Setting selected items in a GridView

Question

If I have a collection of items bound to my GridView, and each item has a property IsSelected, how can I make sure the state of that GridViewItem is selected?

I've tried binding the property in the ItemContainerStyle with no luck.

Am I better off using an ItemTemplateSelector you think? Maybe I'll try that while I wait for any feedback.

Answer 1

This has always been a pain due to the lack of support for Value's binding in the Style's Setter in Winrt, but there is a workaround for that, which has been adapted to winrt (it originally targets the same limitation in Silverlight 4 - ps: Slverlight 5 support binding in Setters-), you can check it here,

but even so, for some reason this also doesn't work in Winrt :

<GridView SelectionMode="Multiple" HorizontalAlignment="Stretch">
    <GridView .ItemContainerStyle>
        <Style TargetType="ListViewItem">
            <Setter Property="IsSelected" Value="True"/>
        </Style>
    </GridView .ItemContainerStyle>

Now unless you find a better solution, here a little hack inspired from here that doesn't look so clean, but it do the trick

• Extend the GridView class

  using Windows.UI.Xaml;
  using Windows.UI.Xaml.Controls;
  using Windows.UI.Xaml.Controls.Primitives;
  using Windows.UI.Xaml.Data;
  public class GridViewEx : GridView
  {
      protected override void    PrepareContainerForItemOverride(Windows.UI.Xaml.DependencyObject element, object item)
     {
         base.PrepareContainerForItemOverride(element, item);
         var gridItem = element as GridViewItem;
         var binding = new Binding { Mode = BindingMode.TwoWay, Source =    item, Path = new PropertyPath("IsSelected") };
         gridItem.SetBinding(SelectorItem.IsSelectedProperty, binding);
     }
  }
  

• Make sure that IsSelected property is present in your GridView ItemSource Collection

  public class Item
  {
     public String Name { get; set; }
     public bool IsSelected { get; set; }         
  }
  // ..
  public ObservableCollection<Item> ListItems
  {
      get
      {
          return _listItems;
      }
  
      set
      {
          if (_listItems == value)
          {
              return;
          }
  
          _listItems = value;
          OnPropertyChanged();
      }
  }
  

• and you are good to go

  <local:GridViewEx SelectionMode="Multiple"  ItemsSource="{Binding ListItems}" >
         <local:GridViewEx.ItemTemplate>
          <DataTemplate>
              <StackPanel Orientation="Horizontal">
                  <TextBlock Text="{Binding Name}"></TextBlock>
              </StackPanel>
          </DataTemplate>
      </local:GridViewEx.ItemTemplate>
  </local:GridViewEx>