Question

我正在尝试刷新我的WPF应用程序中的列表框，但它似乎无法正常工作。

如果我在添加值后重新加载应用程序，则会添加值。

我有一个名为＆＃39; listboxData＆＃39;：

的变量和属性

    ObservableCollection<ITimeLineDataItem> listboxData = new ObservableCollection<ITimeLineDataItem>();
    public ObservableCollection<ITimeLineDataItem> ListBoxData
    {
        get
        {
            return listboxData;
        }        
    }

我已将Listbox的值绑定到此属性：

<ListBox x:Name="ListSrc" ItemsSource="{Binding Path=ListBoxData}" dd:DragDrop.IsDragSource="True" VerticalAlignment="Stretch" HorizontalAlignment="Stretch" BorderBrush="Transparent" BorderThickness="0">

当用户添加一个值时，会调用此代码：

public void RefreshListbox()
{

        listboxData.Clear();

        foreach (podiaPublish.Marker pMarker in Global.gChapter.MarkerList)
        {
            foreach (podiaPublish.Content pContent in pMarker.ContentList)
            {

                //FOR SLIDES THAT HAVE JUST BEEN IMPORTED, THERE WILL BE NO FILES ON THE SERVER (SO NO CHECKSUMS AVAILABLE)

                if (File.Exists(Global.TempFolder + "\\" + (string.IsNullOrEmpty(pContent.AlternateMarkup) ? pContent.Markup : pContent.AlternateMarkup)))
                {
                    //KLUDGE TO RESIZE THE THUMBNAILS
                    System.IO.FileStream fs = new System.IO.FileStream(Global.TempFolder + "\\" + (string.IsNullOrEmpty(pContent.AlternateMarkup) ? pContent.Markup : pContent.AlternateMarkup), FileMode.Open, FileAccess.Read);
                    Bitmap bm = new Bitmap(fs);
                    var bitmapSource = Imaging.CreateBitmapSourceFromHBitmap(bm.GetHbitmap(),
                                                                        IntPtr.Zero,
                                                                        Int32Rect.Empty,
                                                                        BitmapSizeOptions.FromEmptyOptions()
                    );
                    bm.Dispose();
                    fs.Close();

                    if (pContent.Markup.Contains(".png"))
                    {
                        var brush = new ImageBrush(bitmapSource);

                        var lb1 = new TempDataType()
                        {
                            Name = pContent.Markup,
                            BackgroundImage = brush
                        };

                        listboxData.Add(lb1);
                    }
                }
            }
        }
    }

所以我先清除＆＃39; listboxData＆＃39;然后你可以在foreach循环中看到我重新添加新值。调试时返回正确的值。

编辑：

列表框的属性绑定在：

中

    <DataTemplate  DataType="{x:Type tt:TempDataType}">
        <Border BorderThickness="1"
                BorderBrush="Black"
                Background="{Binding BackgroundImage}"
                CornerRadius="3"
                Height="120">
            <StackPanel Orientation="Vertical">
                <Image Source="{Binding BackgroundImage}" />
                <TextBlock Text="{Binding Name}" />
            </StackPanel>
        </Border>
    </DataTemplate>

TempDataType类的结构如下：

public class TempDataType : ITimeLineDataItem, INotifyPropertyChanged
{
    public TimeSpan? StartTime { get; set; }
    public TimeSpan? EndTime { get; set; }
    public ImageBrush BackgroundImage { get; set; }
    public Boolean TimelineViewExpanded { get; set; }
    public String Name { get; set; }
}

Answer 1

我相信您正在使用MVVM模式，但如果您不使用MVVM，则无法以任何方式查看代码中的属性更改事件（INotifyPropertyChanged），然后直接使用Listbox对象在列表中添加项目：

    public ObservableCollection<ITimeLineDataItem> ListBoxData
    {
        get
        {
            return this.listboxData;
        }
        set
        {
                this.listboxData = value;
                this.RaisePropertyChanged(() => this.ListBoxData);

        }
    }

Answer 2

请参阅此代码，我已在viewmodel中实现了该接口：

class YourViewModel:INotifyPropertyChanged
{


    #region INotifyPropertyChanged Members

    public event PropertyChangedEventHandler PropertyChanged;

    //method to fire the property changed event ...
    void OnPropertyChanged(string propertyName)
    {

        var handler = PropertyChanged;

        if (handler != null)
            handler(this, new PropertyChangedEventArgs(propertyName));
    }

    //To raise the changes in property ...
    protected void RaisePropertyChanged<T>(Expression<Func<T>> propertyExpression)
    {
        var propertyName = PropertySupport.ExtractPropertyName(propertyExpression);
        this.OnPropertyChanged(propertyName);
    }

    #endregion
}

WPF C＃刷新/重新绑定列表框

2 个答案: