protected override void InitializeForContextCore(VirtualizingLayoutContext context)
{
var state = new GroupedLayoutState(context);
context.LayoutState = state;
base.InitializeForContextCore(context);
}
private Size ArrangeColumn(VirtualizingLayoutContext context, GroupedLayoutState state, ColumnInfo colInfo, int col, int headerIndex, double startingY, bool widthChanged, out int nextHeaderIndex)
{
// Note that you MUST call GetOrCreateElement on any items that are in the realized region... that's how
// the control tracks which elements it shouldn't dispose.
double y = startingY;
double x = col * colInfo.ColumnWidth + ColumnSpacing * col;
int i = headerIndex;
var header = state.GetItemAt(headerIndex);
var headerEl = context.GetOrCreateElementAt(headerIndex);
headerEl.Arrange(new Rect(x, y, colInfo.ColumnWidth, headerEl.DesiredSize.Height));
y += headerEl.DesiredSize.Height + AfterHeaderSpacing;
i++;
while (i < context.ItemCount)
{
if (!(context.GetItemAt(i) is ViewItemTaskOrEvent))
{
// End of column
break;
}
var item = state.GetItemAt(i);
// Logic technically ignores height of item, but heights are short enough it shouldn't matter
if (y < context.RealizationRect.Top ||
y > context.RealizationRect.Bottom)
{
y += item.Height.GetValueOrDefault(40);
}
else
{
var el = context.GetOrCreateElementAt(i);
//if (widthChanged || !item.Arranged)
{
el.Arrange(new Rect(x, y, colInfo.ColumnWidth, el.DesiredSize.Height));
}
y += el.DesiredSize.Height;
}
// Include item spacing
y += ItemSpacing;
i++;
}
// Remove last item spacing (since no item after it)
y -= ItemSpacing;
nextHeaderIndex = i;
return(new Size(colInfo.ColumnWidth, y - startingY));
}
private Size MeasureColumn(VirtualizingLayoutContext context, GroupedLayoutState state, Size availableSizeForElements, int headerIndex, double startingY, bool widthChanged, out int nextHeaderIndex)
{
// Note that you MUST call GetOrCreateElement on any items that are in the realized region... that's how
// the control tracks which elements it shouldn't dispose.
double y = startingY;
int i = headerIndex;
var header = state.GetItemAt(headerIndex);
//if (widthChanged || header.Height == null)
{
var headerEl = context.GetOrCreateElementAt(headerIndex);
headerEl.Measure(availableSizeForElements);
header.Height = headerEl.DesiredSize.Height;
}
y += header.Height.Value + AfterHeaderSpacing;
i++;
while (i < context.ItemCount)
{
if (!(context.GetItemAt(i) is ViewItemTaskOrEvent))
{
// End of column
break;
}
var item = state.GetItemAt(i);
// Logic technically ignores height of item, but heights are short enough it shouldn't matter
if (y < context.RealizationRect.Top ||
y > context.RealizationRect.Bottom)
{
y += item.Height.GetValueOrDefault(40);
}
else
{
// Theoretically since tasks/events are removed and then added back when edited, we know they can never change size...
// Therefore we can store their measured size, and only call measure if their width changed or height unknown...
// However this didn't work in reality, not sure why.
//if (widthChanged || item.Height == null)
{
var itemEl = context.GetOrCreateElementAt(i);
itemEl.Measure(availableSizeForElements);
item.Height = itemEl.DesiredSize.Height;
}
y += item.Height.Value;
}
// Include item spacing
y += ItemSpacing;
i++;
}
// Remove last item spacing (since no item after it)
y -= ItemSpacing;
nextHeaderIndex = i;
return(new Size(availableSizeForElements.Width, y - startingY));
}