Class SfExpander

A class which is a container that provides a way to host a customizable header and content part as compound view. The content part gets expanded upon tapping the header part of the SfExpander.

Inheritance

System.Object

SfExpander

Implements

System.IDisposable

Namespace: Syncfusion.XForms.Expander

Assembly: Syncfusion.Expander.XForms.dll

Syntax

public class SfExpander : View, IDisposable, IParentThemeElement, IThemeElement

Remarks

The SfExpander contains header and content which is fully customizable. The header of SfExpander includes indicator icon that can be used to expand and collapse the content and able to customize it. Expand and collapse of the view is controlled by IsExpanded property.

Constructors

SfExpander()

Initializes a new instance of the SfExpander class.

Declaration

public SfExpander()

Fields

AnimationDurationProperty

Identifies the AnimationDuration bindable property.

Declaration

public static readonly BindableProperty AnimationDurationProperty

Field Value

Type
Xamarin.Forms.BindableProperty

AnimationEasingProperty

Identifies the AnimationEasing bindable property.

Declaration

public static readonly BindableProperty AnimationEasingProperty

Field Value

Type
Xamarin.Forms.BindableProperty

ContentProperty

Identifies the Content bindable property.

Declaration

public static readonly BindableProperty ContentProperty

Field Value

Type
Xamarin.Forms.BindableProperty

Remarks

This bindable property is read-only.

DynamicSizeModeProperty

Identifies the DynamicSizeMode bindable property.

Declaration

public static readonly BindableProperty DynamicSizeModeProperty

Field Value

Type
Xamarin.Forms.BindableProperty

HeaderBackgroundColorProperty

Identifies the HeaderBackgroundColor bindable property.

Declaration

public static readonly BindableProperty HeaderBackgroundColorProperty

Field Value

Type
Xamarin.Forms.BindableProperty

HeaderIconPositionProperty

Identifies the HeaderIconPosition bindable property.

Declaration

public static readonly BindableProperty HeaderIconPositionProperty

Field Value

Type
Xamarin.Forms.BindableProperty

Remarks

This bindable property is read-only.

HeaderProperty

Identifies the Header bindable property.

Declaration

public static readonly BindableProperty HeaderProperty

Field Value

Type
Xamarin.Forms.BindableProperty

Remarks

This bindable property is read-only.

IconColorProperty

Identifies the IconColor bindable property.

Declaration

public static readonly BindableProperty IconColorProperty

Field Value

Type
Xamarin.Forms.BindableProperty

IsExpandedProperty

Identifies the IsExpanded bindable property.

Declaration

public static readonly BindableProperty IsExpandedProperty

Field Value

Type
Xamarin.Forms.BindableProperty

Remarks

This bindable property is read-only.

Properties

AnimationDuration

Gets or sets the value indicates how long the animation cycle should take when expand and collapse the SfExpander.

Declaration

public double AnimationDuration { get; set; }

Property Value

Type	Description
System.Double	The value indicates how long the animation cycle should take when expand and collapse the SfExpander.

Remarks

By default, the animation duration is 200d.

Examples

expander.AnimationDuration = 100d;

AnimationEasing

Gets or sets the AnimationEasing that specifies the rate of change of parameter over time or animation style of the expander.

Declaration

public AnimationEasing AnimationEasing { get; set; }

Property Value

Type	Description
AnimationEasing	The type of animation that specifies the rate of change of parameter over time or animation style of the expander.

Remarks

Set this property as None to disable the animation for SfExpander.

Examples

expander.AnimationEasing = AnimationEasing.Linear;

Content

Gets or sets any kind of customizable visual element that can be loaded as content part of the SfExpander. The default value is null which displays an empty space when expanded.

Declaration

public View Content { get; set; }

Property Value

Type	Description
Xamarin.Forms.View	The view to be loaded as the expander part of the SfExpander.

Examples

var content = new Label();
content.Text = "SfExpander provides a way to add the content in an expandable area.";
expander.Content = content;

DynamicSizeMode

Gets or sets the value indicating whether to update expander based on dynamic size changes of Header view and Content view.

Declaration

public DynamicSizeMode DynamicSizeMode { get; set; }

Property Value

Type
DynamicSizeMode

Examples

expander.DynamicSizeMode = DynamicSizeMode.Content | DynamicSizeMode.Header;

Header

Gets or sets the view to be loaded as the header of the SfExpander. The header also contains the header view icon which is positioned based on the HeaderIconPosition property.

Declaration

public View Header { get; set; }

Property Value

Type	Description
Xamarin.Forms.View	The view to be loaded as the header of the SfExpander.

Remarks

The view to be loaded as the header of the SfExpander. Customize the header part of the control with any desired view or layout. The header contains the header icon view that is positioned based on the HeaderIconPosition property. Customize the header icon position with start, end and none values which is configured using IconPosition enum.

Examples

var header = new Label();
header.Text = DateTime.Now.ToString("hh:mm tt");
expander.Header = header;

HeaderBackgroundColor

Gets or sets the background color for the expander header item.

Declaration

public Color HeaderBackgroundColor { get; set; }

Property Value

Type
Xamarin.Forms.Color

Examples

expander.HeaderBackgroundColor = Color.Grey;

HeaderIconPosition

Gets or sets the IconPosition indicates that where to show the header view icon in the Header.

Declaration

public IconPosition HeaderIconPosition { get; set; }

Property Value

Type	Description
IconPosition	The position indicates that where to show the header view icon in the Header.

Examples

expander.HeaderIconPosition = IconPosition.End;

IconColor

Gets or sets the expander icon color.

Declaration

public Color IconColor { get; set; }

Property Value

Type
Xamarin.Forms.Color

Examples

expander.IconColor = Color.Grey;

IsExpanded

Gets or sets a value indicating whether the SfExpander is in Expanded state or Collapsed state.

Declaration

public bool IsExpanded { get; set; }

Property Value

Type	Description
System.Boolean	The boolean value indicating whether the SfExpander is in Expanded state or Collapsed state.

Examples

expander.IsExpanded = true;

Methods

ChangeVisualState()

Helps to trigger the VisualState initially when View is loaded.

Declaration

protected override void ChangeVisualState()

Dispose()

Perform final clean up before it is released from memory.

Declaration

public void Dispose()

Dispose(Boolean)

Releases the unmanaged resources used by the component and optionally releases the managed resources.

Declaration

protected virtual void Dispose(bool disposing)

Parameters

Type	Name	Description
System.Boolean	disposing	if true - release both managed and unmanaged resources; if false - release only unmanaged resources.

OnBindingContextChanged()

Notifies the change in BindingContext for the expander.

Declaration

protected override void OnBindingContextChanged()

OnSizeAllocated(Double, Double)

Allocates the size of item elements.

Declaration

protected override void OnSizeAllocated(double width, double height)

Parameters

Type	Name	Description
System.Double	width	The new width of the element.
System.Double	height	The new height of the element.

RaiseCollapsedEvent()

Raises the Collapsed event with ExpandedAndCollapsedEventArgs.

Declaration

protected void RaiseCollapsedEvent()

RaiseCollapsingEvent()

Raises the Collapsing event with ExpandingAndCollapsingEventArgs.

Declaration

protected bool RaiseCollapsingEvent()

Returns

Type	Description
System.Boolean	Returns true if collapsing event is not triggered else inverse of ExpandingAndCollapsingEventArgs.Cancel value.

See Also

System.ComponentModel.CancelEventArgs

RaiseExpandedEvent()

Raises the Expanded event with ExpandedAndCollapsedEventArgs.

Declaration

protected void RaiseExpandedEvent()

RaiseExpandingEvent()

Raises the Expanding event with ExpandingAndCollapsingEventArgs.

Declaration

protected bool RaiseExpandingEvent()

Returns

Type	Description
System.Boolean	Returns true if expanding event is not triggered else inverse of ExpandingAndCollapsingEventArgs.Cancel value.

See Also

System.ComponentModel.CancelEventArgs

Events

Collapsed

This event occurs after an SfExpander is collapsed when tapping on the Header.

Declaration

public event EventHandler<ExpandedAndCollapsedEventArgs> Collapsed

Event Type

Type
System.EventHandler<ExpandedAndCollapsedEventArgs>

Remarks

The event handler receives an argument of type ExpandingAndCollapsingEventArgs containing data related to this event.

Examples

expander.Collapsed += Expander_Collapsed;

private void Expander_Collapsed(object sender, ExpandedAndCollapsedEventArgs e)
{
    label.Text = "Burger and Pizza";
    expander.Header.BackgroundColor = Color.Aqua;
}

Collapsing

This event occurs while an SfExpander is collapsing when tapping on the Header. It is possible to cancel the collapsing action using the System.ComponentModel.CancelEventArgs.Cancel property in the event args.

Declaration

public event EventHandler<ExpandingAndCollapsingEventArgs> Collapsing

Event Type

Type
System.EventHandler<ExpandingAndCollapsingEventArgs>

Remarks

The user can control the expanding of content by using ExpandingAndCollapsingEventArgs of this event. If the Cancel property is set to true in the event's handler, the execution of the current event is cancelled.

Examples

expander.Collapsing += Expander_Collapsing;

private void Expander_Collapsing(object sender, ExpandingAndCollapsingEventArgs e)
{
    // Below code cancels the collapsing operation of the SfExpander control.
    e.Cancel = true;
}

Expanded

This event occurs after an SfExpander is expanded when tapping on the Header.

Declaration

public event EventHandler<ExpandedAndCollapsedEventArgs> Expanded

Event Type

Type
System.EventHandler<ExpandedAndCollapsedEventArgs>

Remarks

The event handler receives an argument of type ExpandingAndCollapsingEventArgs containing data related to this event.

Examples

expander.Expanded += Expander_Expanded;

private void Expander_Expanded(object sender, ExpandedAndCollapsedEventArgs e)
{
    label.Text = "Burger";
    expander.Header.BackgroundColor = Color.YellowGreen;
}

Expanding

This event occurs while an SfExpander is expanding when tapping on the Header. It is possible to cancel the expanding action using the System.ComponentModel.CancelEventArgs.Cancel property in the event args.

Declaration

public event EventHandler<ExpandingAndCollapsingEventArgs> Expanding

Event Type

Type
System.EventHandler<ExpandingAndCollapsingEventArgs>

Remarks

The user can control the expanding of content by using ExpandingAndCollapsingEventArgs of this event. If the Cancel property is set to true in the event's handler, the execution of the current event is cancelled.

Examples

expander.Expanding += Expander_Expanding;

private void Expander_Expanding(object sender, ExpandingAndCollapsingEventArgs e)
{
    // Below code cancels the expanding operation of the SfExpander control.
    e.Cancel = true;
}

Implements

System.IDisposable