A widget that renders an XHTML template. More...

#include <Wt/WTemplate.h>

Inheritance diagram for Wt::WTemplate:

Classes
struct	Functions
	A collection of predefined functions. More...

Public Types
typedef TemplateWidgetIdMode	WidgetIdMode
	Typedef for enum Wt::TemplateWidgetIdMode.

typedef std::function< bool(WTemplate *t, const std::vector< WString > &args, std::ostream &result)>	Function
	A function type. More...

Public Types inherited from Wt::WObject
typedef void(WObject::*	Method) ()
	Typedef for a WObject method without arguments.

Public Member Functions
	WTemplate ()
	Creates a template widget.

	WTemplate (const WString &text)
	Creates a template widget with given template. More...

virtual WString	templateText () const
	Returns the template. More...

void	setTemplateText (const WString &text, TextFormat textFormat=TextFormat::XHTML)
	Sets the template text. More...

void	setWidgetIdMode (TemplateWidgetIdMode mode)
	Sets how the varName should be reflected on bound widgets. More...

TemplateWidgetIdMode	widgetIdMode () const
	Returns how the varName is reflected on a bound widget. More...

virtual void	bindString (const std::string &varName, const WString &value, TextFormat textFormat=TextFormat::XHTML)
	Binds a string value to a variable. More...

void	bindInt (const std::string &varName, int value)
	Binds an integer value to a variable. More...

virtual void	bindWidget (const std::string &varName, std::unique_ptr< WWidget > widget)
	Binds a widget to a variable. More...

template<typename Widget >
Widget *	bindWidget (const std::string &varName, std::unique_ptr< Widget > widget)
	Binds a widget to a variable, returning a raw pointer. More...

template<typename Widget , typename ... Args>
Widget *	bindNew (const std::string &varName, Args &&...args)
	Creates a new widget with the given arguments, and binds it, returning a raw pointer. More...

std::unique_ptr< WWidget >	removeWidget (const std::string &varName)
	Unbinds a widget by variable name. More...

virtual std::unique_ptr< WWidget >	removeWidget (WWidget *widget) override
	Unbinds a widget by widget pointer. More...

void	bindEmpty (const std::string &varName)
	Binds an empty string to a variable. More...

void	addFunction (const std::string &name, const Function &function)
	Binds a function. More...

void	setCondition (const std::string &name, bool value)
	Sets a condition. More...

virtual bool	conditionValue (const std::string &name) const
	Returns a condition value. More...

std::set< std::string >	conditionsSet ()
	Returns the set of conditions set to true.

virtual void	resolveString (const std::string &varName, const std::vector< WString > &args, std::ostream &result)
	Resolves the string value for a variable name. More...

virtual void	handleUnresolvedVariable (const std::string &varName, const std::vector< WString > &args, std::ostream &result)
	Handles a variable that could not be resolved. More...

virtual WWidget *	resolveWidget (const std::string &varName)
	Resolves a widget for a variable name. More...

virtual const WString &	resolveStringValue (const std::string &varName)
	Resolves a string that was bound to a variable name. More...

virtual bool	resolveFunction (const std::string &name, const std::vector< WString > &args, std::ostream &result)
	Resolves a function call. More...

template<typename T >
T	resolve (const std::string &varName)
	Returns a widget for a variable name. More...

virtual void	clear ()
	Erases all variable bindings. More...

void	setInternalPathEncoding (bool enabled)
	Enables internal path anchors in the XHTML template. More...

bool	hasInternalPathEncoding () const
	Returns whether internal paths are enabled. More...

void	setEncodeTemplateText (bool on)
	Configures when internal path encoding is done. More...

bool	encodeTemplateText () const
	Returns whether internal path encoding is done on the template text. More...

virtual void	refresh () override
	Refresh the widget. More...

virtual void	renderTemplate (std::ostream &result)
	Renders the template into the given result stream. More...

bool	renderTemplateText (std::ostream &result, const WString &templateText)
	Renders a template into the given result stream. More...

std::string	getErrorText ()
	Renders the errors during renderring. More...

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...

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 void	setHidden (bool hidden, const WAnimation &animation=WAnimation()) override
	Hides or shows the widget. 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	setToolTip (const WString &text, TextFormat textFormat=TextFormat::Plain) override
	Sets a tooltip. 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	canReceiveFocus () const override
	Returns 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...

virtual int	tabIndex () const override
	Returns 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.

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	applyArguments (WWidget *w, const std::vector< WString > &args)
	Applies arguments to a resolved widget. More...

void	format (std::ostream &result, const std::string &s, TextFormat textFormat=TextFormat::Plain)
	Utility method to safely format an XHTML string. More...

void	format (std::ostream &result, const WString &s, TextFormat textFormat=TextFormat::Plain)
	Utility method to safely format an XHTML string. More...

virtual void	enableAjax () override
	Progresses to an Ajax-enabled widget. More...

void	reset ()
	Notifies the template that it has changed and must be rerendered. More...

Protected Member Functions inherited from Wt::WInteractWidget
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...

virtual void	render (WFlags< RenderFlag > flags) override
	Renders the widget. 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
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

A widget that renders an XHTML template.

The XHTML template may contain references to variables which replaced by strings are widgets.

Since the template text may be supplied by a WString, you can conveniently store the string in a message resource bundle, and make it localized by using WString::tr().

Placeholders (for variables and functions) are delimited by: ${...}. To use a literal "${", use "$${". Place holder names can contain '_', '-', '.' and alfanumeric characters.

Usage example:

WString userName = ...;
 
auto t = std::make_unique<WTemplate>();
t->setTemplateText("<div> How old are you, ${friend} ? ${age-input} </div>");
 
t->bindString("friend", userName, TextFormat::Plain);
ageEdit_ = t->bindWidget("age-input", std::make_unique<WLineEdit>());

There are currently three syntactic constructs defined: variable place holders, functions and conditional blocks.

A. Variable placeholders

${var} defines a placeholder for the variable "var", and gets replaced with whatever is bound to that variable:

a widget, using bindWidget()
a string value, using bindString() or bindInt()
or in general, the result of resolveString() and resolveWidget() methods.

Optionally, additional arguments can be specified using the following syntax:

${var arg1="A value" arg2='A second value'}

The arguments can thus be simple strings or quoted strings (single or double quoted). These arguments are applied to a resolved widget in applyArguments() and currently supports only style classes.

You can bind widgets and values to variables using bindWidget(), bindString() or bindInt() or by reimplementing the resolveString() and resolveWidget() methods.

Note: The use of XML comments () around variables that are bound to widgets will result in bad behaviour since the template parser is ignorant about these comments and the corresponding widgets will believe that they are rendered but aren't actually.

B. Functions

${fun:arg} defines a placeholder for applying a function "fun" to an argument "arg".

Optionally, additional arguments can be specified as with a variable placeholder.

Functions are resolved by resolveFunction(), and the default implementation considers functions bound with addFunction(). There are currently three functions that are generally useful:

: resolves a localized strings, this is convenient to create a language neutral template, which contains translated strings Functions::id : resolves the id of a bound widget, this is convenient to bind <label> elements to a form widget using its for attribute.
: recursively renders another string as macro block optional arguments substituted before processing template substitution. For example, the following template uses the "tr" function to translate the age-label using the "age-label" internationalized key. auto t = std::make_unique<WTemplate>(); t->addFunction("tr", &WTemplate::Functions::tr); t->setTemplateText("<div> ${tr:age-label} ${age-input} </div>"); ageEdit_ = t->bindWidget("age-input", std::make_unique<WLineEdit>()); C. Conditional blocks

${<cond>} starts a conditional block with a condition name "cond", and must be closed by a balanced ${</cond>}.

For example:

auto t = std::make_unique<WTemplate>();
t->setTemplateText("<div> ${<if-register>} Register ... ${</if-register>}</div>");
t->setCondition("if-register", true);

Conditions are set using setCondition().

The template can return a bound widget using resolve(), which already tries to cast the widget to the proper type.

CSS

This widget does not provide styling, and can be styled using inline or external CSS as appropriate.

Member Typedef Documentation

◆ Function

typedef std::function<bool(WTemplate *t, const std::vector<WString>& args, std::ostream& result)> Wt::WTemplate::Function

A function type.

See also: addFunction(); Functions::tr, Functions::id, Functions::block, Functions::while_f

Constructor & Destructor Documentation

◆ WTemplate()

Wt::WTemplate::WTemplate ( const WString & text )

Creates a template widget with given template.

The templateText must be proper XHTML, and this is checked unless the XHTML is resolved from a message resource bundle. This behavior is similar to a WText when configured with the Wt::TextFormat::XHTML textformat.

Member Function Documentation

◆ addFunction()

void Wt::WTemplate::addFunction	(	const std::string &	name,
		const Function &	function
	)

Binds a function.

Functions are useful to automatically resolve placeholders.

The syntax for a function 'fun' applied to a single argument 'bla' is:

${fun:bla}

There are three predefined functions, which can be bound using:

WTemplate *t = ...;
t->addFunction("id", &WTemplate::Functions::id);
t->addFunction("tr", &WTemplate::Functions::tr);
t->addFunction("block", &WTemplate::Functions::block);

◆ applyArguments()

void Wt::WTemplate::applyArguments	(	WWidget *	w,
		const std::vector< WString > &	args
	)

protectedvirtual

Applies arguments to a resolved widget.

Currently only a class argument is handled, which adds one or more style classes to the widget w, using WWidget::addStyleClass().

◆ bindEmpty()

void Wt::WTemplate::bindEmpty ( const std::string & varName )

Binds an empty string to a variable.

If a widget was bound to the variable, it is deleted first.

See also: bindString()

◆ bindInt()

void Wt::WTemplate::bindInt	(	const std::string &	varName,
		int	value
	)

Binds an integer value to a variable.

See also: bindString()

◆ bindNew()

template<typename Widget , typename ... Args>

Widget* Wt::WTemplate::bindNew	(	const std::string &	varName,
		Args &&...	args
	)

Creates a new widget with the given arguments, and binds it, returning a raw pointer.

This is implemented as:

std::unique_ptr<Widget> w{new Widget(std::forward<Args>(args)...)};
Widget *result = w.get();
bindWidget(varName, std::unique_ptr<WWidget>(std::move(w)));
return result;

This is a useful shorthand for creating and binding a widget in one go.

◆ bindString()

void Wt::WTemplate::bindString	(	const std::string &	varName,
		const WString &	value,
		TextFormat	textFormat = `TextFormat::XHTML`
	)

virtual

Binds a string value to a variable.

Each occurrence of the variable within the template will be substituted by its value.

Note: Depending on the textFormat, the value is validated according as for a WText. The default (TextFormat::XHTML) filters "active" content, to avoid XSS-based security risks.

See also: bindWidget(), bindInt(); resolveString(const std::string&)

◆ bindWidget() [1/2]

template<typename Widget >

Widget* Wt::WTemplate::bindWidget	(	const std::string &	varName,
		std::unique_ptr< Widget >	widget
	)

Binds a widget to a variable, returning a raw pointer.

This is implemented as:

Widget *result = widget.get();
bindWidget(varName, std::unique_ptr<WWidget>(std::move(widget)));
return result;

◆ bindWidget() [2/2]

void Wt::WTemplate::bindWidget	(	const std::string &	varName,
		std::unique_ptr< WWidget >	widget
	)

virtual

Binds a widget to a variable.

The corresponding variable reference within the template will be replaced with the widget (rendered as XHTML). Since a single widget may be instantiated only once in a template, the variable varName may occur at most once in the template, and the widget must not yet be bound to another variable.

The widget is reparented to the WTemplate, so that it is deleted when the WTemplate is deleted.

If a widget was already bound to the variable, it is deleted first. If previously a string or other value was bound to the variable, it is removed.

You may also pass a nullptr widget, which will resolve to an empty string.

See also: bindString(); resolveWidget()

◆ clear()

void Wt::WTemplate::clear ( )

virtual

Erases all variable bindings.

Removes all strings and deletes all widgets that were previously bound using bindString() and bindWidget().

This also resets all conditions set using setCondition(), but does not remove functions added with addFunction()

◆ conditionValue()

bool Wt::WTemplate::conditionValue ( const std::string & name ) const

virtual

Returns a condition value.

See also: setCondition()

◆ enableAjax()

void Wt::WTemplate::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.

◆ encodeTemplateText()

bool Wt::WTemplate::encodeTemplateText ( ) const

Returns whether internal path encoding is done on the template text.

See also: setEncodeTemplateText()

◆ format() [1/2]

void Wt::WTemplate::format	(	std::ostream &	result,
		const std::string &	s,
		TextFormat	textFormat = `TextFormat::Plain`
	)

protected

Utility method to safely format an XHTML string.

The string is formatted according to the indicated textFormat. It is recommended to use this method when specializing resolveString() to avoid security risks.

◆ format() [2/2]

void Wt::WTemplate::format	(	std::ostream &	result,
		const WString &	s,
		TextFormat	textFormat = `TextFormat::Plain`
	)

protected

Utility method to safely format an XHTML string.

The string is formatted according to the indicated textFormat. It is recommended to use this method when specializing resolveString() to avoid security risks.

◆ getErrorText()

std::string Wt::WTemplate::getErrorText ( )

Renders the errors during renderring.

See also: renderTemplateText()

◆ handleUnresolvedVariable()

void Wt::WTemplate::handleUnresolvedVariable	(	const std::string &	varName,
		const std::vector< WString > &	args,
		std::ostream &	result
	)

virtual

Handles a variable that could not be resolved.

This method is called from resolveString() for variables that could not be resolved.

The default implementation implementation writes "??" + varName + "??" to the result stream.

The result stream expects a UTF-8 encoded string value.

Warning: When specializing this class, you need to make sure that you append proper XHTML to the result, without unsafe active contents. The format() methods may be used for this purpose.

See also: resolveString()

◆ hasInternalPathEncoding()

bool Wt::WTemplate::hasInternalPathEncoding ( ) const

Returns whether internal paths are enabled.

See also: setInternalPathEncoding()

◆ refresh()

void Wt::WTemplate::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.

◆ removeWidget() [1/3]

std::unique_ptr< WWidget > Wt::WTemplate::removeWidget ( const std::string & varName )

Unbinds a widget by variable name.

This removes a previously bound widget and unbinds the corresponding variable, effectively undoing the effect of bindWidget().

If this template does not contain a widget for the given varName, nullptr is returned.

◆ removeWidget() [2/3]

template<typename Widget >

std::unique_ptr<Widget> Wt::WWidget::removeWidget ( typename Widget )

Removes a child widget.

This is an overload that automatically casts the returned value to a unique_ptr<Widget> for convenience

This is implemented as:

return std::unique_ptr<Widget>(static_cast<Widget*>(removeWidget(static_cast<WWidget*>(widget)).release()));

Wt::WTemplate::removeWidget

virtual std::unique_ptr< WWidget > removeWidget(WWidget *widget)

Removes a child widget.

Wt::WWidget::WWidget

WWidget()

Creates a widget.

Definition: WWidget.C:27

◆ removeWidget() [3/3]

std::unique_ptr< WWidget > Wt::WTemplate::removeWidget ( WWidget * widget )

overridevirtual

Unbinds a widget by widget pointer.

This removes a previously bound widget and unbinds the corresponding variable, effectively undoing the effect of bindWidget().

If this template does not contain the given widget, nullptr is returned.

Reimplemented from Wt::WWidget.

◆ renderTemplate()

void Wt::WTemplate::renderTemplate ( std::ostream & result )

virtual

Renders the template into the given result stream.

The default implementation will call renderTemplateText() with the templateText().

◆ renderTemplateText()

bool Wt::WTemplate::renderTemplateText	(	std::ostream &	result,
		const WString &	templateText
	)

Renders a template into the given result stream.

The default implementation will parse the template, and resolve variables by calling resolveString().

You may want to reimplement this method to manage resources that are needed to load content on-demand (e.g. database objects), or support a custom template language.

Return: true if rendered successfully.

See also: getErrorText()

◆ reset()

void Wt::WTemplate::reset ( )

protected

Notifies the template that it has changed and must be rerendered.

If you update a WTemplate with e.g bindWidget or setCondition, or change the template text, the template will automatically be rerendered.

However, if you create a subclass of WTemplate and override resolveString or resolveWidget, you will have to notify the WTemplate if it has changed with a call to reset().

◆ resolve()

template<typename T >

T Wt::WTemplate::resolve ( const std::string & varName )

Returns a widget for a variable name.

This is a convience method, which calls resolveWidget() and dynamic casts the result to type T. You may use this method to fetch widgets that have previously been bound using bindWidget().

If the cast fails, a null pointer is returned.

◆ resolveFunction()

bool Wt::WTemplate::resolveFunction	(	const std::string &	name,
		const std::vector< WString > &	args,
		std::ostream &	result
	)

virtual

Resolves a function call.

This resolves a function with name name, and one or more arguments args, and writes the result into the stream result. The method returns whether a function was matched and applied.

The default implementation considers functions that were bound using addFunction().

See also: addFunction()

◆ resolveString()

void Wt::WTemplate::resolveString	(	const std::string &	varName,
		const std::vector< WString > &	args,
		std::ostream &	result
	)

virtual

Resolves the string value for a variable name.

This is the main method used to resolve variables in the template text, during rendering.

The default implementation considers first whether a string was bound using bindString(). If so, that string is returned. If not, it will attempt to resolve a widget with that variable name using resolveWidget(), and render it as XHTML. If that fails too, handleUnresolvedVariable() is called, passing the initial arguments.

You may want to reimplement this method to provide on-demand loading of strings for your template.

The result stream expects a UTF-8 encoded string value.

Warning: When specializing this class, you need to make sure that you append proper XHTML to the result, without unsafe active contents. The format() methods may be used for this purpose.

See also: renderTemplate()

◆ resolveStringValue()

const WString & Wt::WTemplate::resolveStringValue ( const std::string & varName )

virtual

Resolves a string that was bound to a variable name.

Returns the string that was bound to the variable with bindString().

This method is not to be confused with resolveString(const std::string&, const std::vector<WString>&, std::ostream&) which resolves any variable to a string (both strings and widgets alike).

◆ resolveWidget()

WWidget * Wt::WTemplate::resolveWidget ( const std::string & varName )

virtual

Resolves a widget for a variable name.

The default implementation returns a widget that was bound using bindWidget().

You may want to reimplement this method to create widgets on-demand. All widgets that are returned by this method are reparented to the WTemplate, so they will be deleted when the template is destroyed, but they are not deleted by clear() (unless bind was called on them as in the example below).

This method is typically used for delayed binding of widgets. Usage example:

if (Wt::WWidget *known = WTemplate::resolveWidget(varName)) {
  return known;
} else {
  if (varName == "age-input") {
    // widget only created when used
    return bindWidget(varName, std::make_unique<Wt::WLineEdit>());
  }
  return nullptr;
}

◆ setCondition()

void Wt::WTemplate::setCondition	(	const std::string &	name,
		bool	value
	)

Sets a condition.

This enables or disables the inclusion of a conditional block.

The default value of all conditions is false.

◆ setEncodeTemplateText()

void Wt::WTemplate::setEncodeTemplateText ( bool on )

Configures when internal path encoding is done.

By default, the internal path encoding (if enabled) is done on the template text before placeholders are being resolved. In some rare situations, you may want to postpone the internal path encoding until after placeholders have been resolved, e.g. if a placeholder was used to provide the string for an anchor href.

The default value is true

◆ setInternalPathEncoding()

void Wt::WTemplate::setInternalPathEncoding ( bool enabled )

Enables internal path anchors in the XHTML template.

Anchors to internal paths are represented differently depending on the session implementation (plain HTML, Ajax or HTML5 history). By enabling this option, anchors which reference an internal path (by referring a URL of the form href="#/..."), are re-encoded to link to the internal path.

The default value is false.

See also: WAnchor::setRefInternalPath()

◆ setTemplateText()

void Wt::WTemplate::setTemplateText	(	const WString &	text,
		TextFormat	textFormat = `TextFormat::XHTML`
	)

Sets the template text.

The text must be proper XHTML, and this is checked unless the XHTML is resolved from a message resource bundle or TextFormat is Wt::TextFormat::UnsafeXHTML. This behavior is similar to a WText when configured with the Wt::TextFormat::XHTML textformat.

Changing the template text does not clear() bound widgets or values.

See also: clear()

◆ setWidgetIdMode()

void Wt::WTemplate::setWidgetIdMode ( TemplateWidgetIdMode mode )

Sets how the varName should be reflected on bound widgets.

To easily identify a widget in the browser, it may be convenient to reflect the varName, either through the object name (recommended) or the widget's ID.

The default value is TemplateWidgetIdMode::None which does not reflect the varName on the bound widget.

◆ templateText()

virtual WString Wt::WTemplate::templateText ( ) const

virtual

Returns the template.

See also: setTemplateText()

◆ widgetIdMode()

TemplateWidgetIdMode Wt::WTemplate::widgetIdMode ( ) const

Returns how the varName is reflected on a bound widget.

See also: setWidgetIdMode()

Classes

Public Types

Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

A. Variable placeholders

B. Functions

CSS

Member Typedef Documentation

◆ Function

Constructor & Destructor Documentation

◆ WTemplate()

Member Function Documentation

◆ addFunction()

◆ applyArguments()

◆ bindEmpty()

◆ bindInt()

◆ bindNew()

◆ bindString()

◆ bindWidget() [1/2]

◆ bindWidget() [2/2]

◆ clear()

◆ conditionValue()

◆ enableAjax()

◆ encodeTemplateText()

◆ format() [1/2]

◆ format() [2/2]

◆ getErrorText()

◆ handleUnresolvedVariable()

◆ hasInternalPathEncoding()

◆ refresh()

◆ removeWidget() [1/3]

◆ removeWidget() [2/3]

◆ removeWidget() [3/3]

◆ renderTemplate()

◆ renderTemplateText()

◆ reset()

◆ resolve()

◆ resolveFunction()

◆ resolveString()

◆ resolveStringValue()

◆ resolveWidget()

◆ setCondition()

◆ setEncodeTemplateText()

◆ setInternalPathEncoding()

◆ setTemplateText()

◆ setWidgetIdMode()

◆ templateText()

◆ widgetIdMode()