Picker Class

Definition

A View control for picking an element in a list.

[Xamarin.Forms.RenderWith(typeof(Xamarin.Forms.Platform._PickerRenderer))]
public class Picker : Xamarin.Forms.View, Xamarin.Forms.IElementConfiguration<Xamarin.Forms.Picker>, Xamarin.Forms.Internals.IFontElement
type Picker = class
    inherit View
    interface IFontElement
    interface IElementConfiguration<Picker>
Inheritance
Attributes
Implements

Remarks

The visual representation of a Picker is similar to a Entry, but a picker control appears in place of a keyboard.

The following example shows the creation of a Picker.

using System;
using System.Collections.Generic;
using Xamarin.Forms;

namespace FormsGallery
{
    class PickerDemoPage : ContentPage
    {
        // Dictionary to get Color from color name.
        Dictionary<string, Color> nameToColor = new Dictionary<string, Color>
        {
            { "Aqua", Color.Aqua }, { "Black", Color.Black },
            { "Blue", Color.Blue }, { "Fuchsia", Color.Fuchsia },
            { "Gray", Color.Gray }, { "Green", Color.Green },
            { "Lime", Color.Lime }, { "Maroon", Color.Maroon },
            { "Navy", Color.Navy }, { "Olive", Color.Olive },
            { "Purple", Color.Purple }, { "Red", Color.Red },
            { "Silver", Color.Silver }, { "Teal", Color.Teal },
            { "White", Color.White }, { "Yellow", Color.Yellow }
        };

        public PickerDemoPage()
        {
            Label header = new Label
            {
                Text = "Picker",
                FontSize = Device.GetNamedSize (NamedSize.Large, typeof(Label)),
                HorizontalOptions = LayoutOptions.Center
            };

            Picker picker = new Picker
            {
                Title = "Color",
                VerticalOptions = LayoutOptions.CenterAndExpand
            };

            foreach (string colorName in nameToColor.Keys)
            {
                picker.Items.Add(colorName);
            }

            // Create BoxView for displaying picked Color
            BoxView boxView = new BoxView
            {
                WidthRequest = 150,
                HeightRequest = 150,
                HorizontalOptions = LayoutOptions.Center,
                VerticalOptions = LayoutOptions.CenterAndExpand
            };

            picker.SelectedIndexChanged += (sender, args) =>
                {
                    if (picker.SelectedIndex == -1)
                    {
                        boxView.Color = Color.Default;
                    }
                    else
                    {
                        string colorName = picker.Items[picker.SelectedIndex];
                        boxView.Color = nameToColor[colorName];
                    }
                };

            // Accomodate iPhone status bar.
            this.Padding = new Thickness(10, Device.OnPlatform(20, 0, 0), 10, 5);

            // Build the page.
            this.Content = new StackLayout
            {
                Children =
                {
                    header,
                    picker,
                    boxView
                }
            };

        }
    }
}

Constructors

Picker()

Initializes a new instance of the Picker class.

Fields

CharacterSpacingProperty
FontAttributesProperty

Backing store for the FontAttributes property.

FontFamilyProperty

Backing store for the FontFamily property.

FontSizeProperty

Backing store for the FontSize property.

HorizontalTextAlignmentProperty
ItemsSourceProperty

Backing store for the ItemsSource property.

SelectedIndexProperty

Backing store for the SelectedIndex bindable property.

SelectedItemProperty

Backing store for the SelectedItem property.

TextColorProperty

Backing store for the TextColor property.

TextTransformProperty
TitleColorProperty

The backing store for the TitleColor field.

TitleProperty

Backing store for the Title bindable property.

VerticalTextAlignmentProperty

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)
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)
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)
FontAttributes

Gets a value that indicates whether the font for the searchbar text is bold, italic, or neither.

FontFamily

Gets or sets the font family for the picker text.

FontSize

Gets or sets the size of the font for the text in the picker.

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)
HorizontalTextAlignment
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.

(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)
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)
ItemDisplayBinding

Gets or sets a binding that selects the property that will be displayed for each object in the list of items.

Items

Gets the list of choices.

ItemsSource

Gets or sets the source list of items to template and display.

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)
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)
SelectedIndex

Gets or sets the index of the selected item of the picker. This is a bindable property.

SelectedItem

Gets or sets the selected item.

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)
TextColor

Gets or sets the text color.

TextTransform
Title

Gets or sets the title for the Picker. This is a bindable property.

TitleColor
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)
VerticalTextAlignment
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.

(Inherited from VisualElement)
ClearValue(BindableProperty)

Clears any value set by SetValue for property.

(Inherited from BindableObject)
ClearValue(BindablePropertyKey)

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

(Inherited from BindableObject)
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 point.

(Inherited from View)
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)
Obsolete.

For internal use by the Xamarin.Forms platform.

(Inherited from BindableObject)
GetValues(BindableProperty, 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 true if the target property exists and has been set.

(Inherited from BindableObject)
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 Picker, on which a platform-specific method may be called.

OnBindingContextChanged()

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

(Inherited from View)
OnChildAdded(Element)

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

(Inherited from VisualElement)
OnChildRemoved(Element)
Obsolete.

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

(Inherited from VisualElement)
OnChildRemoved(Element, Int32) (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)
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)
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)
PropertyChanged

Raised when a property has changed.

(Inherited from BindableObject)
PropertyChanging

Raised when a property is about to change.

(Inherited from BindableObject)
SelectedIndexChanged

Raised when the value of the SelectIndex property has changed.

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

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)
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)

Extension Methods

AbortAnimation(IAnimatable, String)

Stops the animation.

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>)

Sets the specified parameters and starts the animation.

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>)

Sets the specified parameters and starts the animation.

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

Sets the specified parameters and starts the kinetic animation.

AnimationIsRunning(IAnimatable, String)

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

Batch(IAnimatable)
GetPropertyIfSet<T>(BindableObject, BindableProperty, T)
SetAppThemeColor(BindableObject, BindableProperty, Color, Color)
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)
Obsolete.

Creates and applies a binding from an expression.

SetOnAppTheme<T>(BindableObject, BindableProperty, T, T)
FindByName<T>(Element, String)

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

FindNextElement(ITabStopElement, Boolean, IDictionary<Int32,List<ITabStopElement>>, Int32)
GetSortedTabIndexesOnParentPage(VisualElement)
GetTabIndexesOnParentPage(ITabStopElement, Int32)
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)

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)

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

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)

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

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)

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

ScaleTo(VisualElement, Double, UInt32, Easing)

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

ScaleXTo(VisualElement, Double, UInt32, Easing)
ScaleYTo(VisualElement, 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)

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

Applies to