Wt::WFormWidget Class Reference

An abstract widget that corresponds to an HTML form element. More...

#include <Wt/WFormWidget.h>

Inheritance diagram for Wt::WFormWidget:

Public Member Functions
	WFormWidget ()
	Creates a WFormWidget.
	~WFormWidget ()
	Destructor.
WLabel *	label () const
	Returns the label associated with this widget. More...
virtual void	setHidden (bool hidden, const WAnimation &animation=WAnimation()) override
	Sets the hidden state of this widget. More...
virtual WString	valueText () const =0
	Returns the current value. More...
virtual void	setValueText (const WString &value)=0
	Sets the value text. More...
void	setValidator (const std::shared_ptr< WValidator > &validator)
	Sets a validator for this field. More...
virtual std::shared_ptr< WValidator >	validator () const
	Returns the validator.
virtual ValidationState	validate ()
	Validates the field. More...
void	setEnabled (bool enabled)
	Sets whether the widget is enabled. More...
virtual void	setReadOnly (bool readOnly)
	Sets the element read-only. More...
bool	isReadOnly () const
	Returns whether the form element is read-only. More...
virtual void	setPlaceholderText (const WString &placeholder)
	Sets the placeholder text. More...
const WString &	placeholderText () const
	Returns the placeholder text. More...
EventSignal &	changed ()
	Signal emitted when the value was changed. More...
Signal< WValidator::Result > &	validated ()
	Signal emitted when the widget is being validated. More...
virtual void	refresh () override
	Refresh the widget. More...
virtual void	setToolTip (const WString &text, TextFormat textFormat=TextFormat::Plain) override
	Sets a tooltip. More...
virtual bool	canReceiveFocus () const override
	Returns whether the widget can receive focus. More...
virtual int	tabIndex () const override
	Returns the tab index. More...
Public Member Functions inherited from Wt::WInteractWidget
	WInteractWidget ()
	Create an InteractWidget.
EventSignal< WKeyEvent > &	keyWentDown ()
	Event signal emitted when a keyboard key is pushed down. More...
EventSignal< WKeyEvent > &	keyPressed ()
	Event signal emitted when a "character" was entered. More...
EventSignal< WKeyEvent > &	keyWentUp ()
	Event signal emitted when a keyboard key is released. More...
EventSignal &	enterPressed ()
	Event signal emitted when enter was pressed. More...
EventSignal &	escapePressed ()
	Event signal emitted when escape was pressed. More...
EventSignal< WMouseEvent > &	clicked ()
	Event signal emitted when the primary mouse button was clicked on this widget. More...
EventSignal< WMouseEvent > &	doubleClicked ()
	Event signal emitted when the primary mouse button was double clicked on this widget. More...
EventSignal< WMouseEvent > &	mouseWentDown ()
	Event signal emitted when a mouse button was pushed down on this widget. More...
EventSignal< WMouseEvent > &	mouseWentUp ()
	Event signal emitted when a mouse button was released on this widget. More...
EventSignal< WMouseEvent > &	mouseWentOut ()
	Event signal emitted when the mouse went out of this widget. More...
EventSignal< WMouseEvent > &	mouseWentOver ()
	Event signal emitted when the mouse entered this widget. More...
EventSignal< WMouseEvent > &	mouseMoved ()
	Event signal emitted when the mouse moved over this widget. More...
EventSignal< WMouseEvent > &	mouseDragged ()
	Event signal emitted when the mouse is dragged over this widget. More...
EventSignal< WMouseEvent > &	mouseWheel ()
	Event signal emitted when the mouse scroll wheel was used. More...
EventSignal< WTouchEvent > &	touchStarted ()
	Event signal emitted when a finger is placed on the screen. More...
EventSignal< WTouchEvent > &	touchEnded ()
	Event signal emitted when a finger is removed from the screen. More...
EventSignal< WTouchEvent > &	touchMoved ()
	Event signal emitted when a finger, which is already placed on the screen, is moved across the screen. More...
EventSignal< WGestureEvent > &	gestureStarted ()
	Event signal emitted when a gesture is started. More...
EventSignal< WGestureEvent > &	gestureChanged ()
	Event signal emitted when a gesture is changed. More...
EventSignal< WGestureEvent > &	gestureEnded ()
	Event signal emitted when a gesture is ended. More...
void	setDraggable (const std::string &mimeType, WWidget *dragWidget=nullptr, bool isDragWidgetOnly=false, WObject *sourceWidget=nullptr)
	Configure dragging for drag and drop. More...
void	unsetDraggable ()
	Disable drag & drop for this widget. More...
void	setMouseOverDelay (int delay)
	Sets a delay for the mouse over event. More...
int	mouseOverDelay () const
	Returns the mouse over signal delay. More...
virtual void	setPopup (bool popup) override
	Lets the widget overlay over other sibling widgets. More...
virtual void	load () override
	Loads content just before the widget is used. More...
virtual bool	isEnabled () const override
	Returns whether the widget is enabled. More...
Public Member Functions inherited from Wt::WWebWidget
	WWebWidget ()
	Construct a WebWidget.
virtual std::vector< WWidget * >	children () const override
	Returns child widgets. More...
Signal &	childrenChanged ()
	Signal emitted when children have been added or removed. More...
virtual void	setPositionScheme (PositionScheme scheme) override
	Sets the CSS position scheme. More...
virtual PositionScheme	positionScheme () const override
	Returns the CSS position scheme. More...
virtual void	setOffsets (const WLength &offset, WFlags< Side > sides=AllSides) override
	Sets CSS offsets for a non-statically positioned widget. More...
virtual WLength	offset (Side s) const override
	Returns a CSS offset. More...
virtual void	resize (const WLength &width, const WLength &height) override
	Resizes the widget. More...
virtual WLength	width () const override
	Returns the width. More...
virtual WLength	height () const override
	Returns the height. More...
virtual void	setMinimumSize (const WLength &width, const WLength &height) override
	Sets a minimum size. More...
virtual WLength	minimumWidth () const override
	Returns the minimum width. More...
virtual WLength	minimumHeight () const override
	Returns the minimum height. More...
virtual void	setMaximumSize (const WLength &width, const WLength &height) override
	Sets a maximum size. More...
virtual WLength	maximumWidth () const override
	Returns the maximum width. More...
virtual WLength	maximumHeight () const override
	Returns the maximum height. More...
virtual void	setLineHeight (const WLength &height) override
	Sets the CSS line height for contained text.
virtual WLength	lineHeight () const override
	Returns the CSS line height for contained text. More...
virtual void	setFloatSide (Side s) override
	Specifies a CSS float side. More...
virtual Side	floatSide () const override
	Returns the CSS float side. More...
virtual void	setClearSides (WFlags< Side > sides) override
	Sets the sides that should be cleared of floats. More...
virtual WFlags< Side >	clearSides () const override
	Returns the sides that should remain empty. More...
virtual void	setMargin (const WLength &margin, WFlags< Side > sides=AllSides) override
	Sets CSS margins around the widget. More...
virtual WLength	margin (Side side) const override
	Returns a CSS margin set. More...
virtual void	setHiddenKeepsGeometry (bool enabled) override
	Sets whether the widget keeps its geometry when hidden. More...
virtual bool	hiddenKeepsGeometry () const override
	Returns whether the widget keeps its geometry when hidden. More...
virtual bool	isHidden () const override
	Returns whether the widget is set hidden. More...
virtual bool	isVisible () const override
	Returns whether the widget is visible. More...
virtual void	setDisabled (bool disabled) override
	Sets whether the widget is disabled. More...
virtual bool	isDisabled () const override
	Returns whether the widget is set disabled. More...
virtual bool	isPopup () const override
	Returns whether the widget is overlayed. More...
virtual void	setInline (bool isInline) override
	Sets whether the widget is displayed inline or as a block. More...
virtual bool	isInline () const override
	Returns whether the widget is displayed inline or as block. More...
virtual void	setDecorationStyle (const WCssDecorationStyle &style) override
	Sets a CSS decoration style. More...
virtual WCssDecorationStyle &	decorationStyle () override
	Returns the decoration style of this widget. More...
virtual void	setStyleClass (const WString &styleClass) override
	Sets (one or more) CSS style classes. More...
virtual WString	styleClass () const override
	Returns the CSS style class. More...
virtual void	addStyleClass (const WString &styleClass, bool force=false) override
	Adds a CSS style class. More...
virtual void	removeStyleClass (const WString &styleClass, bool force=false) override
	Removes a CSS style class. More...
virtual bool	hasStyleClass (const WString &styleClass) const override
	Returns whether the widget has a style class.
virtual void	setVerticalAlignment (AlignmentFlag alignment, const WLength &length=WLength()) override
	Sets the vertical alignment. More...
virtual AlignmentFlag	verticalAlignment () const override
	Returns the vertical alignment. More...
virtual WLength	verticalAlignmentLength () const override
	Returns the fixed vertical alignment that was set. More...
virtual void	setDeferredToolTip (bool enable, TextFormat textFormat=TextFormat::Plain) override
	Enable deferred tooltip. More...
virtual WString	toolTip () const override
	Returns the tooltip.
virtual void	setAttributeValue (const std::string &name, const WString &value) override
	Sets an attribute value. More...
virtual WString	attributeValue (const std::string &name) const override
	Returns an attribute value. More...
virtual void	setJavaScriptMember (const std::string &name, const std::string &value) override
	Sets a JavaScript member. More...
virtual std::string	javaScriptMember (const std::string &name) const override
	Returns the value of a JavaScript member. More...
virtual void	callJavaScriptMember (const std::string &name, const std::string &args) override
	Calls a JavaScript member. More...
virtual bool	loaded () const override
	Returns whether this widget has been loaded. More...
virtual void	setId (const std::string &id) override
	Sets the CSS Id. More...
virtual WWidget *	find (const std::string &name) override
	Finds a descendent widget by name. More...
virtual WWidget *	findById (const std::string &id) override
	Finds a descendent widget by id.
virtual void	setSelectable (bool selectable) override
	Sets as selectable. More...
virtual void	doJavaScript (const std::string &javascript) override
	Executes the given JavaScript statements when the widget is rendered or updated. More...
virtual const std::string	id () const override
	Returns the (unique) identifier for this object. More...
void	setLoadLaterWhenInvisible (bool)
	Change the way the widget is loaded when invisible. More...
std::string	htmlTagName () const
	returns the current html tag name More...
void	setHtmlTagName (const std::string &tag)
	set the custom HTML tag name More...
virtual void	setCanReceiveFocus (bool enabled) override
	Sets whether the widget can receive focus. More...
virtual bool	setFirstFocus () override
	Set focus on the widget's first descendant. More...
virtual void	setFocus (bool focus) override
	Sets focus. More...
virtual bool	hasFocus () const override
	Returns whether the widget currently has the focus.
virtual void	setTabIndex (int index) override
	Sets the tab index. More...
EventSignal &	blurred ()
	Signal emitted when the widget lost focus. More...
EventSignal &	focussed ()
	Signal emitted when the widget recieved focus. More...
virtual bool	scrollVisibilityEnabled () const final override
	Returns whether scroll visibility detection is enabled for this widget. More...
virtual void	setScrollVisibilityEnabled (bool enabled) final override
	Sets whether scroll visibility detection is enabled for this widget. More...
virtual int	scrollVisibilityMargin () const final override
	Returns the margin around the viewport within which the widget is considered visible. More...
virtual void	setScrollVisibilityMargin (int margin) final override
	Sets the margin around the viewport within which the widget is considered visible. More...
virtual Signal< bool > &	scrollVisibilityChanged () final override
	Signal triggered when the scroll visibility of this widget changes. More...
virtual bool	isScrollVisible () const final override
	Returns whether this widget is currently considered scroll visible. More...
virtual void	setThemeStyleEnabled (bool enabled) final override
	Sets whether theme styling for a widget is enabled or disabled. More...
virtual bool	isThemeStyleEnabled () const final override
	Returns whether this widget is currently styled by the chosen theme. More...
virtual void	setObjectName (const std::string &name) override
	Sets an object name. More...
void	setFocus ()
	Sets focus. More...
virtual void	setFocus (bool focus)=0
	Sets focus. More...
Public Member Functions inherited from Wt::WWidget
virtual	~WWidget ()
	Destructor. More...
WWidget *	parent () const
	Returns the parent widget.
virtual std::unique_ptr< WWidget >	removeWidget (WWidget *widget)
	Removes a child widget.
template<typename Widget >
std::unique_ptr< Widget >	removeWidget (Widget *widget)
	Removes a child widget. More...
std::unique_ptr< WWidget >	removeFromParent ()
	Removes the widget from its parent. More...
void	setWidth (const WLength &width)
	Sets the width. More...
void	setHeight (const WLength &height)
	Sets the height. More...
virtual void	positionAt (const WWidget *widget, Orientation orientation=Orientation::Vertical)
	Positions a widget next to another widget. More...
virtual void	toggleStyleClass (const WString &styleClass, bool add, bool force=false)
	Toggles a CSS style class.
std::string	jsRef () const
	Returns a JavaScript expression to the corresponding DOM node. More...
void	setFocus ()
	Sets focus. More...
virtual void	acceptDrops (const std::string &mimeType, const WString &hoverStyleClass=WString())
	Sets a mime type to be accepted for dropping. More...
virtual void	stopAcceptDrops (const std::string &mimeType)
	Indicates that a mime type is no longer accepted for dropping. More...
virtual void	htmlText (std::ostream &out)
	Streams the (X)HTML representation. More...
bool	isRendered () const
	Returns whether the widget is rendered. More...
void	hide ()
	Hides the widget. More...
void	animateHide (const WAnimation &animation)
	Hides the widget using an animation. More...
void	show ()
	Shows the widget. More...
void	animateShow (const WAnimation &animation)
	Shows the widget using an animation. More...
void	enable ()
	Enables the widget. More...
void	disable ()
	Disable thes widget. More...
bool	layoutSizeAware () const
	Returns whether the widget is layout size aware. More...
Public Member Functions inherited from Wt::WObject
void	addChild (std::unique_ptr< WObject > child)
	Add a child WObject whose lifetime is determined by this WObject.
template<typename Child >
Child *	addChild (std::unique_ptr< Child > child)
	Add a child WObject, returning a raw pointer. More...
std::unique_ptr< WObject >	removeChild (WObject *child)
	Remove a child WObject, so its lifetime is no longer determined by this WObject.
template<typename Child >
std::unique_ptr< Child >	removeChild (Child *child)
	Remove a child WObject, so its lifetime is no longer determined by this WObject. More...
virtual std::string	objectName () const
	Returns the object name. More...
void	resetLearnedSlots ()
	Resets learned stateless slot implementations. More...
template<class T >
void	resetLearnedSlot (void(T::*method)())
	Resets a learned stateless slot implementation. More...
template<class T >
WStatelessSlot *	implementStateless (void(T::*method)())
	Declares a slot to be stateless and learn client-side behaviour on first invocation. More...
template<class T >
WStatelessSlot *	implementStateless (void(T::*method)(), void(T::*undoMethod)())
	Declares a slot to be stateless and learn client-side behaviour in advance. More...
void	isNotStateless ()
	Marks the current function as not stateless. More...
template<class T >
WStatelessSlot *	implementJavaScript (void(T::*method)(), const std::string &jsCode)
	Provides a JavaScript implementation for a method. More...
Public Member Functions inherited from Wt::Core::observable
	observable () noexcept
	Default constructor.
virtual	~observable ()
	Destructor. More...
template<typename... Args, typename C >
auto	bindSafe (void(C::*method)(Args...)) noexcept
	Protects a method call against object destruction. More...
template<typename... Args, typename C >
auto	bindSafe (void(C::*method)(Args...) const) const noexcept
	Protects a const method call against object destruction. More...
template<typename Function >
auto	bindSafe (const Function &function) noexcept
	Protects a function against object destruction. More...

Protected Member Functions
virtual void	enableAjax () override
	Progresses to an Ajax-enabled widget. More...
virtual void	render (WFlags< RenderFlag > flags) override
	Renders the widget. More...
virtual void	propagateSetEnabled (bool enabled) override
	Propagates that a widget was enabled or disabled through children. More...
Protected Member Functions inherited from Wt::WWebWidget
virtual WStatelessSlot *	getStateless (Method method) override
	On-demand stateless slot implementation. More...
Protected Member Functions inherited from Wt::WWidget
void	setLayoutSizeAware (bool sizeAware)
	Sets the widget to be aware of its size set by a layout manager. More...
virtual void	layoutSizeChanged (int width, int height)
	Virtual method that indicates a size change. More...
	WWidget ()
	Creates a widget.
virtual void	dropEvent (WDropEvent dropEvent)
	Handles a drop event. More...
virtual int	boxPadding (Orientation orientation) const
	Returns the widget's built-in padding. More...
virtual int	boxBorder (Orientation orientation) const
	Returns the widget's built-in border width. More...
void	scheduleRender (WFlags< RepaintFlag > flags=None)
	Schedules rerendering of the widget. More...

Additional Inherited Members
Public Types inherited from Wt::WObject
typedef void(WObject::*	Method) ()
	Typedef for a WObject method without arguments.
Static Public Member Functions inherited from Wt::WWebWidget
static std::string	jsStringLiteral (const std::string &v, char delimiter='\'')
	Turn a CharEncoding::UTF8 encoded string into a JavaScript string literal. More...
Static Public Member Functions inherited from Wt::WWidget
static WString	tr (const char *key)
	Short hand for WString::tr() More...

Detailed Description

An abstract widget that corresponds to an HTML form element.

A WFormWidget may receive focus (see canReceiveFocus()), can be disabled, and can have a label that acts as proxy for getting focus. It provides signals which reflect changes to its value, or changes to its focus.

Form widgets also have built-in support for validation, using setValidator(const std::shared_ptr<WValidator> &). If the validator provide client-side validation, then an invalid validation state is reflected using the style class "Wt-invalid". All validators provided by Wt implement client-side validation.

On the server-side, use validate() method to validate the content using a validator previously set.

Member Function Documentation

canReceiveFocus()

bool Wt::WFormWidget::canReceiveFocus ( ) const

overridevirtual

Returns whether the widget can receive focus.

See also

setCanReceiveFocus()

Reimplemented from Wt::WWebWidget.

changed()

EventSignal & Wt::WFormWidget::changed

(

)

Signal emitted when the value was changed.

For a keyboard input, the signal is only emitted when the focus is lost

enableAjax()

void Wt::WFormWidget::enableAjax ( )

overrideprotectedvirtual

Progresses to an Ajax-enabled widget.

This method is called when the progressive bootstrap method is used, and support for AJAX has been detected. The default behavior will upgrade the widget's event handling to use AJAX instead of full page reloads, and propagate the call to its children.

You may want to reimplement this method if you want to make changes to widget when AJAX is enabled. You should always call the base implementation.

See also

WApplication::enableAjax()

Reimplemented from Wt::WWebWidget.

Reimplemented in Wt::WSlider, and Wt::WPushButton.

isReadOnly()

bool Wt::WFormWidget::isReadOnly

(

)

const

Returns whether the form element is read-only.

See also

setReadOnly()

label()

WLabel* Wt::WFormWidget::label

(

)

const

Returns the label associated with this widget.

Returns the label (if there is one) that acts as a proxy for this widget.

See also

WLabel::setBuddy(WFormWidget *)

placeholderText()

const WString& Wt::WFormWidget::placeholderText

(

)

const

Returns the placeholder text.

See also

setPlaceholderText()

propagateSetEnabled()

void Wt::WFormWidget::propagateSetEnabled ( bool  enabled )

overrideprotectedvirtual

Propagates that a widget was enabled or disabled through children.

When enabling or disabling a widget, you usually also want to disable contained children. This method is called by setDisabled() to propagate its state to all children.

You may want to reimplement this method if they wish to render differently when a widget is disabled. The default implementation will propagate the signal to all children.

Reimplemented from Wt::WInteractWidget.

Reimplemented in Wt::WTimeEdit, Wt::WTextEdit, Wt::WPushButton, and Wt::WDateEdit.

refresh()

void Wt::WFormWidget::refresh ( )

overridevirtual

Refresh the widget.

The refresh method is invoked when the locale is changed using WApplication::setLocale() or when the user hit the refresh button.

The widget must actualize its contents in response.

Note

This does not rerender the widget! Calling refresh() usually does not have any effect (unless you've reimplemented refresh() to attach to it an effect).

Reimplemented from Wt::WWebWidget.

Reimplemented in Wt::WPushButton, Wt::WDoubleSpinBox, Wt::WDateEdit, Wt::WComboBox, Wt::WAbstractToggleButton, and Wt::WAbstractSpinBox.

render()

void Wt::WFormWidget::render ( WFlags< RenderFlag >  flags )

overrideprotectedvirtual

Renders the widget.

This function renders the widget (or an update for the widget), after this has been scheduled using scheduleRender().

The default implementation will render the widget by serializing changes to JavaScript and HTML. You may want to reimplement this widget if you have been postponing some of the layout / rendering implementation until the latest moment possible. In that case you should make sure you call the base implementation however.

Reimplemented from Wt::WWebWidget.

Reimplemented in Wt::WTimeEdit, Wt::WSlider, Wt::WLineEdit, Wt::WEmailEdit, Wt::WDoubleSpinBox, Wt::WDateEdit, and Wt::WAbstractSpinBox.

setEnabled()

void Wt::WFormWidget::setEnabled

(

bool

enabled

)

Sets whether the widget is enabled.

A widget that is disabled cannot receive focus or user interaction.

This is the opposite of setDisabled().

setHidden()

void Wt::WFormWidget::setHidden ( bool  hidden, const WAnimation &  animation = WAnimation()  )

overridevirtual

Sets the hidden state of this widget.

If the widget has a label, it is hidden and shown together with this widget.

Reimplemented from Wt::WWebWidget.

Reimplemented in Wt::WTimeEdit, and Wt::WDateEdit.

setPlaceholderText()

void Wt::WFormWidget::setPlaceholderText ( const WString &  placeholder )

virtual

Sets the placeholder text.

This sets the text that is shown when the field is empty.

Reimplemented in Wt::WTextEdit.

setReadOnly()

void Wt::WFormWidget::setReadOnly ( bool  readOnly )

virtual

Sets the element read-only.

A read-only form element cannot be edited, but the contents can still be selected.

By default, a form element area is not read-only.

See also

setEnabled()

Reimplemented in Wt::WTextEdit.

setToolTip()

void Wt::WFormWidget::setToolTip ( const WString &  text, TextFormat  textFormat = TextFormat::Plain  )

overridevirtual

Sets a tooltip.

The tooltip is displayed when the cursor hovers over the widget.

When textFormat is TextFormat::XHTML, the tooltip may contain any valid XHTML snippet. The tooltip will then be rendered using JavaScript.

Note: This will set deferred tooltip to false.

See also

setDeferredTooltip()

Reimplemented from Wt::WWebWidget.

setValidator()

void Wt::WFormWidget::setValidator

(

const std::shared_ptr< WValidator > &

validator

)

Sets a validator for this field.

The validator is used to validate the current input.

The default value is 0.

See also

validate()

setValueText()

virtual void Wt::WFormWidget::setValueText ( const WString &  value )

pure virtual

Sets the value text.

This sets the current value from a string value.

Implemented in Wt::WSlider, Wt::WPushButton, Wt::WLineEdit, Wt::WEmailEdit, Wt::WComboBox, Wt::WColorPicker, Wt::WTextArea, and Wt::WAbstractToggleButton.

tabIndex()

int Wt::WFormWidget::tabIndex ( ) const

overridevirtual

Returns the tab index.

See also

setTabIndex()

Reimplemented from Wt::WWebWidget.

validate()

ValidationState Wt::WFormWidget::validate ( )

virtual

Validates the field.

See also

validated()

Reimplemented in Wt::WLineEdit, and Wt::WAbstractSpinBox.

validated()

Signal<WValidator::Result>& Wt::WFormWidget::validated

(

)

Signal emitted when the widget is being validated.

This signal may be useful to react to a changed validation state.

See also

validate()

valueText()

virtual WString Wt::WFormWidget::valueText ( ) const

pure virtual

Returns the current value.

This returns the current value as a string.

Implemented in Wt::WTextArea, Wt::WSlider, Wt::WPushButton, Wt::WLineEdit, Wt::WEmailEdit, Wt::WComboBox, Wt::WColorPicker, and Wt::WAbstractToggleButton.