List Items Vertically on a WrapPanel and take advantage of multiple columns

Question

I need to list items (all of same size) vertically (with a ScrollViewer). I want the items to spread through x columns if the container is large enough to display

Answer 1

Finally got something that works but it needs code. I agree with all of you when you say that we need to resize height of the WrapPanel to make that works. Here is my solution :

Here is the CodeBehind :

private void ScrollViewer_SizeChanged(object sender, SizeChangedEventArgs e)
{
    // Stupid magical number because ViewPortHeight is sometimes not accurate
    Double MAGICALNUMBER = 2;

    // Ensure ViewPortSize is not 0
    if (scroll1.ViewportWidth <= MAGICALNUMBER || scroll1.ViewportHeight <= MAGICALNUMBER)
        return;

    Size contentSize = new Size(scroll1.ViewportWidth - MAGICALNUMBER, scroll1.ViewportHeight - MAGICALNUMBER);
    Size itemSize = new Size(wp1.ItemWidth, wp1.ItemHeight);

    Size newSize = CalculateSizeBasedOnContent(contentSize, wp1.Children.Count, itemSize);

    wp1.Width = newSize.Width;
    wp1.Height = newSize.Height;
}


private Size CalculateSizeBasedOnContent(Size containerSize, int itemsCount, Size itemSize)
{

    int iPossibleColumns = (int)Math.Floor(containerSize.Width / itemSize.Width);
    int iPossibleRows = (int)Math.Floor(containerSize.Height / itemSize.Height);

    // If all items can fit in first column without scrolling (or if container is narrow than the itemWidth)
    if (itemsCount <= iPossibleRows || containerSize.Width < itemSize.Width)
    return new Size(itemSize.Width, (itemsCount * itemSize.Height));

    // If all items can fit in columns without scrollbar
    if (iPossibleColumns * iPossibleRows > itemsCount)
    {
    int columnsNeededForDisplay = (int)Math.Ceiling((itemsCount/(Double) iPossibleRows));
    return new Size(columnsNeededForDisplay * itemSize.Width, containerSize.Height);
    }

    // Here scrolling is needed even after spreading in columns
    int itemsPerColumn = (int)Math.Ceiling(wp1.Children.Count / (Double)iPossibleColumns);
    return new Size(containerSize.Width, itemsPerColumn * itemSize.Height);

}