VisualElement VisualElement Class

Definition

A Element that occupies an area on the screen, has a visual appearance, and can obtain touch input.

public class VisualElement : Xamarin.Forms.Element, Xamarin.Forms.IAnimatable, Xamarin.Forms.IVisualElementController
type VisualElement = class
    inherit Element
    interface IAnimatable
    interface IVisualElementController
    interface IElementController
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.

Fields

AnchorXProperty AnchorXProperty

Identifies the AnchorX bindable property.

AnchorYProperty AnchorYProperty

Identifies the AnchorY bindable property.

BackgroundColorProperty BackgroundColorProperty

Identifies the BackgroundColor bindable property.

BehaviorsProperty BehaviorsProperty

Identifies the Behaviors bindable property.

FlowDirectionProperty FlowDirectionProperty

Backing store for the FlowDirection property.

HeightProperty HeightProperty

Identifies the Height bindable property.

HeightRequestProperty HeightRequestProperty

Backing store for the HeightRequest property.

InputTransparentProperty InputTransparentProperty

Identifies the InputTransparent bindable property.

IsEnabledProperty IsEnabledProperty

Identifies the IsEnabled bindable property.

IsFocusedProperty IsFocusedProperty

Identifies the IsFocused bindable property.

IsFocusedPropertyKey IsFocusedPropertyKey

For internal use by the Xamarin.Forms platform.

IsTabStopProperty IsTabStopProperty
IsVisibleProperty IsVisibleProperty

Identifies the IsVisible bindable property.

MinimumHeightRequestProperty MinimumHeightRequestProperty

Backing store for the MinimumHeightRequest property.

MinimumWidthRequestProperty MinimumWidthRequestProperty

Backing store for the MinimumWidthRequest property.

NavigationProperty NavigationProperty

Identifies the Navigation bindable property.

OpacityProperty OpacityProperty

Identifies the Opacity bindable property.

RotationProperty RotationProperty

Identifies the Rotation bindable property.

RotationXProperty RotationXProperty

Identifies the RotationX bindable property.

RotationYProperty RotationYProperty

Identifies the RotationY bindable property.

ScaleProperty ScaleProperty

Identifies the Scale bindable property.

ScaleXProperty ScaleXProperty

Backing store for the ScaleX property.

ScaleYProperty ScaleYProperty

Backing store for the ScaleY property.

StyleProperty StyleProperty

Backing store for the Style property.

TabIndexProperty TabIndexProperty
TranslationXProperty TranslationXProperty

Identifies the TranslationX bindable property.

TranslationYProperty TranslationYProperty

Identifies the TranslationY bindable property.

TriggersProperty TriggersProperty

Identifies the Triggers bindable property.

WidthProperty WidthProperty

Identifies the Width bindable property.

WidthRequestProperty WidthRequestProperty

Backing store for the WidthRequest property.

XProperty XProperty

Identifies the X bindable property.

YProperty YProperty

Identifies the Y bindable property.

Properties

AnchorX 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 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 AutomationId

Gets or sets a value that allows the automation framework to find and interact with this element.

(Inherited from Element)
BackgroundColor BackgroundColor

Gets or sets the color which will fill the background of a VisualElement. This is a bindable property.

Batched Batched

For internal use by the Xamarin.Forms platform.

Behaviors Behaviors

Gets the list of Behavior associated to this element. This is a bindable propery.

BindingContext 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 Bounds

Gets the bounds of the element.

class class

Gets or sets the style class of the visual element.

ClassId ClassId

Gets or sets a value used to identify a collection of semantically similar elements.

(Inherited from Element)
DisableLayout DisableLayout

For internal use by the Xamarin.Forms platform.

EffectControlProvider EffectControlProvider

For internal use by the Xamarin.Forms platform.

(Inherited from Element)
Effects Effects

A list of the effects that are applied to this item.

(Inherited from Element)
FlowDirection FlowDirection

Gets or sets the layout flow direction.

Height Height

Gets the current rendered height of this element. This is a read-only bindable property.

HeightRequest HeightRequest

Gets or sets the desired height override of this element.

Id Id

Gets a value that can be used to uniquely identify an element through the run of an application.

(Inherited from Element)
InputTransparent InputTransparent

Gets or sets a value indicating whether this element should be involved in the user interaction cycle. This is a bindable property.

IsEnabled IsEnabled

Gets or sets a value indicating whether this element is enabled in the user interface. This is a bindable property.

IsFocused IsFocused

Gets a value indicating whether this element is focused currently. This is a bindable property.

IsInNativeLayout IsInNativeLayout

For internal use by the Xamarin.Forms platform.

IsNativeStateConsistent IsNativeStateConsistent

For internal use by the Xamarin.Forms platform.

IsPlatformEnabled IsPlatformEnabled

For internal use by the Xamarin.Forms platform.

IsTabStop IsTabStop
IsVisible 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 LogicalChildren

For internal use by the Xamarin.Forms platform.

(Inherited from Element)
MinimumHeightRequest MinimumHeightRequest

Gets or sets a value which overrides the minimum height the element will request during layout.

MinimumWidthRequest MinimumWidthRequest

Gets or sets a value which overrides the minimum width the element will request during layout.

Navigation Navigation

Gets the context aware navigation interface for the element.

NavigationProxy NavigationProxy

For internal use by the Xamarin.Forms platform.

Opacity Opacity

Gets or sets the opacity value applied to the element when it is rendered. This is a bindable property.

Parent Parent

Gets or sets the parent element of the element.

(Inherited from Element)
ParentView ParentView

Gets the element which is the closest ancestor of this element that is a VisualElement.

(Inherited from Element)
Platform Platform

For internal use by the Xamarin.Forms platform.

(Inherited from Element)
RealParent RealParent

For internal use by the Xamarin.Forms platform.

(Inherited from Element)
Resources Resources

Gets or sets the local resource dictionary.

Rotation Rotation

Gets or sets the rotation about the Z-axis (affine rotation) when the element is rendered.

RotationX RotationX

Gets or sets the rotation about the X-axis (perspective rotation) when the element is rendered.

RotationY RotationY

Gets or sets the rotation about the Y-axis (perspective rotation) when the element is rendered.

Scale Scale

Gets or sets the scale factor applied to the element.

ScaleX ScaleX

Gets or sets a scale value to apply to the X direction.

ScaleY ScaleY

Gets or sets a scale value to apply to the Y direction.

Style Style

Gets or sets the style that defines how this visual element is displayed.

StyleClass StyleClass

Gets or sets the style class for the visual element.

StyleId StyleId

Gets or sets a user defined value to uniquely identify the element.

(Inherited from Element)
TabIndex TabIndex
TranslationX TranslationX

Gets or sets the X translation delta of the element.

TranslationY TranslationY

Gets or sets the Y translation delta of the element.

Triggers Triggers

Gets the list of Trigger associated to this element. This is a bindable property.

Width Width

Gets the current rendered width of this element. This is a read-only bindable property.

WidthRequest WidthRequest

Gets or sets the desired width override of this element.

X X

Gets the current X position of this element. This is a read-only bindable property.

Y Y

Gets the current Y position of this element. This is a read-only bindable property.

Methods

ApplyBindings() ApplyBindings()

Apply the bindings to BindingContext.

(Inherited from BindableObject)
BatchBegin() BatchBegin()

Signals the start of a batch of changes to the elements properties.

BatchCommit() BatchCommit()

Signals the end of a batch of commands to the element and that those commands should now be committed.

ChangeVisualState() ChangeVisualState()

For internal use by the Xamarin.Forms platform.

ClearValue(BindableProperty) ClearValue(BindableProperty)

Clears any value set by SetValue for property.

(Inherited from BindableObject)
ClearValue(BindablePropertyKey) ClearValue(BindablePropertyKey)

Clears any value set by SetValue for the property that is identified by propertyKey.

(Inherited from BindableObject)
Descendants() Descendants()

For internal use by the Xamarin.Forms platform.

(Inherited from Element)
EffectIsAttached(String) EffectIsAttached(String)

For internal use by the Xamarin.Forms platform.

(Inherited from Element)
FindByName(String) FindByName(String)

Returns the element that has the specified name.

(Inherited from Element)
Focus() Focus()

Attemps to set focus to this element.

GetSizeRequest(Double, Double) GetSizeRequest(Double, Double)

Returns the SizeRequest of the element. Calling this method begins the measure pass of a layout cycle.

GetValue(BindableProperty) GetValue(BindableProperty)

Returns the value that is contained the BindableProperty.

(Inherited from BindableObject)
GetValues(BindableProperty, BindableProperty) GetValues(BindableProperty, BindableProperty)

For internal use by the Xamarin.Forms platform.

(Inherited from BindableObject)
GetValues(BindableProperty, BindableProperty, BindableProperty) GetValues(BindableProperty, BindableProperty, BindableProperty)

For internal use by the Xamarin.Forms platform.

(Inherited from BindableObject)
InvalidateMeasure() InvalidateMeasure()

Method that is called to invalidate the layout of this VisualElement. Raises the MeasureInvalidated event.

InvalidateMeasureNonVirtual(InvalidationTrigger) InvalidateMeasureNonVirtual(InvalidationTrigger)

For internal use by the Xamarin.Forms platform.

IsSet(BindableProperty) IsSet(BindableProperty)

Returns true if the target property exists and has been set.

(Inherited from BindableObject)
Layout(Rectangle) Layout(Rectangle)

Updates the bounds of the element during the layout cycle.

Measure(Double, Double, MeasureFlags) Measure(Double, Double, MeasureFlags)

Returns the minimum size that a visual element needs in order to be displayed on the device.

NativeSizeChanged() NativeSizeChanged()

For internal use by the Xamarin.Forms platform.

OnBindingContextChanged() OnBindingContextChanged()

Invoked whenever the binding context of the element changes. Implement this method to add class handling for this event.

(Inherited from Element)
OnChildAdded(Element) OnChildAdded(Element)

Application developers can override this method to respond when a child is added.

OnChildRemoved(Element) OnChildRemoved(Element)

Application developers can override this method to respond when a child is removed.

OnChildrenReordered() OnChildrenReordered()

Invoked whenever the ChildrenReordered event is about to be emitted. Implement this method to add class handling for this event.

OnMeasure(Double, Double) OnMeasure(Double, Double)

Method that is called when a layout measurement happens.

OnParentSet() OnParentSet()

Invoked whenever the Parent of an element is set. Implement this method in order to add behavior when the element is added to a parent.

OnPropertyChanged(String) OnPropertyChanged(String)

Method that is called when a bound property is changed.

(Inherited from Element)
OnPropertyChanging(String) 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) 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) OnSizeRequest(Double, Double)

This method is called during the measure pass of a layout cycle to get the desired size of an element.

OnTabIndexPropertyChanged(Int32, Int32) OnTabIndexPropertyChanged(Int32, Int32)
OnTabStopPropertyChanged(Boolean, Boolean) OnTabStopPropertyChanged(Boolean, Boolean)
RemoveBinding(BindableProperty) RemoveBinding(BindableProperty)

Removes a previously set binding.

(Inherited from BindableObject)
RemoveDynamicResource(BindableProperty) RemoveDynamicResource(BindableProperty)

Removes a previously set dynamic resource

(Inherited from Element)
SetBinding(BindableProperty, BindingBase) SetBinding(BindableProperty, BindingBase)

Assigns a binding to a property.

(Inherited from BindableObject)
SetDynamicResource(BindableProperty, String) 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) SetValue(BindableProperty, Object)

Sets the value of the specified property.

(Inherited from BindableObject)
SetValue(BindablePropertyKey, Object) SetValue(BindablePropertyKey, Object)

Sets the value of the propertyKey.

(Inherited from BindableObject)
SetValueCore(BindableProperty, Object, SetValueFlags) SetValueCore(BindableProperty, Object, SetValueFlags)

For internal use by the Xamarin.Forms platform.

(Inherited from BindableObject)
SetValueFromRenderer(BindableProperty, Object) SetValueFromRenderer(BindableProperty, Object)

For internal use by the Xamarin.Forms platform.

(Inherited from Element)
SetValueFromRenderer(BindablePropertyKey, Object) SetValueFromRenderer(BindablePropertyKey, Object)

For internal use by the Xamarin.Forms platform.

(Inherited from Element)
SizeAllocated(Double, Double) SizeAllocated(Double, Double)

SizeAllocated is called during a layout cycle to signal the start of a sub-tree layout.

TabIndexDefaultValueCreator() TabIndexDefaultValueCreator()
TabStopDefaultValueCreator() TabStopDefaultValueCreator()
UnapplyBindings() UnapplyBindings()

Unapplies all previously set bindings.

(Inherited from BindableObject)
Unfocus() Unfocus()

Unsets focus to this element.

Events

BatchCommitted BatchCommitted

For internal use by the Xamarin.Forms platform.

BindingContextChanged BindingContextChanged

Raised whenever the BindingContext property changes.

(Inherited from BindableObject)
ChildAdded ChildAdded

Occurs whenever a child element is added to the element.

(Inherited from Element)
ChildRemoved ChildRemoved

Occurs whenever a child element is removed from the element.

(Inherited from Element)
ChildrenReordered ChildrenReordered

Occurs when the Children of a VisualElement have been re-ordered.

DescendantAdded DescendantAdded

Occurs whenever a child element is added to the elements subtree.

(Inherited from Element)
DescendantRemoved DescendantRemoved

Occurs whenever a child element is removed from the elements subtree.

(Inherited from Element)
FocusChangeRequested FocusChangeRequested

For internal use by the Xamarin.Forms platform.

Focused Focused

Occurs when the element receives focus.

MeasureInvalidated MeasureInvalidated

Event that is raised when the layout of a visual element is invalidated.

PlatformSet PlatformSet

For internal use by the Xamarin.Forms platform.

(Inherited from Element)
PropertyChanged PropertyChanged

Raised when a property has changed.

(Inherited from BindableObject)
PropertyChanging PropertyChanging

Raised when a property is about to change.

(Inherited from BindableObject)
SizeChanged SizeChanged

Occurs when either the Width or the Height properties change value on this element.

Unfocused Unfocused

Occurs when the element loses focus.

Explicit Interface Implementations

IDynamicResourceHandler.SetDynamicResource(BindableProperty, String) IDynamicResourceHandler.SetDynamicResource(BindableProperty, String)

For internal use by the Xamarin.Forms platform.

(Inherited from BindableObject)
IElementController.SetValueFromRenderer(BindableProperty, Object) IElementController.SetValueFromRenderer(BindableProperty, Object)

For internal use by the Xamarin.Forms platform.

(Inherited from Element)
INameScope.RegisterName(String, Object) INameScope.RegisterName(String, Object)

For internal use only.

(Inherited from Element)
IVisualElementController.EffectiveFlowDirection 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) IVisualElementController.InvalidateMeasure(InvalidationTrigger)

This method is for internal use.

Extension Methods

AbortAnimation(IAnimatable, String) AbortAnimation(IAnimatable, String)

Stops the animation.

Animate(IAnimatable, String, Action<Double>, Double, Double, UInt32, UInt32, Easing, Action<Double,Boolean>, Func<Boolean>) Animate(IAnimatable, String, Action<Double>, Double, Double, UInt32, UInt32, Easing, Action<Double,Boolean>, Func<Boolean>)

Sets the specified parameters and starts the animation.

Animate(IAnimatable, String, Action<Double>, UInt32, UInt32, Easing, Action<Double,Boolean>, Func<Boolean>) Animate(IAnimatable, String, Action<Double>, UInt32, UInt32, Easing, Action<Double,Boolean>, Func<Boolean>)

Sets the specified parameters and starts the animation.

Animate(IAnimatable, String, Animation, UInt32, UInt32, Easing, Action<Double,Boolean>, Func<Boolean>) Animate(IAnimatable, String, Animation, UInt32, UInt32, Easing, Action<Double,Boolean>, Func<Boolean>)

Sets the specified parameters and starts the animation.

Animate<T>(IAnimatable, String, Func<Double,T>, Action<T>, UInt32, UInt32, Easing, Action<T,Boolean>, Func<Boolean>) Animate<T>(IAnimatable, String, Func<Double,T>, Action<T>, UInt32, UInt32, Easing, Action<T,Boolean>, Func<Boolean>)

Sets the specified parameters and starts the animation.

AnimateKinetic(IAnimatable, String, Func<Double,Double,Boolean>, Double, Double, Action) AnimateKinetic(IAnimatable, String, Func<Double,Double,Boolean>, Double, Double, Action)

Sets the specified parameters and starts the kinetic animation.

AnimationIsRunning(IAnimatable, String) AnimationIsRunning(IAnimatable, String)

Returns a Boolean value that indicates whether or not the animation that is specified by handle is running.

SetBinding(BindableObject, BindableProperty, String, BindingMode, IValueConverter, String) SetBinding(BindableObject, BindableProperty, String, BindingMode, IValueConverter, String)

Creates and applies a binding to a property.

SetBinding<TSource>(BindableObject, BindableProperty, Expression<Func<TSource,Object>>, BindingMode, IValueConverter, String) SetBinding<TSource>(BindableObject, BindableProperty, Expression<Func<TSource,Object>>, BindingMode, IValueConverter, String)

Creates and applies a binding from an expression.

GetGroup<TView,TItem>(TItem) GetGroup<TView,TItem>(TItem)

For internal use by platform renderers.

GetGroupHeaderContent<TView,TItem>(TItem) GetGroupHeaderContent<TView,TItem>(TItem)

For internal use by platform renderers.

GetIndex<TView,TItem>(TItem) GetIndex<TView,TItem>(TItem)

For internal use by platform renderers.

GetIsGroupHeader<TView,TItem>(TItem) GetIsGroupHeader<TView,TItem>(TItem)

For internal use by platform renderers.

SetIsGroupHeader<TView,TItem>(TItem, Boolean) SetIsGroupHeader<TView,TItem>(TItem, Boolean)

For internal use by platform renderers.

FindByName<T>(Element, String) FindByName<T>(Element, String)

Returns the instance of type T that has name name in the scope that includes element.

FindNextElement(VisualElement, Boolean, IDictionary<Int32,List<VisualElement>>, Int32) FindNextElement(VisualElement, Boolean, IDictionary<Int32,List<VisualElement>>, Int32)

Retrieves the next (or previous if = false) VisualElement within the tab group at [].

GetTabIndexesOnParentPage(VisualElement, Int32) GetTabIndexesOnParentPage(VisualElement, Int32)

Gets a dictionary mapping between index values and lists of VisualElement objects whose IsTabStop value is true.

FadeTo(VisualElement, Double, UInt32, Easing) FadeTo(VisualElement, Double, UInt32, Easing)

Returns a task that performs the fade that is described by the opacity, length, and easing parameters.

LayoutTo(VisualElement, Rectangle, UInt32, Easing) LayoutTo(VisualElement, Rectangle, UInt32, Easing)

Returns a task that eases the bounds of the VisualElement that is specified by the view to the rectangle that is specified by the bounds parameter.

RelRotateTo(VisualElement, Double, UInt32, Easing) RelRotateTo(VisualElement, Double, UInt32, Easing)

Rotates the VisualElement that is specified by view from its current rotation by drotation.

RelScaleTo(VisualElement, Double, UInt32, Easing) RelScaleTo(VisualElement, Double, UInt32, Easing)

Returns a task that scales the VisualElement that is specified by view from its current scale to dscale.

RotateTo(VisualElement, Double, UInt32, Easing) RotateTo(VisualElement, Double, UInt32, Easing)

Returns a task that performs the rotation that is described by the rotation, length, and easing parameters..

RotateXTo(VisualElement, Double, UInt32, Easing) RotateXTo(VisualElement, Double, UInt32, Easing)

Returns a task that skews the Y axis by opacity, taking time length and using easing.

RotateYTo(VisualElement, Double, UInt32, Easing) RotateYTo(VisualElement, Double, UInt32, Easing)

Returns a task that skews the X axis by opacity, taking time length and using easing.

ScaleTo(VisualElement, Double, UInt32, Easing) ScaleTo(VisualElement, Double, UInt32, Easing)

Returns a task that scales the VisualElement that is specified by view to the absolute scale factor scale.

TranslateTo(VisualElement, Double, Double, UInt32, Easing) TranslateTo(VisualElement, Double, Double, UInt32, Easing)

Animates an elements TranslationX and TranslationY properties from their current values to the new values. This ensures that the input layout is in the same position as the visual layout.

HasVisualStateGroups(VisualElement) HasVisualStateGroups(VisualElement)

Returns true if element has one or more visual state groups associated with it. Otherwise, returns false.

LoadFromXaml<TXaml>(TXaml, String) LoadFromXaml<TXaml>(TXaml, String)

Returns an initialized view by loading the specified xaml.

LoadFromXaml<TXaml>(TXaml, Type) LoadFromXaml<TXaml>(TXaml, Type)

Returns a TXaml with the properties that are defined in the application manifest for callingType.

Applies to