Class Button

Button is a View that provides an item that invokes an System.Action when activated by the user.
Inheritance
System.Object
Responder
View
Button
Implements
System.Collections.IEnumerable
Inherited Members
System.Object.Equals(System.Object)
System.Object.Equals(System.Object, System.Object)
System.Object.GetHashCode()
System.Object.GetType()
System.Object.MemberwiseClone()
System.Object.ReferenceEquals(System.Object, System.Object)
Namespace: Terminal.Gui
Assembly: Terminal.Gui.dll
Syntax
public class Button : View, IEnumerable
Remarks

Provides a button showing text invokes an System.Action when clicked on with a mouse or when the user presses SPACE, ENTER, or hotkey. The hotkey is specified by the first uppercase letter in the button.

When the button is configured as the default (IsDefault) and the user presses the ENTER key, if no other View processes the KeyEvent, the Button's System.Action will be invoked.

Constructors

Button()

Initializes a new instance of Button using Computed layout.
Declaration
public Button()
Remarks
The width of the Button is computed based on the text length. The height will always be 1.

Button(ustring, Boolean)

Initializes a new instance of Button using Computed layout.
Declaration
public Button(ustring text, bool is_default = false)
Parameters
Type Name Description
NStack.ustring text The button's text
System.Boolean is_default If true, a special decoration is used, and the user pressing the enter key in a Dialog will implicitly activate this button.
Remarks
The width of the Button is computed based on the text length. The height will always be 1.

Button(Int32, Int32, ustring)

Initializes a new instance of Button using Absolute layout, based on the given text
Declaration
public Button(int x, int y, ustring text)
Parameters
Type Name Description
System.Int32 x X position where the button will be shown.
System.Int32 y Y position where the button will be shown.
NStack.ustring text The button's text
Remarks
The width of the Button is computed based on the text length. The height will always be 1.

Button(Int32, Int32, ustring, Boolean)

Initializes a new instance of Button using Absolute layout, based on the given text.
Declaration
public Button(int x, int y, ustring text, bool is_default)
Parameters
Type Name Description
System.Int32 x X position where the button will be shown.
System.Int32 y Y position where the button will be shown.
NStack.ustring text The button's text
System.Boolean is_default If true, a special decoration is used, and the user pressing the enter key in a Dialog will implicitly activate this button.
Remarks
The width of the Button is computed based on the text length. The height will always be 1.

Fields

Clicked

Clicked System.Action, raised when the button is clicked.
Declaration
public Action Clicked
Field Value
Type Description
System.Action
Remarks
Client code can hook up to this event, it is raised when the button is activated either with the mouse or the keyboard.

Properties

IsDefault

Gets or sets whether the Button is the default action to activate in a dialog.
Declaration
public bool IsDefault { get; set; }
Property Value
Type Description
System.Boolean true if is default; otherwise, false.

Text

The text displayed by this Button.
Declaration
public ustring Text { get; set; }
Property Value
Type Description
NStack.ustring

TextAlignment

Sets or gets the text alignment for the Button.
Declaration
public TextAlignment TextAlignment { get; set; }
Property Value
Type Description
TextAlignment

Methods

MouseEvent(MouseEvent)

Method invoked when a mouse event is generated
Declaration
public override bool MouseEvent(MouseEvent me)
Parameters
Type Name Description
MouseEvent me
Returns
Type Description
System.Boolean true, if the event was handled, false otherwise.
Overrides

PositionCursor()

Positions the cursor in the right position based on the currently focused view in the chain.
Declaration
public override void PositionCursor()
Overrides

ProcessColdKey(KeyEvent)

This method can be overwritten by views that want to provide accelerator functionality (Alt-key for example), but without interefering with normal ProcessKey behavior.
Declaration
public override bool ProcessColdKey(KeyEvent kb)
Parameters
Type Name Description
KeyEvent kb
Returns
Type Description
System.Boolean
Overrides
Remarks

After keys are sent to the subviews on the current view, all the view are processed and the key is passed to the views to allow some of them to process the keystroke as a cold-key.

This functionality is used, for example, by default buttons to act on the enter key. Processing this as a hot-key would prevent non-default buttons from consuming the enter keypress when they have the focus.

ProcessHotKey(KeyEvent)

This method can be overwritten by view that want to provide accelerator functionality (Alt-key for example).
Declaration
public override bool ProcessHotKey(KeyEvent kb)
Parameters
Type Name Description
KeyEvent kb
Returns
Type Description
System.Boolean
Overrides
Remarks

Before keys are sent to the subview on the current view, all the views are processed and the key is passed to the widgets to allow some of them to process the keystroke as a hot-key.

For example, if you implement a button that has a hotkey ok "o", you would catch the combination Alt-o here. If the event is caught, you must return true to stop the keystroke from being dispatched to other views.

ProcessKey(KeyEvent)

If the view is focused, gives the view a chance to process the keystroke.
Declaration
public override bool ProcessKey(KeyEvent kb)
Parameters
Type Name Description
KeyEvent kb
Returns
Type Description
System.Boolean
Overrides
Remarks

Views can override this method if they are interested in processing the given keystroke. If they consume the keystroke, they must return true to stop the keystroke from being processed by other widgets or consumed by the widget engine. If they return false, the keystroke will be passed using the ProcessColdKey method to other views to process.

The View implementation does nothing but return false, so it is not necessary to call base.ProcessKey if you derive directly from View, but you should if you derive other View subclasses.

Redraw(Rect)

Redraws this view and its subviews; only redraws the views that have been flagged for a re-display.
Declaration
public override void Redraw(Rect bounds)
Parameters
Type Name Description
Rect bounds The bounds (view-relative region) to redraw.
Overrides
Remarks

Always use Bounds (view-relative) when calling Redraw(Rect), NOT Frame (superview-relative).

Views should set the color that they want to use on entry, as otherwise this will inherit the last color that was set globaly on the driver.

Overrides of Redraw(Rect) must ensure they do not set Driver.Clip to a clip region larger than the region parameter.

Implements

System.Collections.IEnumerable