Class ScrollbarControl

Namespace

SharpConsoleUI.Controls

Assembly

SharpConsoleUI.dll

A standalone scrollbar control, decoupled from any single scrollable view. One ScrollbarControl can drive several views at once — the case that motivated it (issue #85) is a side-by-side diff viewer where one bar must scroll two panes together.

public class ScrollbarControl : BaseControl, IDOMPaintable, INotifyPropertyChanged, IMouseAwareControl, IWindowControl, IDisposable

Inheritance

object

BaseControl

ScrollbarControl

Implements

IDOMPaintable

INotifyPropertyChanged

IMouseAwareControl

IWindowControl

IDisposable

Inherited Members

BaseControl.PropertyChanged

BaseControl.GotFocus

BaseControl.LostFocus

BaseControl.Bindings

BaseControl.OnPropertyChanged(string)

BaseControl.SubscribeToFocusManager()

BaseControl.SetProperty<T>(ref T, T, string)

BaseControl.SetProperty<T>(ref T, T, Func<T, T>, string)

BaseControl.ActualX

BaseControl.ActualY

BaseControl.ActualWidth

BaseControl.ActualHeight

BaseControl.HorizontalAlignment

BaseControl.VerticalAlignment

BaseControl.Margin

BaseControl.StickyPosition

BaseControl.Name

BaseControl.Tag

BaseControl.Visible

BaseControl.Width

BaseControl.Height

BaseControl.Invalidate(Invalidation)

BaseControl.Invalidate()

BaseControl.Invalidate(bool)

BaseControl.SetActualBounds(LayoutRect)

BaseControl.Dispose()

BaseControl.ComputeHasFocus()

BaseControl.ComputeIsInFocusPath()

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Extension Methods

WindowControlExtensions.GetParentWindow(IWindowControl)

WindowControlExtensions.GetPortalAncestor(IWindowControl)

BindingExtensions.BindTwoWay<TControl, TSource, TValue>(TControl, TSource, Expression<Func<TSource, TValue>>, Expression<Func<TControl, TValue>>)

BindingExtensions.BindTwoWay<TControl, TSource, TSrc, TTgt>(TControl, TSource, Expression<Func<TSource, TSrc>>, Expression<Func<TControl, TTgt>>, Func<TSrc, TTgt>, Func<TTgt, TSrc>)

BindingExtensions.BindTwoWay<TBuilder, TControl, TSource, TValue>(TBuilder, TSource, Expression<Func<TSource, TValue>>, Expression<Func<TControl, TValue>>)

BindingExtensions.BindTwoWay<TBuilder, TControl, TSource, TSrc, TTgt>(TBuilder, TSource, Expression<Func<TSource, TSrc>>, Expression<Func<TControl, TTgt>>, Func<TSrc, TTgt>, Func<TTgt, TSrc>)

BindingExtensions.Bind<TControl, TSource, TValue>(TControl, TSource, Expression<Func<TSource, TValue>>, Expression<Func<TControl, TValue>>)

BindingExtensions.Bind<TControl, TSource, TSrc, TTgt>(TControl, TSource, Expression<Func<TSource, TSrc>>, Expression<Func<TControl, TTgt>>, Func<TSrc, TTgt>)

BindingExtensions.Bind<TBuilder, TControl, TSource, TValue>(TBuilder, TSource, Expression<Func<TSource, TValue>>, Expression<Func<TControl, TValue>>)

BindingExtensions.Bind<TBuilder, TControl, TSource, TSrc, TTgt>(TBuilder, TSource, Expression<Func<TSource, TSrc>>, Expression<Func<TControl, TTgt>>, Func<TSrc, TTgt>)

Remarks

Built on the shared engine in SharpConsoleUI.Helpers.Scrollbar (ScrollbarMetrics, SharpConsoleUI.Helpers.Scrollbar.ScrollbarGeometry, SharpConsoleUI.Helpers.Scrollbar.ScrollbarInput, SharpConsoleUI.Helpers.Scrollbar.ScrollbarRenderer, ScrollbarPaletteResolver) that every built-in scrolling control now shares, so this bar behaves identically to the one embedded in, say, ScrollablePanelControl.

The two events are the point of the control: ValueChanged fires on every change, including a code-set Value (conventional, INPC-consistent); UserValueChanged fires only for a change the user made through the bar (arrow, track page, thumb drag, wheel). A composite wires UserValueChanged to push the new offset to its views, and the views' own scroll events back to Value — with no echo and no guard flag needed, because a code-set Value never re-raises UserValueChanged.

Constructors

ScrollbarControl()

Initializes a new instance of the ScrollbarControl class.

public ScrollbarControl()

Properties

CanFocusWithMouse

A scrollbar cannot be focused by a mouse click either — only dragged/clicked for its own scrolling behaviour.

public bool CanFocusWithMouse { get; }

Property Value

bool

CanReceiveFocus

A scrollbar is a bar, not a tab stop: it never takes keyboard focus.

public bool CanReceiveFocus { get; }

Property Value

bool

Container

Gets or sets the parent container that hosts this control.

public override IContainer? Container { get; set; }

Property Value

IContainer

ContentWidth

Gets the minimum width needed to display the control's content, including margins. Returns null if width cannot be determined. This is calculated based on content (text length, child controls, etc.) and represents the natural/intrinsic size.

public override int? ContentWidth { get; }

Property Value

int?

IsActive

Gets or sets whether the bar paints itself as focused, even though it is never itself a Tab stop. A composite that drives several sibling views sets this to true while one of those views actually holds focus, so the bar's colour still reflects "the group is active."

public bool IsActive { get; set; }

Property Value

bool

IsEnabled

Gets or sets whether the bar is enabled. A disabled bar dims to its unfocused colours and ignores mouse input.

public bool IsEnabled { get; set; }

Property Value

bool

LargeChange

Gets or sets the amount Value moves for a track (page) click. Defaults to ViewportLength when never set explicitly.

public int LargeChange { get; set; }

Property Value

int

Maximum

Gets or sets the total length of the content being scrolled. Shrinking this re-clamps Value to the new range.

public int Maximum { get; set; }

Property Value

int

Orientation

Gets or sets the bar's orientation. Defaults to Vertical.

public ScrollbarOrientation Orientation { get; set; }

Property Value

ScrollbarOrientation

ScrollbarColor

Gets or sets the track colour. When null (the default), the track uses the shared scrollbar engine's focus-aware theme colour.

public Color? ScrollbarColor { get; set; }

Property Value

Color?

ScrollbarThumbColor

Gets or sets the thumb colour. When null (the default), the thumb uses the shared scrollbar engine's focus-aware theme colour.

public Color? ScrollbarThumbColor { get; set; }

Property Value

Color?

SmallChange

Gets or sets the amount Value moves for an arrow click or a mouse wheel notch. Defaults to DefaultScrollWheelLines.

public int SmallChange { get; set; }

Property Value

int

Value

Gets or sets the current scroll offset, clamped to [0, Maximum - ViewportLength]. Every change — including this one, set by code — raises ValueChanged. Only a change made through the bar (arrow, track, drag, wheel) additionally raises UserValueChanged.

public int Value { get; set; }

Property Value

int

ViewportLength

Gets or sets the visible length of the view the bar represents. Shrinking or growing this re-clamps Value to the new range, and — when LargeChange was never set explicitly — changes the default paging amount to match.

public int ViewportLength { get; set; }

Property Value

int

WantsMouseEvents

Whether this control wants to receive mouse events

public bool WantsMouseEvents { get; }

Property Value

bool

Methods

GetLogicalContentSize()

Gets the logical size of the control's content without rendering.

public override Size GetLogicalContentSize()

Returns

Size

The size representing the content's natural dimensions.

MeasureDOM(LayoutConstraints)

Measures the control's desired size given the available constraints.

public override LayoutSize MeasureDOM(LayoutConstraints constraints)

Parameters

constraints LayoutConstraints

The layout constraints (min/max width/height).

Returns

LayoutSize

The desired size of the control.

OnDisposing()

Called during Dispose() before Container is set to null. Override to perform control-specific cleanup (null events, close portals, clear data, etc.).

protected override void OnDisposing()

PaintDOM(CharacterBuffer, LayoutRect, LayoutRect, Color, Color)

Paints the control's content directly to a CharacterBuffer.

public override void PaintDOM(CharacterBuffer buffer, LayoutRect bounds, LayoutRect clipRect, Color defaultForeground, Color defaultBackground)

Parameters

buffer CharacterBuffer

The buffer to paint to.

bounds LayoutRect

The absolute bounds where the control should paint.

clipRect LayoutRect

The clipping rectangle (visible area).

defaultForeground Color

The default foreground color from the container.

defaultBackground Color

The default background color from the container.

ProcessMouseEvent(MouseEventArgs)

Processes a mouse event for this control

public bool ProcessMouseEvent(MouseEventArgs args)

Parameters

args MouseEventArgs

Mouse event arguments with control-relative coordinates

Returns

bool

True if the event was handled and should not propagate further

Events

MouseClick

Event fired when the control is clicked

public event EventHandler<MouseEventArgs>? MouseClick

Event Type

EventHandler<MouseEventArgs>

MouseDoubleClick

Event fired when the control is double-clicked

public event EventHandler<MouseEventArgs>? MouseDoubleClick

Event Type

EventHandler<MouseEventArgs>

MouseEnter

Event fired when the mouse enters the control area

public event EventHandler<MouseEventArgs>? MouseEnter

Event Type

EventHandler<MouseEventArgs>

MouseLeave

Event fired when the mouse leaves the control area

public event EventHandler<MouseEventArgs>? MouseLeave

Event Type

EventHandler<MouseEventArgs>

MouseMove

Event fired when the mouse moves over the control

public event EventHandler<MouseEventArgs>? MouseMove

Event Type

EventHandler<MouseEventArgs>

MouseRightClick

Event fired when the control is right-clicked (Button3)

public event EventHandler<MouseEventArgs>? MouseRightClick

Event Type

EventHandler<MouseEventArgs>

UserValueChanged

Occurs only when the user changes Value through the bar itself: an arrow click, a track page click, a thumb drag, or a mouse wheel notch. Never raised by a code-set Value. A composite subscribes to this (not ValueChanged) to push the new offset to the views it drives, then writes the same value back to Value without causing an echo, since that write raises only ValueChanged.

public event EventHandler<int>? UserValueChanged

Event Type

EventHandler<int>

ValueChanged

Occurs whenever Value changes, however it changed — including a value set by code. Matches the conventional, INPC-consistent behaviour of ValueChanged.

public event EventHandler<int>? ValueChanged

Event Type

EventHandler<int>