protected override void Dispose(bool disposing)
{
if (_disposed)
{
return;
}
if (disposing)
{
if (_formsCell != null)
{
_formsCell.PropertyChanged -= CellPropertyChanged;
}
CustomCell = null;
_heightConstraint?.Dispose();
_heightConstraint = null;
IVisualElementRenderer renderer = null;
if (_rendererRef != null &&
_rendererRef.TryGetTarget(out renderer) &&
renderer.Element != null)
{
FormsInternals.DisposeModelAndChildrenRenderers(renderer.Element);
_rendererRef = null;
}
renderer?.Dispose();
_formsCell = null;
}
_disposed = true;
base.Dispose(disposing);
}
public virtual void UpdateCell(View cell, UITableView tableView)
{
if (_formsCell == cell &&
!CustomCell.IsForceLayout)
{
return;
}
CustomCell.IsForceLayout = false;
if (_formsCell != null)
{
_formsCell.PropertyChanged -= CellPropertyChanged;
}
_formsCell = cell;
_formsCell.PropertyChanged += CellPropertyChanged;
if (_rendererRef == null ||
!_rendererRef.TryGetTarget(out IVisualElementRenderer renderer))
{
renderer = GetNewRenderer();
}
else
{
if (renderer.Element != null &&
renderer == Platform.GetRenderer(renderer.Element))
{
renderer.Element.ClearValue(FormsInternals.RendererProperty);
}
Type type = Xamarin.Forms.Internals.Registrar.Registered.GetHandlerTypeForObject(_formsCell);
// ReSharper disable once SuspiciousTypeConversion.Global
if (renderer is IReflectableType reflectable)
{
Type rendererType = reflectable.GetTypeInfo().AsType();
if (rendererType == type ||
(renderer.GetType() == FormsInternals.DefaultRenderer) && type == null)
{
renderer.SetElement(_formsCell);
}
else
{
//when cells are getting reused the element could be already set to another cell
//so we should dispose based on the renderer and not the renderer.Element
FormsInternals.DisposeRendererAndChildren(renderer);
renderer = GetNewRenderer();
}
}
}
Platform.SetRenderer(_formsCell, renderer);
if (!CustomCell.IsMeasureOnce ||
tableView.Frame.Width != _lastFrameWidth)
{
_lastFrameWidth = tableView.Frame.Width;
nfloat width = tableView.Frame.Width -
(CustomCell.UseFullSize
? 0
: 32); // CellBaseView layout margin
if (renderer.Element != null)
{
SizeRequest result = renderer.Element.Measure(tableView.Frame.Width, double.PositiveInfinity, MeasureFlags.IncludeMargins);
_lastMeasureWidth = result.Request.Width;
if (_formsCell.HorizontalOptions.Alignment == LayoutAlignment.Fill)
{
_lastMeasureWidth = width;
}
_lastMeasureHeight = result.Request.Height;
}
if (_heightConstraint != null)
{
_heightConstraint.Active = false;
_heightConstraint?.Dispose();
}
_heightConstraint = renderer.NativeView.HeightAnchor.ConstraintEqualTo((nfloat)_lastMeasureHeight);
_heightConstraint.Priority = 999f;
_heightConstraint.Active = true;
renderer.NativeView.UpdateConstraintsIfNeeded();
}
Layout.LayoutChildIntoBoundingRegion(_formsCell, new Rectangle(0, 0, _lastMeasureWidth, _lastMeasureHeight));
UpdateNativeCell();
}
