Table of Contents

Class ScrollViewer

Namespace
Stride.UI.Controls
Assembly
Stride.UI.dll

Represents a scroll viewer. A scroll viewer element has an infinite virtual size defined by its ScrollingMode. The user can move in that virtual size by touching and panning on the screen.

[DataContract("ScrollViewer")]
[DataContractMetadataType(typeof(ScrollViewer.ScrollViewerMetadata))]
public class ScrollViewer : ContentControl, IUIElementUpdate, IUIElementChildren, IIdentifiable
Inheritance
ScrollViewer
Implements
Inherited Members
Extension Methods

Constructors

ScrollViewer() 

public ScrollViewer()

Fields

CurrentScrollingSpeed

The current speed of the scrolling in virtual pixels.

protected Vector3 CurrentScrollingSpeed

Field Value

Vector3

ScrollOffsets

The current offsets (in virtual pixels) generated by the scrolling on the Content element.

protected Vector3 ScrollOffsets

Field Value

Vector3

Properties

Content

Gets or sets the content of the ContentControl.

public override UIElement Content { get; set; }

Property Value

UIElement

Exceptions

InvalidOperationException

The value passed has already a parent.

ContentAsAnchorInfo

The current content casted as IScrollAnchorInfo

protected IScrollAnchorInfo ContentAsAnchorInfo { get; }

Property Value

IScrollAnchorInfo

Remarks

Null if the Content does not implement the interface

ContentAsScrollInfo

The current content casted as IScrollInfo.

protected IScrollInfo ContentAsScrollInfo { get; }

Property Value

IScrollInfo

Remarks

Null if the Content does not implement the interface

Deceleration

The automatic deceleration of the scroll after the user remove its finger from the screen. The unit is in virtual pixels.

[DataMember]
[Display(null, "Behavior")]
public float Deceleration { get; set; }

Property Value

float

IsEnabled

Gets or sets a value indicating whether this element is enabled in the user interface (UI).

public override bool IsEnabled { set; }

Property Value

bool

IsTouchedDown

Gets a value that indicates whether the is currently touched down.

protected virtual bool IsTouchedDown { get; set; }

Property Value

bool

IsUserScrollingViewer

Indicate if the user is currently touching the scroll viewer and performing a scroll gesture with its finger.

protected bool IsUserScrollingViewer { get; }

Property Value

bool

LastFrameTranslation

Gets the scrolling translation that occurred during the last frame

protected Vector3 LastFrameTranslation { get; }

Property Value

Vector3

ScrollBarColor

Gets or sets the color of the scrolling bar.

[DataMember]
[Display(null, "Appearance")]
public Color ScrollBarColor { get; set; }

Property Value

Color

ScrollBarThickness

Gets or sets the scrolling bar thickness in virtual pixels.

[DataMember]
[Display(null, "Appearance")]
public float ScrollBarThickness { get; set; }

Property Value

float

ScrollMode

The viewer allowed scrolling mode.

[DataMember]
[Display(null, "Behavior")]
public ScrollingMode ScrollMode { get; set; }

Property Value

ScrollingMode

ScrollPosition

The current scroll position (in virtual pixels) of the ScrollViewer. That is, the position of the left-top-front corner of the ScrollViewer in its Content.

public Vector3 ScrollPosition { get; }

Property Value

Vector3

Remarks

If the Content of the scroll viewer implements the IScrollInfo interface, the ScrollPosition will be 0 in all directions where CanScroll(Orientation) is true.

Note that ScrollPosition is valid only when IsArrangeValid is true. If IsArrangeValid is false, ScrollPosition contains the position of the scrolling before the action that actually invalidated the layout.

ScrollStartThreshold

Gets or sets the threshold distance over which a touch move starts scrolling.

[DataMember]
[Display(null, "Behavior")]
public float ScrollStartThreshold { get; set; }

Property Value

float

SnapToAnchors

Gets or sets the value indicating if the element should snap its scrolling to anchors.

[DataMember]
[Display(null, "Behavior")]
public bool SnapToAnchors { get; set; }

Property Value

bool

Remarks

Snapping will work only if Content implements interface IScrollAnchorInfo

TouchScrollingEnabled

Gets or sets the scrolling behavior on touches. True to allow the user to scroll by touching, false to forbid it.

[DataMember]
[Display(null, "Behavior")]
public bool TouchScrollingEnabled { get; set; }

Property Value

bool

ViewPort

The viewport of the ScrollViewer in virtual pixels.

public Vector3 ViewPort { get; }

Property Value

Vector3

Methods

ArrangeOverride(Vector3)

When overridden in a derived class, positions possible child elements and determines a size for a UIElement derived class.

protected override Vector3 ArrangeOverride(Vector3 finalSizeWithoutMargins)

Parameters

finalSizeWithoutMargins Vector3

The final area within the parent that this element should use to arrange itself and its children.

Returns

Vector3

The actual size used.

CanScroll(Orientation)

Indicate if the scroll viewer can scroll in the given direction.

public bool CanScroll(Orientation direction)

Parameters

direction Orientation

The direction to use for the test

Returns

bool

true if the scroll viewer can scroll in the provided direction, or else false

HideScrollBars() 

protected void HideScrollBars()

InvalidateAnchorInfo()

Called by an IScrollAnchorInfo interface that attached to a ScrollViewer when the value of any anchor changed.

public void InvalidateAnchorInfo()

InvalidateScrollInfo()

Called by an IScrollInfo interface that is attached to a ScrollViewer when the value of any scrolling property size changes. Scrolling properties include offset, extent, or viewport.

public void InvalidateScrollInfo()

MeasureOverride(Vector3)

When overridden in a derived class, measures the size in layout required for possible child elements and determines a size for the UIElement-derived class.

protected override Vector3 MeasureOverride(Vector3 availableSizeWithoutMargins)

Parameters

availableSizeWithoutMargins Vector3

The available size that this element can give to child elements. Infinity can be specified as a value to indicate that the element will size to whatever content is available.

Returns

Vector3

The size desired by the children

OnPreviewTouchDown(TouchEventArgs)

The class handler of the event PreviewTouchDown. This method can be overridden in inherited classes to perform actions common to all instances of a class.

protected override void OnPreviewTouchDown(TouchEventArgs args)

Parameters

args TouchEventArgs

The arguments of the event

OnPreviewTouchMove(TouchEventArgs)

The class handler of the event PreviewTouchMove. This method can be overridden in inherited classes to perform actions common to all instances of a class.

protected override void OnPreviewTouchMove(TouchEventArgs args)

Parameters

args TouchEventArgs

The arguments of the event

OnPreviewTouchUp(TouchEventArgs)

The class handler of the event PreviewTouchUp. This method can be overridden in inherited classes to perform actions common to all instances of a class.

protected override void OnPreviewTouchUp(TouchEventArgs args)

Parameters

args TouchEventArgs

The arguments of the event

OnScrollModeChanged()

Method triggered when ScrollMode changed. Can be overridden in inherited class to change the default behavior.

protected virtual void OnScrollModeChanged()

OnTouchEnter(TouchEventArgs)

The class handler of the event TouchEnter. This method can be overridden in inherited classes to perform actions common to all instances of a class.

protected override void OnTouchEnter(TouchEventArgs args)

Parameters

args TouchEventArgs

The arguments of the event

OnTouchLeave(TouchEventArgs)

The class handler of the event TouchLeave. This method can be overridden in inherited classes to perform actions common to all instances of a class.

protected override void OnTouchLeave(TouchEventArgs args)

Parameters

args TouchEventArgs

The arguments of the event

OnTouchScrollingEnabledChanged()

Method triggered when TouchScrollingEnabled changed. Can be overridden in inherited class to change the default behavior.

protected virtual void OnTouchScrollingEnabledChanged()

ScrollOf(Vector3, bool)

Try to scroll of the provided scrolling translation value from the current position. If the provided translation is too important, it is clamped.

public void ScrollOf(Vector3 scrollTranslation, bool stopScrolling = true)

Parameters

scrollTranslation Vector3

The scroll translation to perform (in virtual pixels)

stopScrolling bool

Indicate if the scrolling should be stopped after the scroll action.

ScrollOfInternal(ref Vector3, bool) 

public void ScrollOfInternal(ref Vector3 scrollTranslation, bool stopScrolling)

Parameters

scrollTranslation Vector3
stopScrolling bool

ScrollTo(Vector3, bool)

Try to scroll to the provided position (in virtual pixels). If the provided translation is too important, it is clamped.

public void ScrollTo(Vector3 scrollAbsolutePosition, bool stopScrolling = true)

Parameters

scrollAbsolutePosition Vector3

The scroll offsets to apply

stopScrolling bool

Indicate if the scrolling should be stopped after the scroll action.

Remarks

Note that the computational cost of ScrollTo(Vector3, bool) can be greatly higher than ScrollOf(Vector3, bool) when scrolling is delegated to a Content virtualizing its items. When possible, prefer call to ScrollOf(Vector3, bool)

ScrollToBeginning(Orientation, bool)

Go to the beginning of the scroll viewer's content in the provided direction.

public void ScrollToBeginning(Orientation direction, bool stopScrolling = true)

Parameters

direction Orientation

The direction in which to scroll

stopScrolling bool

Indicate if the scrolling should be stopped after the scroll action.

ScrollToEnd(Orientation, bool)

Go to the end of the scroll viewer's content in the provided direction.

public void ScrollToEnd(Orientation direction, bool stopScrolling = true)

Parameters

direction Orientation

The direction in which to scroll

stopScrolling bool

Indicate if the scrolling should be stopped after the scroll action.

StopCurrentScrolling()

Stops the scrolling at the current position.

public void StopCurrentScrolling()

Update(GameTime)

Method called by Update(GameTime). This method can be overridden by inherited classes to perform time-based actions. This method is not in charge to recursively call the update on child elements, this is automatically done.

protected override void Update(GameTime time)

Parameters

time GameTime

The current time of the game

UpdateWorldMatrix(ref Matrix, bool)

Method called by UpdateWorldMatrix(ref Matrix, bool). Parents are in charge of recursively calling this function on their children.

protected override void UpdateWorldMatrix(ref Matrix parentWorldMatrix, bool parentWorldChanged)

Parameters

parentWorldMatrix Matrix

The world matrix of the parent.

parentWorldChanged bool

Boolean indicating if the world matrix provided by the parent changed

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