/// <summary>
/// Calls the <see cref="OnAttachedToVisualTree(VisualTreeAttachmentEventArgs)"/> method
/// for this control and all of its visual descendents.
/// </summary>
/// <param name="e">The event args.</param>
private void NotifyAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
{
_visualLogger.Verbose("Attached to visual tree");
_isAttachedToVisualTree = true;
if (Name != null && e.NameScope != null)
{
e.NameScope.Register(Name, this);
}
OnAttachedToVisualTree(e);
if (_visualChildren != null)
{
foreach (Visual child in _visualChildren.OfType <Visual>())
{
var ce = child.GetAttachmentEventArgs(e);
child.NotifyAttachedToVisualTree(ce);
}
}
}
/// <summary>
/// Calls the <see cref="OnDetachedFromVisualTree(VisualTreeAttachmentEventArgs)"/> method
/// for this control and all of its visual descendents.
/// </summary>
/// <param name="e">The event args.</param>
private void NotifyDetachedFromVisualTree(VisualTreeAttachmentEventArgs e)
{
_visualLogger.Verbose("Detached from visual tree");
VisualRoot = null;
OnDetachedFromVisualTree(e);
if (VisualChildren != null)
{
foreach (Visual child in VisualChildren.OfType<Visual>())
{
child.NotifyDetachedFromVisualTree(e);
}
}
}
/// <summary>
/// Calls the <see cref="OnAttachedToVisualTree(VisualTreeAttachmentEventArgs)"/> method
/// for this control and all of its visual descendents.
/// </summary>
/// <param name="e">The event args.</param>
private void NotifyAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
{
_visualLogger.Verbose("Attached to visual tree");
VisualRoot = e.Root;
OnAttachedToVisualTree(e);
if (VisualChildren != null)
{
foreach (Visual child in VisualChildren.OfType<Visual>())
{
child.NotifyAttachedToVisualTree(e);
}
}
}
/// <summary>
/// Sets the visual parent of the Visual.
/// </summary>
/// <param name="value">The visual parent.</param>
private void SetVisualParent(Visual value)
{
if (_visualParent == value)
{
return;
}
var old = _visualParent;
_visualParent = value;
if (VisualRoot != null)
{
var e = new VisualTreeAttachmentEventArgs(VisualRoot);
NotifyDetachedFromVisualTree(e);
}
if (_visualParent is IRenderRoot || _visualParent?.IsAttachedToVisualTree == true)
{
var root = this.GetVisualAncestors().OfType<IRenderRoot>().FirstOrDefault();
var e = new VisualTreeAttachmentEventArgs(root);
NotifyAttachedToVisualTree(e);
}
RaisePropertyChanged(VisualParentProperty, old, value, BindingPriority.LocalValue);
}
/// <summary>
/// Called when the control is removed from a visual tree.
/// </summary>
/// <param name="e">The event args.</param>
/// <remarks>
/// It is vital that if you override this method you call the base implementation;
/// failing to do so will cause numerous features to not work as expected.
/// </remarks>
protected virtual void OnDetachedFromVisualTree(VisualTreeAttachmentEventArgs e)
{
if (RenderTransform != null)
{
RenderTransform.Changed -= RenderTransformChanged;
}
DetachedFromVisualTree?.Invoke(this, e);
}
/// <summary>
/// Calls the <see cref="OnDetachedFromVisualTree(VisualTreeAttachmentEventArgs)"/> method
/// for this control and all of its visual descendents.
/// </summary>
/// <param name="e">The event args.</param>
private void NotifyDetachedFromVisualTree(VisualTreeAttachmentEventArgs e)
{
_visualLogger.Verbose("Detached from visual tree");
if (Name != null && e.NameScope != null)
{
e.NameScope.Unregister(Name);
}
_isAttachedToVisualTree = false;
OnDetachedFromVisualTree(e);
if (_visualChildren != null)
{
foreach (Visual child in _visualChildren.OfType<Visual>())
{
var ce = child.GetAttachmentEventArgs(e);
child.NotifyDetachedFromVisualTree(ce);
}
}
}
/// <summary>
/// Calls the <see cref="OnAttachedToVisualTree(VisualTreeAttachmentEventArgs)"/> method
/// for this control and all of its visual descendents.
/// </summary>
/// <param name="e">The event args.</param>
private void NotifyAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
{
_visualLogger.Verbose("Attached to visual tree");
_isAttachedToVisualTree = true;
if (Name != null && e.NameScope != null)
{
e.NameScope.Register(Name, this);
}
OnAttachedToVisualTree(e);
if (_visualChildren != null)
{
foreach (Visual child in _visualChildren.OfType<Visual>())
{
var ce = child.GetAttachmentEventArgs(e);
child.NotifyAttachedToVisualTree(ce);
}
}
}
/// <summary>
/// Gets the <see cref="VisualTreeAttachmentEventArgs"/> for this element based on the
/// parent's args.
/// </summary>
/// <param name="e">The parent args.</param>
/// <returns>The args for this element.</returns>
private VisualTreeAttachmentEventArgs GetAttachmentEventArgs(VisualTreeAttachmentEventArgs e)
{
var childNameScope = (this as INameScope) ?? NameScope.GetNameScope(this);
if (childNameScope != null)
{
return new VisualTreeAttachmentEventArgs(e.Root, childNameScope);
}
else
{
return e;
}
}
/// <summary>
/// Called when the control is removed from a visual tree.
/// </summary>
/// <param name="e">The event args.</param>
protected virtual void OnDetachedFromVisualTree(VisualTreeAttachmentEventArgs e)
{
DetachedFromVisualTree?.Invoke(this, e);
}
/// <summary>
/// Called when the control is added to a visual tree.
/// </summary>
/// <param name="e">The event args.</param>
protected virtual void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
{
AttachedToVisualTree?.Invoke(this, e);
}
/// <summary>
/// Called when the control is removed from a visual tree.
/// </summary>
/// <param name="e">The event args.</param>
protected virtual void OnDetachedFromVisualTree(VisualTreeAttachmentEventArgs e)
{
DetachedFromVisualTree?.Invoke(this, e);
}
/// <summary>
/// Called when the control is added to a visual tree.
/// </summary>
/// <param name="e">The event args.</param>
protected virtual void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
{
AttachedToVisualTree?.Invoke(this, e);
}