImage bi = new BitmapImage();
                bi.CreateOptions = BitmapCreateOptions.BackgroundCreation;
                ImageBrush imageBrush = new ImageBrush();
                using (IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication())
                {
                    if (myIsolatedStorage.FileExists(myImage))
                    {
                        using (
                            IsolatedStorageFileStream fileStream = myIsolatedStorage.OpenFile(myImage, FileMode.Open,
                                                                                              FileAccess.Read))
                        {
                            bi.SetSource(fileStream);
                            imageBrush.ImageSource = bi;
                        }
                    }
                    else
                    {
                        return result;
                    }
                }
                return imageBrush;
            }
            else
            {
                return result;
            }
    }

我需要以某种方式更新/刷新网格标签或值转换器，以便它可以显示最新的更改!

编辑

添加更多代码

模型:

  [Table]
    public class People : INotifyPropertyChanged, INotifyPropertyChanging
    {

        private int _peopleId;
        [Column(IsPrimaryKey = true, IsDbGenerated = true, DbType = "INT NOT NULL Identity", CanBeNull = false, AutoSync = AutoSync.OnInsert)]
        public int PeopleId
        {
            get { return _peopleId; }
            set
            {
                if (_peopleId != value)
                {
                    NotifyPropertyChanging("PeopleId");
                    _peopleId = value;
                    NotifyPropertyChanged("PeopleId");
                }
            }
        }
        private string _peopleName;
        [Column]
        public string PeopleName
        {
            get { return _peopleName; }
            set
            {
                if (_peopleName != value)
                {
                    NotifyPropertyChanging("PeopleName");
                    _peopleName = value;
                    NotifyPropertyChanged("PeopleName");
                }
            }
        }


        private string _tileColor;
        [Column]
        public string TileColor
        {
            get { return _tileColor; }
            set
            {
                if (_tileColor != value)
                {
                    NotifyPropertyChanging("TileColor");
                    _tileColor = value;
                    NotifyPropertyChanged("TileColor");
                }
            }
        }

        private string _image;
        [Column]
        public string Image
        {
            get { return _image; }
            set
            {
                if (_image != value)
                {
                    NotifyPropertyChanging("Image");
                    _image = value;
                    NotifyPropertyChanged("Image");
                }
            }
        }

        [Column]
        internal int _groupId;
        private EntityRef<Groups> _group;
        [Association(Storage = "_group", ThisKey = "_groupId", OtherKey = "Id", IsForeignKey = true)]
        public Groups Group
        {
            get { return _group.Entity; }
            set
            {
                NotifyPropertyChanging("Group");
                _group.Entity = value;
                if (value != null)
                {
                    _groupId = value.Id;
                }
                NotifyPropertyChanging("Group");
            }
        }

        [Column(IsVersion = true)]
        private Binary _version;
        #region INotifyPropertyChanged Members
        public event PropertyChangedEventHandler PropertyChanged;
        private void NotifyPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
        #endregion
        #region INotifyPropertyChanging Members
        public event PropertyChangingEventHandler PropertyChanging;
        private void NotifyPropertyChanging(string propertyName)
        {
            if (PropertyChanging != null)
            {
                PropertyChanging(this, new PropertyChangingEventArgs(propertyName));
            }
        }
        #endregion
    }

ViewModel:

public class PeopleViewModel : INotifyPropertyChanged
{
    private PeopleDataContext PeopleDB;
    // Class constructor, create the data context object.
    public PeopleViewModel(string PeopleDBConnectionString)
    {
        PeopleDB = new PeopleDataContext(PeopleDBConnectionString);
    }

    private ObservableCollection<People> _allPeople;
    public ObservableCollection<People> AllPeople
    {
        get { return _allPeople; }
        set
        {
            _allPeople = value;
            NotifyPropertyChanged("AllPeople");
        }
    }
    public ObservableCollection<People> LoadPeople(int gid)
    {
        var PeopleInDB = from People in PeopleDB.People
                           where People._groupId == gid
                           select People;

        AllPeople = new ObservableCollection<People>(PeopleInDB);
        return AllPeople;
    }

    public void updatePeople(int cid, string cname, string image, string tilecol)
    {
        People getc = PeopleDB.People.Single(c => c.PeopleId == cid);
        getc.PeopleName = cname;
        getc.Image = image;
        getc.TileColor = tilecol;
        PeopleDB.SubmitChanges();
    }
    #region INotifyPropertyChanged Members
    public event PropertyChangedEventHandler PropertyChanged;
    public void NotifyPropertyChanged(string propertyName)
    {
                if (PropertyChanged != null)
                {
                    PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
                }
    }
    #endregion
}

应用程序页面

    <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
        <ListBox Margin="0,8,0,0"  x:Name="Peoplelist" HorizontalAlignment="Center"  BorderThickness="4" ItemsSource="{Binding AllPeople}">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <Grid Background="{Binding Converter={StaticResource ImageConverter}}" Width="125" Height="125" Margin="6">
                        <TextBlock Name="name" Text="{Binding PeopleName}" VerticalAlignment="Center" HorizontalAlignment="Center" TextAlignment="Center" TextWrapping="Wrap"/>
                    </Grid>
                </DataTemplate>
            </ListBox.ItemTemplate>
            <ListBox.ItemsPanel>
                <ItemsPanelTemplate>
                    <toolkit:WrapPanel/>
                </ItemsPanelTemplate>
            </ListBox.ItemsPanel>
        </ListBox>
    </Grid>

应用程序页面代码

public partial class PeopleList : PhoneApplicationPage
{
    private int gid;
    private bool firstRun;
    public PeopleList()
    {
        InitializeComponent();
        firstRun = true;
        this.DataContext = App.ViewModel;
    }
    protected override void OnNavigatedTo(NavigationEventArgs e)
    {
        gid = int.Parse(NavigationContext.QueryString["Id"]);
        if (firstRun)
        {
            App.ViewModel.LoadPeople(gid);
            firstRun = false;
        }

    }
 }