如何使用MVVM从DataGrid获取SelectedItems

Question

I am building a WPF application using C# and also i used MVVM architecture in my application. I created a CheckBox column in telerik gridview by using DataTemplate . I am using a collection to bind the data in the GridView .

How can i find the particular row number of DataItem has been selected in that Collection When CheckBox is checked on the Grid.

Here My code for creating CheckBox on Grid is:

<telerik:GridViewDataColumn.CellTemplate>
                        <DataTemplate>
                            <StackPanel Orientation="Horizontal" HorizontalAlignment="Center" VerticalAlignment="Center">
                                <CheckBox Name="StockCheckBox" IsChecked="{Binding RelativeSource={RelativeSource AncestorType={x:Type telerik:GridViewRow}}, Path=IsSelected}" />
                             </StackPanel>
                        </DataTemplate>
                    </telerik:GridViewDataColumn.CellTemplate>

And My Collection is,

   foreach (var AvailableStock in AvailableStocks)// In this **AvailableStocks**(IEnumurable Collection) I got all the datas in the Gridview 
        //In this collection How can i know that the particular RowItem is selected in that gridview by CheckBox
      {
          if (SelectedStock != null)
          {
             this.SelectedStocks.Add(AvailableStock );

             this.RaisePropertyChanged(Member.Of(() => AvailableStocks));
          }
      }

Anyone Please tell me some suggestion on this How can i achieve this? How can i identify that particular row has been selected ?

Thanks in Advance.

Answer 1

I would recommend using an MVVM approach and use a Binding to get the selected items. Unfortunately, the DataGrid doesn't provide a DependencyProperty for selected items, but you can provide your own. Derive a class from DataGrid, register a dependency property for SelectedItems and override the SelectionChanged event to update your dependency property. You can then use a Binding to inform your ViewModel of the selected items.

Code:

public class CustomDataGrid : DataGrid
{
    public static readonly DependencyProperty CustomSelectedItemsProperty = DependencyProperty.Register(
        "CustomSelectedItems", typeof (List<object>), typeof (CustomDataGrid), 
        new PropertyMetadata(new List<object>()));

    public List<object> CustomSelectedItems
    {
        get { return (List<object>) GetValue(CustomSelectedItemsProperty); }
        set { SetValue(CustomSelectedItemsProperty, value);}
    }

    protected override void OnSelectionChanged(SelectionChangedEventArgs e)
    {
        foreach(var item in e.AddedItems)
            CustomSelectedItems.Add(item);
        foreach (var item in e.RemovedItems)
            CustomSelectedItems.Remove(item);
        base.OnSelectionChanged(e);
    }
}

XAML:

<Grid>
    <Ctrl:CustomDataGrid CustomSelectedItems="{Binding MySelectedItems}"/>
</Grid>