Question

我已将一个Observable Collection绑定到我的MVVM-light VM中的infragistics的xamDataGrid。在UI中我有我的网格和一个按钮，当我点击按钮时，我想执行一个更新信息的操作。此操作需要一段时间，我希望数据按GUI上显示的顺序更新。但是，Observable集合未排序，而是始终在未排序列表上更新。有没有办法在我的VM中获取排序列表？

VM：

 public class SystemInformation : ViewModelBase
 {
    private ObservableCollection<Site> _activeSites;

    private RelayCommand _updateAllCommand;

    /// <summary>
    /// Initializes a new instance of the SystemInformation class.
    /// </summary>
    public SystemInformation() : base()
    {
        ActiveSites = new ObservableCollection<Site>();
    }


    public ObservableCollection<Site> ActiveSites
    {
        get
        {
            return _activeSites;
        }
        set
        {
            Set("ActiveSites", ref _activeSites, value);
        }
    }

    public RelayCommand UpdateAllCommand
    {
        get
        {
            return _updateAllCommand
              ?? (_updateAllCommand= new RelayCommand(
                () =>
                {
                        try
                        {
                            foreach (var site in ActiveSites)
                            {
                             // Update data
                            }
                        }
                        catch (Exception ex)
                        {
                           //Exception handling
                        }
                    });
                }
             ));
        }
    }
}

}

查看：

<Grid>
    <Grid.RowDefinitions>
        <RowDefinition Height="5"/>
        <RowDefinition Height="*"/>
        <RowDefinition Height="5"/>
        <RowDefinition Height="auto"/>
        <RowDefinition Height="5"/>
    </Grid.RowDefinitions>

    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="5"/>
        <ColumnDefinition Width="auto"/>
        <ColumnDefinition Width="5"/>
        <ColumnDefinition Width="*"/>
        <ColumnDefinition Width="5"/>
    </Grid.ColumnDefinitions>

    <igDP:XamDataGrid  x:Name="grdSysinfo" Grid.Row="1" Grid.Column="3"  DataSource="{Binding ActiveSites, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged }" />
     <Button Command="{Binding UpdateAllCommand}" CommandParameter="All" Grid.Row="3" Grid.Column="1">Load All</Button>
</Grid>

Answer 1

网格没有对实际的源集合进行排序，它会对其进行排序。

如果您希望能够按照它们在UI中显示的顺序获取项目，则可以绑定到ICollectionView属性：

public class SystemInformation : ViewModelBase
{
    private ObservableCollection<Site> _activeSites;
    private RelayCommand _updateAllCommand;

    public SystemInformation() : base()
    {
        ActiveSites = new ObservableCollection<Site>();
        View = CollectionViewSource.GetDefaultView(ActiveSites);
    }

    public System.ComponentModel.ICollectionView View { get; private set; } //<-- bind to this one

    public ObservableCollection<Site> ActiveSites
    {
        get
        {
            return _activeSites;
        }
        set
        {
            Set("ActiveSites", ref _activeSites, value);
        }
    }

    public RelayCommand UpdateAllCommand
    {
        get
        {
            return _updateAllCommand
              ?? (_updateAllCommand = new RelayCommand(() => 
              {
                  foreach (var site in View.OfType<Site>())
                  {
                      //---
                  }
              }));
        }
    }
}

<igDP:XamDataGrid ... DataSource="{Binding View}" />

在mvvm light

1 个答案: