Namespace Terminal.Gui.ViewBase

Core view system, base classes, layout primitives, and adornments.

The ViewBase namespace contains the foundational view architecture for all Terminal.Gui UI elements.

Key Types

View - Base class for all UI elements
Adornment / Margin / Border / Padding - Visual decorations around content
Pos / Dim - Flexible positioning and sizing system
ViewArrangement - User interaction flags (Movable, Resizable, Overlapped)
IValue<T> - Interface for views with strongly-typed values

View Architecture

Views are composed of nested layers:

Frame - Outer rectangle in SuperView coordinates
Margin - Transparent spacing outside Border
Border - Visual frame with title and line style
Padding - Spacing inside Border
Viewport - Visible window into content area
Content Area - Where content is drawn (can be larger than Viewport for scrolling)

Example

View view = new ()
{
    X = Pos.Center (),
    Y = Pos.Center (),
    Width = Dim.Percent (50),
    Height = Dim.Auto (),
    Title = "My View",
    BorderStyle = LineStyle.Rounded,
    Arrangement = ViewArrangement.Movable | ViewArrangement.Resizable
};

Pos: Describes the position of a View which can be an absolute value, a percentage, centered, or relative to the ending dimension. Integer values are implicitly convertible to an absolute Pos. These objects are created using the static methods Percent, AnchorEnd, and Center. The Pos objects can be combined with the addition and subtraction operators.

PosAbsolute: Represents an absolute position in the layout. This is used to specify a fixed position in the layout.

PosAlign: Enables alignment of a set of views.

PosAnchorEnd: Represents a position anchored to the end (right side or bottom) of the SuperView's content area.

PosCenter: Represents a position that is centered.

PosCombine: Represents a position that is a combination of two other positions.

PosFunc: Represents a position that is computed by executing a function that returns an integer position.

PosPercent: Represents a position that is a percentage of the width or height of the SuperView.

PosView: Represents a position that is anchored to the side of another view.

SideExtensions: Extension methods for the Side enum type.

SizeChangedEventArgs: Args for events about Size (e.g. Resized)

StackExtensions: Extension of Stack<T> helper to work with specific IEqualityComparer<T>

SuperViewChangedEventArgs: Args for events where the SuperView of a View is changed (e.g. Removed).

View

View is the base class all visible elements. View can render itself and contains zero or more nested views, called SubViews. View provides basic functionality for layout, arrangement, and drawing. In addition, View provides keyboard and mouse event handling.

See the View Deep Dive for more.

ViewDiagnosticFlagsExtensions: Extension methods for the ViewDiagnosticFlags enum type.

ViewEventArgs: Args for events that relate to specific View

ViewManipulator: Helper class that encapsulates view manipulation operations for arrangement (move/resize). Provides methods to move and resize a view while respecting minimum size constraints.

Interfaces

IDesignable: Interface declaring common functionality useful for designer implementations.

IMouseHoldRepeater

Handler for raising periodic events while the mouse is held down. Typically, mouse button only needs to be pressed down in a view to begin this event after which it can be moved elsewhere.

Common use cases for this includes holding a button down to increase a counter (e.g. in NumericUpDown).

IOrientation: Implement this interface to provide orientation support.

IValue: Non-generic interface for accessing a View's value as a boxed object.

IValue<TValue>: Interface for views that provide a strongly-typed value.

Enums

AddOrSubtract: Describes whether an operation should add or subtract values.

Alignment: Determines the position of items when arranged in a container.

AlignmentModes: Determines alignment modes for Alignment.

ArrangeButtons: Identifies the different arrangement buttons that can be displayed on a border during arrange mode.

BorderSettings: Determines the settings for Border.

DimAutoStyle: Specifies how Auto(DimAutoStyle, Dim?, Dim?) will compute the dimension. See the Dim.Auto Deep Dive for comprehensive documentation.

DimPercentMode: Indicates the mode for a DimPercent object.

Dimension: Indicates the dimension for Dim operations.

MouseState: Used to describe the state of the mouse in relation to a View (MouseState) and to specify visual effects, such as highlighting a button when the mouse is over it or changing the appearance of a view when the mouse is pressed (MouseHighlightStates).

NavigationDirection: Indicates navigation direction.

Orientation: Direction of an element (horizontal or vertical)

ShadowStyle: Defines the style of shadow to be drawn on the right and bottom sides of the View.

Side: Indicates the side for Pos operations.

TabBehavior: Describes how TabStop behaves. A TabStop is a stop-point for keyboard navigation between Views.

ViewArrangement: Describes what user actions are enabled for arranging a View within it's SuperView . See Arrangement.

ViewDiagnosticFlags: Enables diagnostic functions for View.

ViewportSettingsFlags: Settings for how the Viewport behaves.

Delegates

View.CommandImplementation: Function signature commands.

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