Question

I’m writing an application which reads data from an XML file and I use previous/next buttons to cycle through each record. However, I’d like to know how to use a button to select a random record. My Previous/Next buttons are as follows:

private void Next_Click(object sender, RoutedEventArgs e)
{
        var button = (Button)sender;
        var cvs = (CollectionViewSource)button.Tag;
        cvs.View.MoveCurrentToPrevious();

        if (cvs.View.IsCurrentBeforeFirst)
        {
            cvs.View.MoveCurrentToLast();
        }
}

private void Previous_Click(object sender, RoutedEventArgs e)
{
        var button = (Button)sender;
        var cvs = (CollectionViewSource)button.Tag;
        cvs.View.MoveCurrentToNext();

        if (cvs.View.IsCurrentAfterLast)
        {
            cvs.View.MoveCurrentToFirst();
        }
}

private void Random_Click(object sender, RoutedEventArgs e)
{

}

I’ve searched everywhere for a solution, including Microsoft documentation (http://msdn.microsoft.com/en-us/library/system.random.aspx) but I’m still stumped. Any help will be greatly appreciated.

Answer 1

This should work:

readonly Random _random = new Random();
private void Random_Click(object sender, RoutedEventArgs e)
{
    var button = (Button)sender;
    var cvs = (CollectionViewSource)button.Tag;
    var view = cvs.View as CollectionView;
    if (view != null)
    {
        cvs.View.MoveCurrentToPosition(_random.Next(0, view.Count));
    }
}

All views in the default WPF classes not only implement ICollectionView but should be subclasses of CollectionView which has a Count that can be used.