Button Class
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
A button View that reacts to touch events.
[Xamarin.Forms.RenderWith(typeof(Xamarin.Forms.Platform._ButtonRenderer))]
public class Button : Xamarin.Forms.View, Xamarin.Forms.IBorderElement, Xamarin.Forms.IButtonController, Xamarin.Forms.IElementConfiguration<Xamarin.Forms.Button>, Xamarin.Forms.IImageController, Xamarin.Forms.IImageElement, Xamarin.Forms.Internals.IFontElementtype Button = class
inherit View
interface IFontElement
interface IBorderElement
interface IButtonController
interface IViewController
interface IVisualElementController
interface IElementController
interface IElementConfiguration<Button>
interface IImageController
interface IImageElement- Inheritance
- Attributes
- Implements
Remarks
Button Appearance
In addition to the appearance properties common to all View objects, the Button class provides the BorderColor, BorderWidth, BorderRadius, and Image properties.
The XAML code snippet below demonstrates how to use these properties to create a basic button with the text "Press me!" The image that the button displays appears on the start side of the layout, which is the left side for left-to-right languages.
<Button Text="Press me!"
Image="icon.png"
BackgroundColor="White"
BorderRadius="10"
BorderWidth="2"
BorderColor="Black"
HorizontalOptions="Center"/>
To display the icon.png image with the above XAML, the developer must place it in the appropriate location, with the appropriate build action, specific to each platform project. The Images topic explains this and other important details about working with images in Xamarin.Forms.
Button Events
Buttons notify the developer of press, release, and click events with the Pressed, Released, and Clicked events, respectively.
The following XAML assigns handlers to two of these button events:
<Button x:Name="PressMeButton"
Text="Press Me!"
Pressed="PressMeButton_Pressed"
Clicked="PressMeButton_Clicked"/>
With the XAML above, the following event handlers in the code-behind file change the button's text when these events are raised:
private void PressMeButton_Pressed(object sender, EventArgs e)
{
(sender as Button).Text = "You pressed me!";
}
private void PressMeButton_Clicked(object sender, EventArgs e)
{
(sender as Button).Text = "I was just clicked!";
}
Commands
The commanding API for buttons allows the developer to run a command in response to what would otherwise be the Clicked event.
The following XAML specifes a command to run when the button is clicked. The command updates a view model property called modelUpdateCount, which the button then uses to update its text. (The text binding is shown for completeness. Only the commanding code is relevant.):
<Button Text="{Binding modelUpdateCount, StringFormat='Number of updates to the model: {0:D}'}"
Command="{Binding IncrementLabelCommand}" />
With the XAML above, the developer first defines the IncrementLabelCommand property on the view model and implements a method with which to later instantiate the command:
public ICommand IncrementLabelCommand { get; private set; }
void IncrementLabel()
{
modelUpdateCount++;
}
Second, the developer initializes the command with the method (or action):
public ViewModelDemo()
{
IncrementLabelCommand = new Command(IncrementLabel);
}
Finally, the developer must sets the binding context in the constructor for the main page to that of the view model where the property is implemented:
public MainPage()
{
InitializeComponent();
BindingContext = new ViewModelDemo();
}
Constructors
| Button() |
Initializes a new instance of the Button class. |
Fields
| BorderColorProperty |
The backing store for the BorderColor bindable property. |
| BorderRadiusProperty |
Obsolete.
The backing store for the BorderRadius bindable property. |
| BorderWidthProperty |
The backing store for the BorderWidth bindable property. |
| CharacterSpacingProperty |
The backing store for the CharacterSpacing bindable property. |
| CommandParameterProperty |
The backing store for the CommandParameter bindable property. |
| CommandProperty |
The backing store for the Command bindable property. |
| ContentLayoutProperty |
The backing store for the ContentLayout bindable property. |
| CornerRadiusProperty |
The backing store for the CornerRadius bindable property. |
| FontAttributesProperty |
The backing store for the FontAttributes bindable property. |
| FontFamilyProperty |
The backing store for the FontFamily bindable property. |
| FontProperty |
The backing store for the Font bindable property. |
| FontSizeProperty |
The backing store for the FontSize bindable property. |
| ImageProperty |
Obsolete.
The backing store for the Image bindable property. |
| ImageSourceProperty |
The backing store for the ImageSource bindable property. |
| IsPressedProperty |
The backing store for the IsPressed bindable property. |
| PaddingProperty |
The backing store for the Padding bindable property. |
| TextColorProperty |
The backing store for the TextColor bindable property. |
| TextProperty |
The backing store for the Text bindable property. |
| TextTransformProperty |
The backing store for the TextTransform 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. (Inherited from VisualElement) |
| 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. (Inherited from VisualElement) |
| AutomationId |
Gets or sets a value that allows the automation framework to find and interact with this element. (Inherited from Element) |
| Background | (Inherited from VisualElement) |
| BackgroundColor |
Gets or sets the color which will fill the background of a VisualElement. This is a bindable property. (Inherited from VisualElement) |
| Batched |
For internal use by the Xamarin.Forms platform. (Inherited from VisualElement) |
| Behaviors |
Gets the list of Behaviors associated to this element. This is a bindable property. (Inherited from VisualElement) |
| 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) |
| BorderColor |
Gets or sets a color that describes the border stroke color of the button. This is a bindable property. |
| BorderRadius |
Obsolete.
Gets or sets the corner radius of the border. This is a bindable property. |
| BorderWidth |
Gets or sets the width of the border. This is a bindable property. |
| Bounds |
Gets the bounds of the element. (Inherited from VisualElement) |
| CharacterSpacing | |
| class | (Inherited from NavigableElement) |
| ClassId |
Gets or sets a value used to identify a collection of semantically similar elements. (Inherited from Element) |
| Clip | (Inherited from VisualElement) |
| Command |
Gets or sets the command to invoke when the button is activated. This is a bindable property. |
| CommandParameter |
Gets or sets the parameter to pass to the Command property. This is a bindable property. |
| ContentLayout |
Gets or sets an object that controls the position of the button image and the spacing between the button's image and the button's text. |
| CornerRadius |
Gets or sets the corner radius for the button, in device-independent units. |
| DisableLayout |
For internal use by the Xamarin.Forms platform. (Inherited from VisualElement) |
| 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. (Inherited from VisualElement) |
| Font |
Gets or sets the Font for the Label text. This is a bindable property. |
| FontAttributes |
Gets a value that indicates whether the font for the button text is bold, italic, or neither. |
| FontFamily |
Gets the font family to which the font for the button text belongs. |
| FontSize |
Gets or sets the size of the font of the button text. |
| GestureController |
Gets the gesture controller for the view. (Inherited from View) |
| GestureRecognizers |
The collection of gesture recognizers associated with this view. (Inherited from View) |
| Height |
Gets the current rendered height of this element. This is a read-only bindable property. (Inherited from VisualElement) |
| HeightRequest |
Gets or sets the desired height override of this element. (Inherited from VisualElement) |
| HorizontalOptions |
Gets or sets the LayoutOptions that define how the element gets laid in a layout cycle. This is a bindable property. (Inherited from View) |
| Id |
Gets a value that can be used to uniquely identify an element through the run of an application. (Inherited from Element) |
| Image |
Obsolete.
Gets or sets the optional image source to display next to the text in the Button. This is a bindable property. |
| ImageSource |
Allows you to display a bitmap image on the Button. |
| InputTransparent |
Gets or sets a value indicating whether this element should be involved in the user interaction cycle. This is a bindable property. (Inherited from VisualElement) |
| IsEnabled |
Gets or sets a value indicating whether this element is enabled in the user interface. This is a bindable property. (Inherited from VisualElement) |
| IsFocused |
Gets a value indicating whether this element is focused currently. This is a bindable property. (Inherited from VisualElement) |
| IsInNativeLayout |
For internal use by the Xamarin.Forms platform. (Inherited from VisualElement) |
| IsNativeStateConsistent |
For internal use by the Xamarin.Forms platform. (Inherited from VisualElement) |
| IsPlatformEnabled |
For internal use by the Xamarin.Forms platform. (Inherited from VisualElement) |
| IsPressed |
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. (Inherited from VisualElement) |
| 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. (Inherited from VisualElement) |
| LogicalChildren |
For internal use by the Xamarin.Forms platform. (Inherited from Element) |
| Margin |
Gets or sets the margin for the view. (Inherited from View) |
| MinimumHeightRequest |
Gets or sets a value which overrides the minimum height the element will request during layout. (Inherited from VisualElement) |
| MinimumWidthRequest |
Gets or sets a value which overrides the minimum width the element will request during layout. (Inherited from VisualElement) |
| 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. (Inherited from VisualElement) |
| Padding |
Gets or sets the padding for the button. |
| 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. (Inherited from VisualElement) |
| Rotation |
Gets or sets the rotation (in degrees) about the Z-axis (affine rotation) when the element is rendered. (Inherited from VisualElement) |
| RotationX |
Gets or sets the rotation (in degrees) about the X-axis (perspective rotation) when the element is rendered. (Inherited from VisualElement) |
| RotationY |
Gets or sets the rotation (in degrees) about the Y-axis (perspective rotation) when the element is rendered. (Inherited from VisualElement) |
| Scale |
Gets or sets the scale factor applied to the element. (Inherited from VisualElement) |
| ScaleX |
Gets or sets a scale value to apply to the X direction. (Inherited from VisualElement) |
| ScaleY |
Gets or sets a scale value to apply to the Y direction. (Inherited from VisualElement) |
| 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 | (Inherited from VisualElement) |
| Text |
Gets or sets the Text displayed as the content of the button. This is a bindable property. |
| TextColor |
Gets or sets the Color for the text of the button. This is a bindable property. |
| TextTransform | |
| TranslationX |
Gets or sets the X translation delta of the element. (Inherited from VisualElement) |
| TranslationY |
Gets or sets the Y translation delta of the element. (Inherited from VisualElement) |
| Triggers |
Gets the list of Trigger associated to this element. This is a bindable property. (Inherited from VisualElement) |
| VerticalOptions |
Gets or sets the LayoutOptions that define how the element gets laid in a layout cycle. This is a bindable property. (Inherited from View) |
| Visual | (Inherited from VisualElement) |
| Width |
Gets the current rendered width of this element. This is a read-only bindable property. (Inherited from VisualElement) |
| WidthRequest |
Gets or sets the desired width override of this element. (Inherited from VisualElement) |
| X |
Gets the current X position of this element. This is a read-only bindable property. (Inherited from VisualElement) |
| Y |
Gets the current Y position of this element. This is a read-only bindable property. (Inherited from VisualElement) |
Methods
| ApplyBindings() |
Apply the bindings to BindingContext. (Inherited from BindableObject) |
| BatchBegin() |
Signals the start of a batch of changes to the elements properties. (Inherited from VisualElement) |
| BatchCommit() |
Signals the end of a batch of commands to the element and that those commands should now be committed. (Inherited from VisualElement) |
| 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. (Inherited from VisualElement) |
| GetChildElements(Point) |
Returns the child elements that are visually beneath the specified |
| GetSizeRequest(Double, Double) |
Obsolete.
Returns the SizeRequest of the element. Calling this method begins the measure pass of a layout cycle. (Inherited from VisualElement) |
| 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. (Inherited from VisualElement) |
| InvalidateMeasureNonVirtual(InvalidationTrigger) |
For internal use by the Xamarin.Forms platform. (Inherited from VisualElement) |
| IsSet(BindableProperty) |
Returns |
| Layout(Rectangle) |
Updates the bounds of the element during the layout cycle. (Inherited from VisualElement) |
| Measure(Double, Double, MeasureFlags) |
Returns the minimum size that a visual element needs in order to be displayed on the device. (Inherited from VisualElement) |
| NativeSizeChanged() |
For internal use by the Xamarin.Forms platform. (Inherited from VisualElement) |
| On<T>() |
Returns the platform-specific instance of this Button, on which a platform-specific method may be called. |
| OnBindingContextChanged() |
Method that is raised when the binding context changes. |
| OnChildAdded(Element) |
Application developers can override this method to respond when a child is added. (Inherited from VisualElement) |
| OnChildRemoved(Element, Int32) | (Inherited from VisualElement) |
| OnChildRemoved(Element) |
Obsolete.
Application developers can override this method to respond when a child is removed. (Inherited from VisualElement) |
| OnChildrenReordered() |
Invoked whenever the ChildrenReordered event is about to be emitted. Implement this method to add class handling for this event. (Inherited from VisualElement) |
| OnMeasure(Double, Double) |
Method that is called when a layout measurement happens. (Inherited from VisualElement) |
| 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. (Inherited from VisualElement) |
| OnSizeRequest(Double, Double) |
Obsolete.
This method is called during the measure pass of a layout cycle to get the desired size of an element. (Inherited from VisualElement) |
| OnTabIndexPropertyChanged(Int32, Int32) | (Inherited from VisualElement) |
| OnTabStopPropertyChanged(Boolean, Boolean) | (Inherited from VisualElement) |
| RemoveBinding(BindableProperty) |
Removes a previously set binding. (Inherited from BindableObject) |
| RemoveDynamicResource(BindableProperty) |
Removes a previously set dynamic resource (Inherited from Element) |
| SendClicked() |
For internal use by the Xamarin.Forms platform. |
| SendPressed() |
For internal use by the Xamarin.Forms platform. |
| SendReleased() |
For internal use by the Xamarin.Forms platform. |
| 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. (Inherited from VisualElement) |
| TabIndexDefaultValueCreator() | (Inherited from VisualElement) |
| TabStopDefaultValueCreator() | (Inherited from VisualElement) |
| UnapplyBindings() |
Unapplies all previously set bindings. (Inherited from BindableObject) |
| Unfocus() |
Unsets focus to this element. (Inherited from VisualElement) |
| UpdateFormsText(String, TextTransform) | |
Events
| BatchCommitted |
For internal use by the Xamarin.Forms platform. (Inherited from VisualElement) |
| 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. (Inherited from VisualElement) |
| Clicked |
Occurs when the Button is clicked. |
| 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. (Inherited from VisualElement) |
| Focused |
Occurs when the element receives focus. (Inherited from VisualElement) |
| MeasureInvalidated |
Event that is raised when the layout of a visual element is invalidated. (Inherited from VisualElement) |
| PlatformSet |
Obsolete.
(Inherited from Element)
|
| Pressed |
Occurs when the Button is pressed. |
| PropertyChanged |
Raised when a property has changed. (Inherited from BindableObject) |
| PropertyChanging |
Raised when a property is about to change. (Inherited from BindableObject) |
| Released |
Occurs when the Button is released. |
| SizeChanged |
Occurs when either the Width or the Height properties change value on this element. (Inherited from VisualElement) |
| Unfocused |
Occurs when the element loses focus. (Inherited from VisualElement) |
Explicit Interface Implementations
| IBorderElement.BorderColorDefaultValue |
For internal use by the Xamarin.Forms platform. |
| IBorderElement.BorderWidthDefaultValue |
For internal use by the Xamarin.Forms platform. |
| IBorderElement.CornerRadiusDefaultValue |
For internal use by the Xamarin.Forms platform. |
| IBorderElement.IsBackgroundColorSet() |
For internal use by the Xamarin.Forms platform. |
| IBorderElement.IsBackgroundSet() | |
| IBorderElement.IsBorderColorSet() |
For internal use by the Xamarin.Forms platform. |
| IBorderElement.IsBorderWidthSet() |
For internal use by the Xamarin.Forms platform.. |
| IBorderElement.IsCornerRadiusSet() |
For internal use by the Xamarin.Forms platform. |
| IBorderElement.OnBorderColorPropertyChanged(Color, Color) |
For internal use by the Xamarin.Forms platform. |
| 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) |
| IFontElement.FontSizeDefaultValueCreator() |
For internal use by the Xamarin.Forms platform. |
| IFontElement.OnFontAttributesChanged(FontAttributes, FontAttributes) |
For internal use by the Xamarin.Forms platform. |
| IFontElement.OnFontChanged(Font, Font) |
For internal use by the Xamarin.Forms platform. |
| IFontElement.OnFontFamilyChanged(String, String) |
For internal use by the Xamarin.Forms platform. |
| IFontElement.OnFontSizeChanged(Double, Double) |
For internal use by the Xamarin.Forms platform. |
| IGestureController.CompositeGestureRecognizers |
For internal use by the Xamarin.Forms platform. (Inherited from View) |
| IImageController.GetLoadAsAnimation() | |
| IImageController.SetIsLoading(Boolean) |
For internal use by the Xamarin.Forms platform. |
| IImageElement.Aspect |
For internal use by the Xamarin.Forms platform. |
| IImageElement.IsAnimationPlaying | |
| IImageElement.IsLoading | |
| IImageElement.IsOpaque |
For internal use by the Xamarin.Forms platform. |
| IImageElement.OnImageSourceSourceChanged(Object, EventArgs) | |
| IImageElement.RaiseImageSourcePropertyChanged() |
For internal use by the Xamarin.Forms platform. |
| IImageElement.Source |
For internal use by the Xamarin.Forms platform. |
| 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. (Inherited from VisualElement) |
| IVisualElementController.InvalidateMeasure(InvalidationTrigger) |
This method is for internal use. (Inherited from VisualElement) |