VisualElement Class
Definition
Important
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A Element that occupies an area on the screen, has a visual appearance, and can obtain touch input.
public class VisualElement : Xamarin.Forms.NavigableElement, Xamarin.Forms.IAnimatable, Xamarin.Forms.ITabStopElement, Xamarin.Forms.IVisualElementControllertype VisualElement = class
inherit NavigableElement
interface IAnimatable
interface IVisualElementController
interface IElementController
interface ITabStopElement- Inheritance
- Derived
- Implements
Remarks
The base class for most Xamarin.Forms on-screen elements. Provides most properties, events, and methods for presenting an item on screen.
Constructors
| VisualElement() |
Fields
| AnchorXProperty |
Identifies the AnchorX bindable property. |
| AnchorYProperty |
Identifies the AnchorY bindable property. |
| BackgroundColorProperty |
Identifies the BackgroundColor bindable property. |
| BackgroundProperty | |
| BehaviorsProperty |
Identifies the Behaviors bindable property. |
| ClipProperty | |
| FlowDirectionProperty |
Backing store for the FlowDirection property. |
| HeightProperty |
Identifies the Height bindable property. |
| HeightRequestProperty |
Backing store for the HeightRequest property. |
| InputTransparentProperty |
Identifies the InputTransparent bindable property. |
| IsEnabledProperty |
Identifies the IsEnabled bindable property. |
| IsFocusedProperty |
Identifies the IsFocused bindable property. |
| IsFocusedPropertyKey |
For internal use by the Xamarin.Forms platform. |
| IsTabStopProperty |
The backing store for the IsTabStop field. |
| IsVisibleProperty |
Identifies the IsVisible bindable property. |
| MinimumHeightRequestProperty |
Backing store for the MinimumHeightRequest property. |
| MinimumWidthRequestProperty |
Backing store for the MinimumWidthRequest property. |
| NavigationProperty | |
| OpacityProperty |
Identifies the Opacity bindable property. |
| RotationProperty |
Identifies the Rotation bindable property. |
| RotationXProperty |
Identifies the RotationX bindable property. |
| RotationYProperty |
Identifies the RotationY bindable property. |
| ScaleProperty |
Identifies the Scale bindable property. |
| ScaleXProperty |
Backing store for the ScaleX property. |
| ScaleYProperty |
Backing store for the ScaleY property. |
| StyleProperty | |
| TabIndexProperty |
The backing store for the TabIndex field. |
| TranslationXProperty |
Identifies the TranslationX bindable property. |
| TranslationYProperty |
Identifies the TranslationY bindable property. |
| TriggersProperty |
Identifies the Triggers bindable property. |
| VisualProperty |
The backing store for the Visual field. |
| WidthProperty |
Identifies the Width bindable property. |
| WidthRequestProperty |
Backing store for the WidthRequest property. |
| XProperty |
Identifies the X bindable property. |
| YProperty |
Identifies the Y bindable property. |
Properties
| AnchorX |
Gets or sets the X component of the center point for any transform, relative to the bounds of the element. This is a bindable property. |
| AnchorY |
Gets or sets the Y component of the center point for any transform, relative to the bounds of the element. This is a bindable property. |
| AutomationId |
Gets or sets a value that allows the automation framework to find and interact with this element. (Inherited from Element) |
| Background | |
| BackgroundColor |
Gets or sets the color which will fill the background of a VisualElement. This is a bindable property. |
| Batched |
For internal use by the Xamarin.Forms platform. |
| Behaviors |
Gets the list of Behaviors associated to this element. This is a bindable property. |
| BindingContext |
Gets or sets object that contains the properties that will be targeted by the bound properties that belong to this BindableObject. (Inherited from BindableObject) |
| Bounds |
Gets the bounds of the element. |
| class | (Inherited from NavigableElement) |
| ClassId |
Gets or sets a value used to identify a collection of semantically similar elements. (Inherited from Element) |
| Clip | |
| DisableLayout |
For internal use by the Xamarin.Forms platform. |
| Dispatcher | (Inherited from BindableObject) |
| EffectControlProvider |
For internal use by the Xamarin.Forms platform. (Inherited from Element) |
| Effects |
A list of the effects that are applied to this item. (Inherited from Element) |
| FlowDirection |
Gets or sets the layout flow direction. |
| Height |
Gets the current rendered height of this element. This is a read-only bindable property. |
| HeightRequest |
Gets or sets the desired height override of this element. |
| Id |
Gets a value that can be used to uniquely identify an element through the run of an application. (Inherited from Element) |
| InputTransparent |
Gets or sets a value indicating whether this element should be involved in the user interaction cycle. This is a bindable property. |
| IsEnabled |
Gets or sets a value indicating whether this element is enabled in the user interface. This is a bindable property. |
| IsFocused |
Gets a value indicating whether this element is focused currently. This is a bindable property. |
| IsInNativeLayout |
For internal use by the Xamarin.Forms platform. |
| IsNativeStateConsistent |
For internal use by the Xamarin.Forms platform. |
| IsPlatformEnabled |
For internal use by the Xamarin.Forms platform. |
| IsTabStop |
Gets or sets a value that indicates whether this element is included in tab navigation. This is a bindable property. |
| IsVisible |
Gets or sets a value that determines whether this elements should be part of the visual tree or not. This is a bindable property. |
| LogicalChildren |
For internal use by the Xamarin.Forms platform. (Inherited from Element) |
| MinimumHeightRequest |
Gets or sets a value which overrides the minimum height the element will request during layout. |
| MinimumWidthRequest |
Gets or sets a value which overrides the minimum width the element will request during layout. |
| Navigation | (Inherited from NavigableElement) |
| NavigationProxy | (Inherited from NavigableElement) |
| Opacity |
Gets or sets the opacity value applied to the element when it is rendered. This is a bindable property. |
| Parent |
Gets or sets the parent element of the element. (Inherited from Element) |
| ParentView |
Obsolete.
Gets the element which is the closest ancestor of this element that is a VisualElement. (Inherited from Element) |
| Platform |
Obsolete.
(Inherited from Element)
|
| RealParent |
For internal use by the Xamarin.Forms platform. (Inherited from Element) |
| Resources |
Gets or sets the local resource dictionary. |
| Rotation |
Gets or sets the rotation (in degrees) about the Z-axis (affine rotation) when the element is rendered. |
| RotationX |
Gets or sets the rotation (in degrees) about the X-axis (perspective rotation) when the element is rendered. |
| RotationY |
Gets or sets the rotation (in degrees) about the Y-axis (perspective rotation) when the element is rendered. |
| Scale |
Gets or sets the scale factor applied to the element. |
| ScaleX |
Gets or sets a scale value to apply to the X direction. |
| ScaleY |
Gets or sets a scale value to apply to the Y direction. |
| Style | (Inherited from NavigableElement) |
| StyleClass | (Inherited from NavigableElement) |
| StyleId |
Gets or sets a user defined value to uniquely identify the element. (Inherited from Element) |
| TabIndex | |
| TranslationX |
Gets or sets the X translation delta of the element. |
| TranslationY |
Gets or sets the Y translation delta of the element. |
| Triggers |
Gets the list of Trigger associated to this element. This is a bindable property. |
| Visual | |
| Width |
Gets the current rendered width of this element. This is a read-only bindable property. |
| WidthRequest |
Gets or sets the desired width override of this element. |
| X |
Gets the current X position of this element. This is a read-only bindable property. |
| Y |
Gets the current Y position of this element. This is a read-only bindable property. |
Methods
| ApplyBindings() |
Apply the bindings to BindingContext. (Inherited from BindableObject) |
| BatchBegin() |
Signals the start of a batch of changes to the elements properties. |
| BatchCommit() |
Signals the end of a batch of commands to the element and that those commands should now be committed. |
| ChangeVisualState() |
For internal use by the Xamarin.Forms platform. |
| ClearValue(BindableProperty) |
Clears any value set by SetValue for |
| ClearValue(BindablePropertyKey) |
Clears any value set by SetValue for the property that is identified by |
| CoerceValue(BindableProperty) | (Inherited from BindableObject) |
| CoerceValue(BindablePropertyKey) | (Inherited from BindableObject) |
| Descendants() |
For internal use by the Xamarin.Forms platform. (Inherited from Element) |
| EffectIsAttached(String) |
For internal use by the Xamarin.Forms platform. (Inherited from Element) |
| FindByName(String) |
Returns the element that has the specified name. (Inherited from Element) |
| Focus() |
Attemps to set focus to this element. |
| GetSizeRequest(Double, Double) |
Obsolete.
Returns the SizeRequest of the element. Calling this method begins the measure pass of a layout cycle. |
| GetValue(BindableProperty) |
Returns the value that is contained in the BindableProperty. (Inherited from BindableObject) |
| GetValues(BindableProperty, BindableProperty, BindableProperty) |
Obsolete.
For internal use by the Xamarin.Forms platform. (Inherited from BindableObject) |
| GetValues(BindableProperty, BindableProperty) |
Obsolete.
For internal use by the Xamarin.Forms platform. (Inherited from BindableObject) |
| InvalidateMeasure() |
Method that is called to invalidate the layout of this VisualElement. Raises the MeasureInvalidated event. |
| InvalidateMeasureNonVirtual(InvalidationTrigger) |
For internal use by the Xamarin.Forms platform. |
| IsSet(BindableProperty) |
Returns |
| Layout(Rectangle) |
Updates the bounds of the element during the layout cycle. |
| Measure(Double, Double, MeasureFlags) |
Returns the minimum size that a visual element needs in order to be displayed on the device. |
| NativeSizeChanged() |
For internal use by the Xamarin.Forms platform. |
| OnBindingContextChanged() | |
| OnChildAdded(Element) |
Application developers can override this method to respond when a child is added. |
| OnChildRemoved(Element, Int32) | |
| OnChildRemoved(Element) |
Obsolete.
Application developers can override this method to respond when a child is removed. |
| OnChildrenReordered() |
Invoked whenever the ChildrenReordered event is about to be emitted. Implement this method to add class handling for this event. |
| OnMeasure(Double, Double) |
Method that is called when a layout measurement happens. |
| OnParentSet() | (Inherited from NavigableElement) |
| OnPropertyChanged(String) |
Method that is called when a bound property is changed. (Inherited from Element) |
| OnPropertyChanging(String) |
Call this method from a child class to notify that a change is going to happen on a property. (Inherited from BindableObject) |
| OnSizeAllocated(Double, Double) |
This method is called when the size of the element is set during a layout cycle. This method is called directly before the SizeChanged event is emitted. Implement this method to add class handling for this event. |
| OnSizeRequest(Double, Double) |
Obsolete.
This method is called during the measure pass of a layout cycle to get the desired size of an element. |
| OnTabIndexPropertyChanged(Int32, Int32) | |
| OnTabStopPropertyChanged(Boolean, Boolean) | |
| RemoveBinding(BindableProperty) |
Removes a previously set binding. (Inherited from BindableObject) |
| RemoveDynamicResource(BindableProperty) |
Removes a previously set dynamic resource (Inherited from Element) |
| SetBinding(BindableProperty, BindingBase) |
Assigns a binding to a property. (Inherited from BindableObject) |
| SetDynamicResource(BindableProperty, String) |
Sets the BindableProperty property of this element to be updated via the DynamicResource with the provided key. (Inherited from Element) |
| SetValue(BindableProperty, Object) |
Sets the value of the specified property. (Inherited from BindableObject) |
| SetValue(BindablePropertyKey, Object) |
Sets the value of the propertyKey. (Inherited from BindableObject) |
| SetValueCore(BindableProperty, Object, SetValueFlags) |
For internal use by the Xamarin.Forms platform. (Inherited from BindableObject) |
| SetValueFromRenderer(BindableProperty, Object) |
For internal use by the Xamarin.Forms platform. (Inherited from Element) |
| SetValueFromRenderer(BindablePropertyKey, Object) |
For internal use by the Xamarin.Forms platform. (Inherited from Element) |
| SizeAllocated(Double, Double) |
SizeAllocated is called during a layout cycle to signal the start of a sub-tree layout. |
| TabIndexDefaultValueCreator() | |
| TabStopDefaultValueCreator() | |
| UnapplyBindings() |
Unapplies all previously set bindings. (Inherited from BindableObject) |
| Unfocus() |
Unsets focus to this element. |
Events
| BatchCommitted |
For internal use by the Xamarin.Forms platform. |
| BindingContextChanged |
Raised whenever the BindingContext property changes. (Inherited from BindableObject) |
| ChildAdded |
Occurs whenever a child element is added to the element. (Inherited from Element) |
| ChildRemoved |
Occurs whenever a child element is removed from the element. (Inherited from Element) |
| ChildrenReordered |
Occurs when the Children of a VisualElement have been re-ordered. |
| DescendantAdded |
Occurs whenever a child element is added to the elements subtree. (Inherited from Element) |
| DescendantRemoved |
Occurs whenever a child element is removed from the elements subtree. (Inherited from Element) |
| FocusChangeRequested |
For internal use by the Xamarin.Forms platform. |
| Focused |
Occurs when the element receives focus. |
| MeasureInvalidated |
Event that is raised when the layout of a visual element is invalidated. |
| PlatformSet |
Obsolete.
(Inherited from Element)
|
| PropertyChanged |
Raised when a property has changed. (Inherited from BindableObject) |
| PropertyChanging |
Raised when a property is about to change. (Inherited from BindableObject) |
| SizeChanged |
Occurs when either the Width or the Height properties change value on this element. |
| Unfocused |
Occurs when the element loses focus. |
Explicit Interface Implementations
| IDynamicResourceHandler.SetDynamicResource(BindableProperty, String) |
For internal use by the Xamarin.Forms platform. (Inherited from BindableObject) |
| IElementController.SetValueFromRenderer(BindableProperty, Object) |
For internal use by the Xamarin.Forms platform. (Inherited from Element) |
| INameScope.RegisterName(String, Object) |
For internal use only. (Inherited from Element) |
| IVisualElementController.EffectiveFlowDirection |
Gets the effective visual flow direction for the element on the platform, taking into account the locale and logical flow settings. |
| IVisualElementController.InvalidateMeasure(InvalidationTrigger) |
This method is for internal use. |