Class Scroller

The Scroller is a container that holds and clips a single object and allows you to scroll across it.

Inheritance
Object
EvasObject
AccessibleObject
Widget
Container
Layout
Scroller
CircleScroller
Implements
Inherited Members
Namespace: ElmSharp
Assembly: ElmSharp.dll
Syntax
public class Scroller : Layout, IAccessibleObject

Constructors

Scroller()

Creates and initializes a new instance of the Scroller class.

Declaration
public Scroller()
API Version
preview

Scroller(EvasObject)

Creates and initializes a new instance of the Scroller class.

Declaration
public Scroller(EvasObject parent)
Parameters
Type Name Description
EvasObject parent

The EvasObject to which the new Scroller will be attached as a child.
API Version
preview

Properties

ChildHeight

Gets the height of the content object of the scroller.

Declaration
public int ChildHeight { get; }
Property Value
Type Description
Int32
API Version
preview

ChildWidth

Gets the width of the content object of the scroller.

Declaration
public int ChildWidth { get; }
Property Value
Type Description
Int32
API Version
preview

ContentPropagateEvents

Gets or sets the event propagation for a scroller. This enables or disables event propagation from the scroller content to the scroller and its parent. By default, event propagation is enabled.

Declaration
public bool ContentPropagateEvents { get; set; }
Property Value
Type Description
Boolean
API Version
preview

CurrentRegion

Gets the current region in the content object that is visible through the scroller.

Declaration
public Rect CurrentRegion { get; }
Property Value
Type Description
Rect
API Version
preview

HorizontalBounce

Sets or gets the horizontal bounce behaviour. When scrolling, the scroller may "bounce" when reaching an edge of the content object. This is a visual way to indicate the end has been reached. This is enabled by default for both axis. This API will set if it is enabled for the given axis with the boolean parameters for each axis.

Declaration
public bool HorizontalBounce { get; set; }
Property Value
Type Description
Boolean
API Version
preview

HorizontalGravity

Sets the scrolling gravity values for a scroller. The gravity defines how the scroller will adjust its view when the size of the scroller contents increase. The scroller will adjust the view to glue itself as follows: x=0.0, for staying where it is relative to the left edge of the content, x=1.0, for staying where it is relative to the rigth edge of the content, y=0.0, for staying where it is relative to the top edge of the content, y=1.0, for staying where it is relative to the bottom edge of the content. Default values for x and y are 0.0.

Declaration
public double HorizontalGravity { get; set; }
Property Value
Type Description
Double
API Version
preview

HorizontalLoop

Sets an infinite loop_ for a scroller. This function sets the infinite loop horizontally. If the content is set, it will be shown repeatedly.

Declaration
public bool HorizontalLoop { get; set; }
Property Value
Type Description
Boolean
API Version
preview

HorizontalPageIndex

Sets or gets the scroll current page number.

Declaration
public int HorizontalPageIndex { get; }
Property Value
Type Description
Int32
Remarks

Current page means the page which meets the left of the viewport. If there are two or more pages in the viewport, it returns the number of the page which meets the left of the viewport. The page number starts from 0. 0 is the first page.

API Version
preview

HorizontalPageScrollLimit

Sets or gets the maximum limit of the movable page at horizontal direction.

Declaration
public int HorizontalPageScrollLimit { get; set; }
Property Value
Type Description
Int32
API Version
preview

HorizontalRelativePageSize

Gets or sets a given scroller widget's scrolling page size, relative to its viewport size.

Declaration
public double HorizontalRelativePageSize { get; set; }
Property Value
Type Description
Double
API Version
preview

HorizontalScrollBarVisiblePolicy

Sets or gets the value of HorizontalScrollBarVisiblePolicy.

Declaration
public virtual ScrollBarVisiblePolicy HorizontalScrollBarVisiblePolicy { get; set; }
Property Value
Type Description
ScrollBarVisiblePolicy
Remarks

ScrollBarVisiblePolicy.Auto means the horizontal scrollbar is made visible if it is needed, and otherwise kept hidden. ScrollBarVisiblePolicy.Visible turns it on all the time, and ScrollBarVisiblePolicy.Invisible always keeps it off.

API Version
preview

HorizontalSnap

Gets or sets the page snapping behavior of a scroller.

Declaration
public bool HorizontalSnap { get; set; }
Property Value
Type Description
Boolean
Remarks

When scrolling, if a scroller is paged (see HorizontalRelativePageSize), the scroller may snap to pages when being scrolled, i.e., even if it had momentum to scroll further, it will stop at the next page boundaries. This is disabled, by default, for both axis. This function will set if it that is enabled or not, for each axis.

API Version
preview

HorizontalStepSize

Gets or sets the step size to move scroller by key event.

Declaration
public int HorizontalStepSize { get; set; }
Property Value
Type Description
Int32
API Version
preview

LastHorizontalPageNumber

Gets the scroll last page number. The page number starts from 0. 0 is the first page. This returns the last page number among the pages.

Declaration
public int LastHorizontalPageNumber { get; }
Property Value
Type Description
Int32
API Version
preview

LastVerticalPageNumber

Gets the scroll last page number. The page number starts from 0. 0 is the first page. This returns the last page number among the pages.

Declaration
public int LastVerticalPageNumber { get; }
Property Value
Type Description
Int32
API Version
preview

PageHeight

Gets or sets the page size to an absolute fixed value, with 0 turning it off for that axis.

Declaration
public int PageHeight { get; set; }
Property Value
Type Description
Int32
API Version
preview

PageWidth

Gets or sets the page size to an absolute fixed value, with 0 turning it off for that axis.

Declaration
public int PageWidth { get; set; }
Property Value
Type Description
Int32
API Version
preview

ScrollBlock

Sets or gets the value of ScrollBlock.

Declaration
public ScrollBlock ScrollBlock { get; set; }
Property Value
Type Description
ScrollBlock
Remarks

This function will block scrolling movement in a given direction. One can disable movements in the X-axis, the Y-axis, or both. The default value is ScrollBlock.None, where movements are allowed in both directions.

API Version
preview

SingleDirection

Gets or sets the type of single direction scroll.

Declaration
public ScrollSingleDirection SingleDirection { get; set; }
Property Value
Type Description
ScrollSingleDirection
API Version
preview

VerticalBounce

Sets or gets the vertical bounce behaviour. When scrolling, the scroller may "bounce" when reaching an edge of the content object. This is a visual way to indicate the end has been reached. This is enabled by default for both axis. This API will set if it is enabled for the given axis with the boolean parameters for each axis.

Declaration
public bool VerticalBounce { get; set; }
Property Value
Type Description
Boolean
API Version
preview

VerticalGravity

Sets the scrolling gravity values for a scroller. The gravity defines how the scroller will adjust its view when the size of the scroller contents increase. The scroller will adjust the view to glue itself as follows: x=0.0, for staying where it is relative to the left edge of the content, x=1.0, for staying where it is relative to the rigth edge of the content, y=0.0, for staying where it is relative to the top edge of the content, y=1.0, for staying where it is relative to the bottom edge of the content. Default values for x and y are 0.0.

Declaration
public double VerticalGravity { get; set; }
Property Value
Type Description
Double
API Version
preview

VerticalLoop

Sets an infinite loop_ for a scroller. This function sets the infinite loop vertically. If the content is set, it will be shown repeatedly.

Declaration
public bool VerticalLoop { get; set; }
Property Value
Type Description
Boolean
API Version
preview

VerticalPageIndex

Sets or gets the scroll current page number.

Declaration
public int VerticalPageIndex { get; }
Property Value
Type Description
Int32
Remarks

Current page means the page which meets the top of the viewport. If there are two or more pages in the viewport, it returns the number of the page which meets the top of the viewport. The page number starts from 0. 0 is the first page.

API Version
preview

VerticalPageScrollLimit

Sets or gets the maximum limit of the movable page at vertical direction.

Declaration
public int VerticalPageScrollLimit { get; set; }
Property Value
Type Description
Int32
API Version
preview

VerticalRelativePageSize

Gets or sets a given scroller widget's scrolling page size, relative to its viewport size.

Declaration
public double VerticalRelativePageSize { get; set; }
Property Value
Type Description
Double
API Version
preview

VerticalScrollBarVisiblePolicy

Sets or gets the value of VerticalScrollBarVisiblePolicy.

Declaration
public virtual ScrollBarVisiblePolicy VerticalScrollBarVisiblePolicy { get; set; }
Property Value
Type Description
ScrollBarVisiblePolicy
Remarks

ScrollBarVisiblePolicy.Auto means the vertical scrollbar is made visible if it is needed, and otherwise kept hidden. ScrollBarVisiblePolicy.Visible turns it on all the time, and ScrollBarVisiblePolicy.Invisible always keeps it off.

API Version
preview

VerticalSnap

Gets or sets the page snapping behavior of a scroller.

Declaration
public bool VerticalSnap { get; set; }
Property Value
Type Description
Boolean
Remarks

When scrolling, if a scroller is paged (see VerticalRelativePageSize), the scroller may snap to pages when being scrolled, i.e., even if it had momentum to scroll further, it will stop at the next page boundaries. This is disabled, by default, for both axis. This function will set if it that is enabled or not, for each axis.

API Version
preview

VerticalStepSize

Gets or sets the step size to move scroller by key event.

Declaration
public int VerticalStepSize { get; set; }
Property Value
Type Description
Int32
API Version
preview

WheelDisabled

Gets or sets a value whether mouse wheel is enabled or not over the scroller.

Declaration
public bool WheelDisabled { get; set; }
Property Value
Type Description
Boolean
API Version
preview

Methods

CreateHandle(EvasObject)

Creates a widget handle.

Declaration
protected override IntPtr CreateHandle(EvasObject parent)
Parameters
Type Name Description
EvasObject parent

Parent EvasObject.
Returns
Type Description
IntPtr

Handle IntPtr.
Overrides
API Version
preview

MinimumLimit(Boolean, Boolean)

Sets the scroller minimum size limited to the minimum size of the content. By default, the scroller will be as small as its design allows, irrespective of its content. This will make the scroller minimum size the right size horizontally and/or vertically to perfectly fit its content in that direction.

Declaration
public void MinimumLimit(bool horizontal, bool vertical)
Parameters
Type Name Description
Boolean horizontal

Enable limiting minimum size horizontally.
Boolean vertical

Enable limiting minimum size vertically.
API Version
preview

OnRealized()

The callback of the Realized event.

Declaration
protected override void OnRealized()
Overrides
API Version
preview

ScrollTo(Rect, Boolean)

Shows a specific virtual region within the scroller content object.

Declaration
public void ScrollTo(Rect region, bool animated)
Parameters
Type Name Description
Rect region

Rect struct of region.
Boolean animated

True means allows the scroller to "smoothly slide" to this location.
Remarks

This ensures that all (or part, if it does not fit) of the designated region in the virtual content object ((0, 0) starting at the top-left of the virtual content object) is shown within the scroller. If set "animated" to true, it will allows the scroller to "smoothly slide" to this location (if configuration in general calls for transitions). It may not jump immediately to the new location and may take a while and show other content along the way.

API Version
preview

ScrollTo(Int32, Int32, Boolean)

Shows a specific virtual region within the scroller content object by the page number. (0, 0) of the indicated page is located at the top-left corner of the viewport.

Declaration
public void ScrollTo(int horizontalPageIndex, int verticalPageIndex, bool animated)
Parameters
Type Name Description
Int32 horizontalPageIndex

The horizontal page number.
Int32 verticalPageIndex

The vertical page number.
Boolean animated

True means slider with animation.
API Version
preview

SetPageSize(Double, Double)

Sets the scroll page size relative to the viewport size.

Declaration
public void SetPageSize(double width, double height)
Parameters
Type Name Description
Double width

The horizontal page relative size.
Double height

The vertical page relative size.
Remarks

The scroller is capable of limiting scrolling by the user to "pages". That is to jump by and only show a "whole page" at a time as if the continuous area of the scroller content is split into page sized pieces. This sets the size of a page relative to the viewport of the scroller. 1.0 is "1 viewport" which is the size (horizontally or vertically). 0.0 turns it off in that axis. This is mutually exclusive with the page size (see elm_scroller_page_size_set() for more information). Likewise 0.5 is "half a viewport". Usable values are normally between 0.0 and 1.0 including 1.0. If you only want 1 axis to be page "limited", use 0.0 for the other axis.

API Version
preview

SetPageSize(Int32, Int32)

Sets the page size to an absolute fixed value, with 0 turning it off for that axis.

Declaration
public void SetPageSize(int width, int height)
Parameters
Type Name Description
Int32 width

The horizontal page size.
Int32 height

The vertical page size.
API Version
preview

Events

DragStart

DragStart will be triggered when dragging the contents around has started.

Declaration
public event EventHandler DragStart
Event Type
Type Description
EventHandler
API Version
preview

DragStop

DragStop will be triggered when dragging the contents around has stopped.

Declaration
public event EventHandler DragStop
Event Type
Type Description
EventHandler
API Version
preview

PageScrolled

PageScrolled will be triggered when the visible page has changed.

Declaration
public event EventHandler PageScrolled
Event Type
Type Description
EventHandler
API Version
preview

ScrollAnimationStarted

ScrollAnimationStarted will be triggered when the content animation has been started.

Declaration
public event EventHandler ScrollAnimationStarted
Event Type
Type Description
EventHandler
API Version
preview

ScrollAnimationStopped

ScrollAnimationStopped will be triggered when the content animation has been stopped.

Declaration
public event EventHandler ScrollAnimationStopped
Event Type
Type Description
EventHandler
API Version
preview

Scrolled

Scrolled will be triggered when the content has been scrolled.

Declaration
public event EventHandler Scrolled
Event Type
Type Description
EventHandler
API Version
preview

Implements

Extension Methods