Question

全部，我最近遇到了一个问题，即当选定的行滚动（WPF DataGrid Column Becoming Corrupt when using Multi-Selection）时，DataGrid的视觉效果没有更新，这是使用链接答案中的方法解决的。

我在TextBlock中有一个StatusBar，我将其绑定到IsSelected属性到所需的ViewModel。我认为上述问题的解决方案也可以解决所选行数没有正确更新的事实;也就是说，当DataGrid滚动条不移动时它会更新，但是当条形图移动时，TextBlock无法更新，因为OnPropertyChanged事件未被触发。我已经检查了很多帖子，并设置IsAsync=true，这有助于使选择正确（在此更新之前它是1）。相关的XMAL是

<DataGrid Grid.Row="1" AlternatingRowBackground="Gainsboro" AlternationCount="2" 
          HorizontalAlignment="Stretch" VerticalAlignment="Stretch" 
          AutoGenerateColumns="False" RowHeaderWidth="0" IsReadOnly="True"
          CanUserAddRows="False" CanUserDeleteRows="False" SelectionMode="Extended" 
          EnableRowVirtualization="True" EnableColumnVirtualization="True" 
          ItemsSource="{Binding Cultures, NotifyOnSourceUpdated=True, UpdateSourceTrigger=PropertyChanged, IsAsync=True}" 
          dataAccess:MultiSelectItem.IsEnabled="True">
 <DataGrid.Columns>
    <DataGridTextColumn Header="Code" Binding="{Binding Code}" IsReadOnly="True"/>
    <DataGridTextColumn Header="Language" Binding="{Binding Language}" IsReadOnly="True"/>
    <DataGridTextColumn Header="LocalName" Binding="{Binding LocalName}" IsReadOnly="True"/>
 </DataGrid.Columns>
</DataGrid>

<StatusBar Grid.Row="1" Margin="0,0.4,0.4,-0.4">
    <StatusBarItem DockPanel.Dock="Left" Background="#FF007ACC" Margin="0,2,0,0">
       <TextBlock Text="{Binding TotalSelectedCultures}"  Margin="5,0,0,0" Foreground="White"/>
    </StatusBarItem>
</StatusBar>

此链接的视图模型是

public class CultureDataViewModel : ViewModelBase
{
    public enum FilterType
    {
      AllCultures,
      NeutralCultures,
      SpecificCultures
    };
    public FilterType SelectedFilterType { get; private set; }
    public ICollectionView CulturesView { get; private set; }
    public MultiSelectCollectionView<CultureViewModel> Cultures { get; private set; }

    public CultureDataViewModel()
    {
        SelectedFilterType = FilterType.AllCultures;
        LoadCultures();
    }

    void OnCultureViewModelPropertyChanged(object sender, PropertyChangedEventArgs e)
    {
        string IsSelected = "IsSelected";
        (sender as CultureViewModel).VerifyPropertyName(IsSelected);
        if (e.PropertyName == IsSelected)
            this.OnPropertyChanged("TotalSelectedCultures");
    }

    void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
    {
        if (e.NewItems != null && e.NewItems.Count != 0)
            foreach (CultureViewModel cultVm in e.NewItems)
                cultVm.PropertyChanged += this.OnCultureViewModelPropertyChanged;

        if (e.OldItems != null && e.OldItems.Count != 0)
            foreach (CultureViewModel cultVm in e.OldItems)
                cultVm.PropertyChanged -= this.OnCultureViewModelPropertyChanged;
    }

    /// <summary>
    /// Load the avalible cultures depending on filter selection
    /// </summary>
    public void LoadCultures()
    {
        // Get data...
    }

    /// <summary>
    /// Hold the current total selected cultures to add to the resource 
    /// data set.
    /// </summary>
    public string TotalSelectedCultures
    {
        get
        {
            int selectedCultures = this.Cultures.SelectedItems.Count;
            return String.Format("{0:n0} of {1:n0} cultures selected",
                                        selectedCultures,
                                        Cultures.Count);
        }
    }
}

{p> TotalSelectedCultures在DataGrid滚动时停止更新，如何停止此操作并允许行数显示，即使在这种情况下也是如此？

感谢您的时间。

Answer 1

你能简单地附加到LoadCultures（）里面的SelectedItems.CollectionChanged事件吗？

Cultures.SelectedItems.CollectionChanged += SelectedItems_CollectionChanged;

void SelectedItems_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
    this.RaisePropertyChanged("TotalSelectedCultures");
}

将选定的RowCount绑定到TextBlock，而不是在DataGrid Scroll之后触发OnPropertyChanged

1 个答案: