/// <summary>
/// Arrange the children in the panel using the calculations from measure pass.
/// </summary>
/// <param name="finalSize">Total area available to arrange the controls</param>
/// <returns>Total used area</returns>
protected override System.Windows.Size ArrangeOverride(System.Windows.Size finalSize)
{
double closedExpandersTotalHeight = 0; // Total minimum height required by closed expanders and expanders with user defined height.
double openExpandersTotalHeight = 0; // Total size asked by all open expanders
foreach (UIElement child in this.Children)
{
Expander childExpander = child as Expander;
if (childExpander != null)
{
// Get a height if user has resized
double?userHeight = (double?)childExpander.GetValue(UserDefinedSizeProperty);
if (userHeight != null)
{
closedExpandersTotalHeight += (double)userHeight;
}
else if (childExpander.IsExpanded)
{
openExpandersTotalHeight += childExpander.DesiredSize.Height;
}
else
{
closedExpandersTotalHeight += childExpander.DesiredSize.Height;
}
}
else if (child as VerticalDragThumb != null)
{
closedExpandersTotalHeight += child.DesiredSize.Height;
}
}
// Start arranging
double usedHeight = 0;
double usedWidth = 0;
double openSpace = finalSize.Height - closedExpandersTotalHeight;
double openHeightDistributionFactor = openSpace / openExpandersTotalHeight; // Multiplication factor for distributing available free space
double currentChildHeight = 0;
foreach (UIElement child in this.Children)
{
Expander childExpander = child as Expander;
if (childExpander != null)
{
double?userHeight = (double?)childExpander.GetValue(UserDefinedSizeProperty);
// Find height to allocate
if (userHeight != null)
{
currentChildHeight = (double)userHeight;
}
else if (childExpander.IsExpanded)
{
currentChildHeight = child.DesiredSize.Height * openHeightDistributionFactor;
}
else
{
currentChildHeight = childExpander.DesiredSize.Height;
}
// Set height property so that its contents wont draw beyond this height
childExpander.Height = currentChildHeight - (childExpander.Margin.Top + childExpander.Margin.Bottom + childExpander.Padding.Top + childExpander.Padding.Bottom);
childExpander.Arrange(
new Rect(0,
usedHeight,
finalSize.Width,
currentChildHeight
));
childExpander.SetValue(AllocatedSizeProperty, currentChildHeight);
}
else if (child as VerticalDragThumb != null)
{
currentChildHeight = child.DesiredSize.Height;
child.Arrange(new Rect(0, usedHeight, finalSize.Width, child.DesiredSize.Height));
}
usedHeight += currentChildHeight;
usedWidth = child.DesiredSize.Width > usedWidth ? child.DesiredSize.Width : usedWidth;
}
return(new Size(finalSize.Width, usedHeight));
}