Changing the color of alternate listbox item.

Question

Hi,

I have created a Listbox with a data template. I want to change the background color of every alternate listbox item.

Please let me know how to do this?

Answer 1

You may be able to bind the listbox item's background colour to some kind of code that chooses one colour for all the odd numbered items (using the list/array/collection index) and another for even numbered ones.

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Answer 2

Here's some code using a value convertor...

  public class AlternatingRowsConverter : IValueConverter
  {
    private bool _alternate;

    public object Convert(object value, Type targetType, object parameter,
               System.Globalization.CultureInfo culture)
    {
      _alternate = !_alternate;
      return _alternate
            ? new SolidColorBrush(Color.FromArgb(255, 255, 0, 0))
            : new SolidColorBrush(Color.FromArgb(255, 0, 0, 255));
    }

    public object ConvertBack(object value, Type targetType, object parameter,
                 System.Globalization.CultureInfo culture) 
    { throw new NotImplementedException(); }
  }
}

Then, listbox template:

      <ListBox ItemsSource="{Binding}"
           x:Name="Mylistbox"
           SelectionChanged="Mylistbox_SelectionChanged">
        <ListBox.ItemTemplate>
          <DataTemplate>
            <StackPanel>
              <Grid Background="{Binding Converter={StaticResource alternateConvertor}}">
                <TextBlock Grid.Column="0"
                      Text="{Binding Name, Mode=TwoWay}"
                      VerticalAlignment="Center"
                      HorizontalAlignment="Left" />
              </Grid>
            </StackPanel>
          </DataTemplate>
        </ListBox.ItemTemplate>
      </ListBox>

and finally define the convertor object in the resource dictionary:

  <phone:PhoneApplicationPage.Resources>
    <WindowsPhoneApplication5:AlternatingRowsConverter x:Key="alternateConvertor" />
  </phone:PhoneApplicationPage.Resources>

Probably the converter shouldn't rely on the call sequence but should retrieve the list index but this should get you started.

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