private RadSize MeasureVertically(RadSize availableSize, double offset, double bufferScale)
{
var context = new MeasureContext()
{
Offset = offset,
BufferScale = bufferScale
};
context.InitializeForVerticalMeasure(this.Layout, availableSize);
this.AvailableLength = context.AvailableLength;
var initialFirstVisibleIndex = context.FirstVisibleIndex;
if (this.IsBufferNeeded)
{
context.FirstVisibleIndex = this.GenerateTopBufferItems(context.FirstVisibleIndex, context.AvailableLength, context.Offset, context);
context.LastVisibleIndex = context.FirstVisibleIndex;
}
this.MeasureForward(ref context);
//TODO: Investigate the case with maximizing and incorrect scroll offset.
if (context.AvailableLength - context.ForwardGeneratedLength > ListViewModel.DoubleArithmetics.Ceiling(1d / IndexStorage.PrecisionMultiplier))
{
if (this.viewportItemsCount < this.Layout.VisibleLineCount)
{
// perform the measure logic again, since this difference will most probably occur when the Index tree is cleared before the measure pass
this.RecycleLocally();
context.InitializeForVerticalMeasure(this.Layout, availableSize);
if (this.IsBufferNeeded)
{
context.FirstVisibleIndex = this.GenerateTopBufferItems(context.FirstVisibleIndex, context.AvailableLength, context.Offset, context);
context.LastVisibleIndex = context.FirstVisibleIndex;
}
this.MeasureForward(ref context);
}
}
this.MeasureBackwards(ref context);
if (this.IsBufferNeeded)
{
this.GenerateBottomBufferItems(context.LastVisibleIndex, context.AvailableLength, context);
}
var desiredSize = new RadSize(context.MaxLength, context.GeneratedLength);
desiredSize.Width = Math.Min(desiredSize.Width, ListViewModel.DoubleArithmetics.Ceiling(availableSize.Width));
desiredSize.Height = Math.Min(desiredSize.Height, context.AvailableLength);
this.Layout.UpdateAverageLength(context.FirstVisibleIndex, context.LastVisibleIndex);
if (Math.Floor(context.Index) > initialFirstVisibleIndex)
{
(this.Owner as RadListView).updateService.RegisterUpdate((int)UpdateFlags.AffectsContent);
}
return(desiredSize);
}
private RadSize MeasureVertically(RadSize availableSize, double offset, double bufferScale)
{
var context = new MeasureContext()
{
Offset = offset,
BufferScale = bufferScale
};
context.InitializeForVerticalMeasure(this, availableSize);
this.AvailableLength = context.AvailableLength;
// Always start with frozen containers unitl we generate row with cells.
this.shouldGenerateFrozenContainer = true;
if (this.IsBufferNeeded)
{
context.FirstVisibleIndex = this.GenerateTopBufferItems(context.FirstVisibleIndex, context.AvailableLength, context.Offset, context);
context.LastVisibleIndex = context.FirstVisibleIndex;
}
this.MeasureForward(ref context);
////TODO: We may need an additional synchronous measure pass in case less generated length (as in the Horizontal measure)
this.MeasureBackwards(ref context);
if (this.IsBufferNeeded)
{
this.GenerateBottomBufferItems(context.LastVisibleIndex, context.AvailableLength, context);
}
this.GenerateFrozenContainers();
var desiredSize = new RadSize(context.MaxLength, context.GeneratedLength);
desiredSize.Width = Math.Min(desiredSize.Width, GridModel.DoubleArithmetics.Ceiling(availableSize.Width));
desiredSize.Height = Math.Min(desiredSize.Height, context.AvailableLength);
this.Layout.UpdateAverageLength(context.FirstVisibleIndex, context.LastVisibleIndex);
return(desiredSize);
}
