private void RemoveCore(PointerCaptureTarget target, PointerCaptureKind kinds)
{
global::System.Diagnostics.Debug.Assert(
kinds != PointerCaptureKind.None,
"The capture kind must be set to release pointer captures.");
if (this.Log().IsEnabled(LogLevel.Information))
{
this.Log().Info($"{target.Element.GetDebugName()}: Releasing ({kinds}) capture of pointer {Pointer}");
}
// If we remove an explicit capture, we update the _localExplicitCaptures of the target element
if (kinds.HasFlag(PointerCaptureKind.Explicit) &&
target.Kind.HasFlag(PointerCaptureKind.Explicit))
{
target.Element._localExplicitCaptures.Remove(Pointer);
}
target.Kind &= ~kinds;
// The element is no longer listening for events, remove it.
if (target.Kind == PointerCaptureKind.None)
{
_targets.Remove(target.Element);
}
IsImplicitOnly = _targets.None(t => t.Value.Kind.HasFlag(PointerCaptureKind.Explicit));
// Validate / update the state of this capture
EnsureEffectiveCaptureState();
}
/// <summary>
/// Removes a UIElement from the targets of this capture.
/// DO NOT USE directly, use instead the Release method on the UIElement in order to properly raise the PointerCaptureLost event.
/// </summary>
public PointerCaptureKind RemoveTarget(UIElement element, PointerCaptureKind kinds, out PointerRoutedEventArgs lastDispatched)
{
if (_targets.TryGetValue(element, out var target))
{
// Validate if any of the requested kinds is handled
if ((target.Kind & kinds) == 0)
{
lastDispatched = default;
return(PointerCaptureKind.None);
}
}
else
{
lastDispatched = default;
return(PointerCaptureKind.None);
}
var removed = target.Kind & kinds;
lastDispatched = target.LastDispatched;
RemoveCore(target, kinds);
return(removed);
}
public bool TryAddTarget(UIElement element, PointerCaptureKind kind, PointerRoutedEventArgs relatedArgs = null)
{
global::System.Diagnostics.Debug.Assert(
kind == PointerCaptureKind.Explicit || kind == PointerCaptureKind.Implicit,
"The initial capture kind must be Explicit **OR** Implicit.");
if (this.Log().IsEnabled(LogLevel.Information))
{
this.Log().Info($"{element}: Capturing ({kind}) pointer {Pointer}");
}
if (_targets.TryGetValue(element, out var target))
{
// Validate if the requested kind is not already handled
if (target.Kind.HasFlag(kind))
{
return(false);
}
else
{
// Add the new kind to the target
target.Kind |= kind;
}
}
else
{
target = new PointerCaptureTarget(element, kind);
_targets.Add(element, target);
// If the capture is made while raising an event (usually captures are made in PointerPressed handlers)
// we re-use the current event args (if they match) to init the target.LastDispatched property.
// Note: we don't check the sender as we may capture on another element but the frame ID is still correct.
if (relatedArgs?.Pointer == Pointer)
{
Update(target, relatedArgs);
// In case of an implicit capture we also override the native element used for the capture.
// cf. remarks of the PointerCaptureTarget.NativeCaptureElement.
if (kind == PointerCaptureKind.Implicit)
{
target.NativeCaptureElement = relatedArgs?.OriginalSource as UIElement ?? element;
}
}
}
// If we added an explicit capture, we update the _localExplicitCaptures of the target element
if (kind == PointerCaptureKind.Explicit)
{
IsImplicitOnly = false;
element._localExplicitCaptures.Add(Pointer);
}
// Make sure that this capture is effective
EnsureEffectiveCaptureState();
return(true);
}
public PointerCaptureTarget(UIElement element, PointerCaptureKind kind)
{
NativeCaptureElement = Element = element;
Kind = kind;
}
public IEnumerable <PointerCaptureTarget> GetTargets(PointerCaptureKind kinds) => _targets .Values .Where(target => (target.Kind & kinds) != PointerCaptureKind.None);
public bool IsTarget(UIElement element, PointerCaptureKind kinds) => _targets.TryGetValue(element, out var target) && (target.Kind & kinds) != PointerCaptureKind.None;
