WPF/Metro-style: Making ListView show only complete items

Question

In my Metro application, I have a data source containing a certain number of items (say 25). I have a ListView that presents those items. My problem is that the ListView hav

Answer 1

My final solution was to combine the suggestions of @NovitchiS and @JesuX.

I created a stack panel override, and listened to the LayoutUpdated event. My final solution:

class HeightLimitedStackPanel : StackPanel
{
    public HeightLimitedStackPanel() : base()
    {
        this.LayoutUpdated += OnLayoutUpdated;
    }

    double GetSizeOfVisibleChildren(double parentHeight)
    {
        double currentSize = 0;
        bool hasBreaked = false;
        for (int i = 0; i < Children.Count; i++)
        {
            var child = Children[i];
            if (currentSize + child.DesiredSize.Height > parentHeight)
            {
                hasBreaked = true;
                break;
            }
            currentSize += child.DesiredSize.Height;
        }
        if (hasBreaked) return currentSize;

        return parentHeight;
    }

    double ParentHeight
    {
        get 
        {
            ItemsPresenter parent = VisualTreeHelper.GetParent(this) as ItemsPresenter;
            if (parent == null)
                return 0;

            return parent.ActualHeight;
        }
    }

    double previousHeight = 0;
    int previousChildCount = 0;
    protected void OnLayoutUpdated(object sender, object e)
    {
        double height = ParentHeight;
        if (height == previousHeight && previousChildCount == Children.Count) return;
        previousHeight = height;
        previousChildCount = Children.Count;

        this.Height = GetSizeOfVisibleChildren(height);
    }
}

Answer 2

ListView inherits from ItemsControl, so one more optimized solution consists in injecting custom panel (overriding measure by custom clipping display) in ItemsPanel

something like this(sorry, i did not try to compile):

protected override Size MeasureOverride(Size constraint)
{
 if (this.VisualChildrenCount <= 0)
  return base.MeasureOverride(constraint);
 var size = ne Size(constraint.Width,0);
 for(int i = 0; i < this.visualChildrenCount; i++)
 {
  child.Measure(size);
  if(size.height + child.desiredSize > constraint.height)
   break;
  size.Height += child.DesiredSize;
 }
 return size;
}

Answer 3

The answer from @JesuX is the better approach -- if done correctly. The following ListView subclass works fine for me:

public sealed class IntegralItemsListView : ListView
{
    protected override Size MeasureOverride(Size availableSize)
    {
        Size size = base.MeasureOverride(availableSize);
        double height = 0;
        if (Items != null)
        {
            for (int i = 0; i < Items.Count; ++i)
            {
                UIElement itemContainer = (UIElement)ContainerFromIndex(i);
                if (itemContainer == null)
                {
                    break;
                }

                itemContainer.Measure(availableSize);
                double childHeight = itemContainer.DesiredSize.Height;
                if (height + childHeight > size.Height)
                {
                    break;
                }

                height += childHeight;
            }
        }

        size.Height = height;
        return size;
    }
}

One caveat -- if you plop an IntegralItemsListView into a Grid, it will have

VerticalAlignment="Stretch"

by default, which defeats the purpose of this class.

Also: If the items are of uniform height, the method can obviously be simplified:

protected override Size MeasureOverride(Size availableSize)
{
    Size size = base.MeasureOverride(availableSize);
    size.Height = (int)(size.Height / ItemHeight) * ItemHeight;
    return size;
}