Classes that implement Wt's model/view system. More...

Classes
struct	Wt::any_traits< Type >
	A traits class for a type stored in a cpp17::any. More...

class	Wt::ItemDataRole
	Enumeration that indicates a role for a data item. More...

class	Wt::Chart::WAbstractChart
	Abstract base class for MVC-based charts. More...

class	Wt::Chart::WCartesianChart
	A cartesian chart. More...

class	Wt::Chart::WPieChart
	A pie chart. More...

class	Wt::Dbo::QueryModel< Result >
	A Wt MVC Model to view/edit query results. More...

class	Wt::WAbstractItemDelegate
	Abstract delegate class for rendering an item in an item view. More...

class	Wt::WAbstractItemModel
	An abstract model for use with Wt's view classes. More...

class	Wt::WAbstractItemView
	An abstract base class for item Views. More...

class	Wt::WAbstractListModel
	An abstract list model for use with Wt's view classes. More...

class	Wt::WAbstractProxyModel
	An abstract proxy model for Wt's item models. More...

class	Wt::WAbstractTableModel
	An abstract table model for use with Wt's view classes. More...

class	Wt::WAggregateProxyModel
	A proxy model for Wt's item models that provides column aggregation. More...

class	Wt::WBatchEditProxyModel
	A proxy model for Wt's item models that provides batch editing. More...

class	Wt::WComboBox
	A widget that provides a drop-down combo-box control. More...

class	Wt::WItemDelegate
	Standard delegate class for rendering a view item. More...

class	Wt::WItemSelectionModel
	A class that represents a selection for a WAbstractItemView. More...

class	Wt::WModelIndex
	A value class that describes an index to an item in a data model. More...

class	Wt::WReadOnlyProxyModel
	A read-only wrapper for a source model. More...

class	Wt::WSelectionBox
	A selection box allows selection from a list of options. More...

class	Wt::WSortFilterProxyModel
	A proxy model for Wt's item models that provides filtering and/or sorting. More...

class	Wt::WStandardItem
	An item in a WStandardItemModel. More...

class	Wt::WStandardItemModel
	A standard data model, which stores its data in memory. More...

class	Wt::WStringListModel
	An model that manages a list of strings. More...

class	Wt::WSuggestionPopup
	A widget which popups to assist in editing a textarea or lineedit. More...

class	Wt::WTableView
	An MVC View widget for tabular data. More...

class	Wt::WTreeView
	A view class that displays a model as a tree or tree table. More...

Enumerations
enum class	Wt::MatchFlag { Wt::Exactly = 0x0 , Wt::StringExactly = 0x1 , Wt::StartsWith = 0x2 , Wt::EndsWith = 0x3 , Wt::RegExp = 0x4 , Wt::WildCard = 0x5 , Wt::CaseSensitive = 0x10 , Wt::Wrap = 0x20 }
	Flags that specify how to match two values. More...

enum class	Wt::HeaderFlag { Wt::ColumnIsCollapsed = 0x1 , Wt::ColumnIsExpandedLeft = 0x2 , Wt::ColumnIsExpandedRight = 0x4 , Wt::UserCheckable = 0x8 , Wt::Tristate = 0x10 , Wt::XHTMLText = 0x40 }
	Flags that indicate table header options. More...

enum class	Wt::ItemFlag { Wt::Selectable = 0x1 , Wt::Editable = 0x2 , Wt::UserCheckable = 0x4 , Wt::DragEnabled = 0x8 , Wt::DropEnabled = 0x10 , Wt::Tristate = 0x20 , Wt::XHTMLText = 0x40 , Wt::Dirty = 0x80 , Wt::DeferredToolTip = 0x100 }
	Flags that indicate data item options. More...

enum class	Wt::SortOrder { Wt::Ascending , Wt::Descending }
	Enumeration that indicates a sort order. More...

enum class	Wt::DropAction { Wt::Copy = 0x1 , Wt::Move = 0x2 }
	Enumeration that indicates a drop action. More...

Functions
WString	Wt::asString (const cpp17::any &v, const WString &formatString=WString())
	Interprets a cpp17::any as a string value. More...

double	Wt::asNumber (const cpp17::any &v)
	Interprets a cpp17::any as a number value. More...

template<typename Type >
void	Wt::registerType ()
	Registers MVC-support for a type passed in a cpp17::any. More...

Detailed Description

Classes that implement Wt's model/view system.

1. Models

The library provides support for tabular, tree-like and tree-table like models. All of these implement WAbstractItemModel.

Concrete model implementations

The following concrete model implementations are provided:

Wt::WStandardItemModel: a full general purpose model, which stores data in memory.
Wt::WStringListModel: a low-height single column model, useful for simple list views
Wt::Dbo::QueryModel: a database query backed model

Proxy model implementations

Proxy models are helper models which wrap around another model, to provide additional functionality on top of the existing model. The following propy models:

Wt::WSortFilterProxyModel: provides sorting and filtering support
Wt::WAggregateProxyModel: provides column aggregation (useful only for views that implement column aggregation such as WAbstractItemView's).

Abstract models

Abstract models cannot be instantiated as such, but are the base point for custom model implementations:

Wt::WAbstractItemModel: abstract base class of all models
Wt::WAbstractTableModel: abstract base class for tabular models
Wt::WAbstractProxyModel: abstract base class for proxy models.

2. Views

Item-based views

WComboBox: a combo box
WSelectionBox: a selection box
WTableView: a table view (with editing support)
WTreeView: a tree(-table) view (with editing support)
WSuggestionPopup: an intelligent input-driven combo box

Graphical views

Chart::WCartesianChart: 2D cartesian chart
Chart::WPieChart: pie charts

3. Helper classes

Model indexes

WModelIndex represents an index to an item of a WAbstractItemModel, identified by a row, column and parent node.

Item delegates

Item delegates are used by WTableView and WTreeView to render a single item and to provide editing support.

The abstract base class is WAbstractItemDelegate, and a default implementation is provided by WItemDelegate.

Enumeration Type Documentation

◆ DropAction

enum Wt::DropAction

strong

Enumeration that indicates a drop action.

See also: WAbstractItemModel::dropEvent()

Enumerator
Copy	Copy the selection.
Move	Move the selection (deleting originals)

◆ HeaderFlag

enum Wt::HeaderFlag

strong

Flags that indicate table header options.

See also: WAbstractItemModel::headerFlags()

Enumerator
ColumnIsCollapsed	Flag that indicates that the column can be expanded. See also WAbstractItemModel::expandColumn()
ColumnIsExpandedLeft	Flag that indicates that the column was expanded to the left. See also WAbstractItemModel::collapseColumn()
ColumnIsExpandedRight	Flag that indicates that the column was expanded to the right. See also WAbstractItemModel::collapseColumn()
UserCheckable	Flag that indicates that the header can be checked.
Tristate	Flag that indicates that the item has three states. When set, Wt::ItemDataRole::Checked data is of type Wt::CheckState
XHTMLText	Flag that indicates that the item text (ItemDataRole::Display, ItemDataRole::ToolTip) is HTML.

◆ ItemFlag

enum Wt::ItemFlag

strong

Flags that indicate data item options.

See also: WModelIndex::flags()

Enumerator
Selectable	Item can be selected.
Editable	Item can be edited.
UserCheckable	Item can be checked (checkbox is enabled)
DragEnabled	Item can be dragged.
DropEnabled	Item can be a drop target.
Tristate	Item has tree states. When set, Wt::ItemDataRole::Checked data is of type Wt::CheckState
XHTMLText	Item's text (ItemDataRole::Display, ItemDataRole::ToolTip) is HTML.
Dirty	Item's value has been modified.
DeferredToolTip	Item's tooltip is deferred.

◆ MatchFlag

enum Wt::MatchFlag

strong

Flags that specify how to match two values.

Except when MatchFlag::Exactly, the lexical matching is done (by comparing string representations of the value with the query). This is by default case insensitive, unless MatchFlag::CaseSensitive is OR'ed.

Enumerator
Exactly	Same type and value.
StringExactly	Lexical match.
StartsWith	Match start with query.
EndsWith	Match end with query.
RegExp	Regular expression match.
WildCard	Wildcard match.
CaseSensitive	Case sensitive.
Wrap	Wrap around whole model.

◆ SortOrder

enum Wt::SortOrder

strong

Enumeration that indicates a sort order.

Enumerator
Ascending	Ascending sort order.
Descending	Descending sort order.

Function Documentation

◆ asNumber()

double Wt::asNumber ( const cpp17::any & v )

Interprets a cpp17::any as a number value.

The conversion works as follows:

A cpp17::any without a value, or a string that does not represent a number, is converted to a NaN.
A string is lexically casted to a double
Data of type WDate is converted to an integer number using WDate::toJulianDay().
Data of type WDateTime is converted to an integer number using WDateTime::toTime_t().
Data of type WTime is converted to an integer number as the number of milliseconds since midnight.

Other types are converted according to Wt::any_traits<Type>::asNumber(). For these other types, you need to register their support first using Wt::registerType<Type>() and you may want to specialize Wt::any_traits<Type> for a custom handling of their conversions.

See also: asString(), any_traits

◆ asString()

WString Wt::asString	(	const cpp17::any &	v,
		const WString &	formatString = `WString()`
	)

Interprets a cpp17::any as a string value.

The conversion works as follows:

A cpp17::any without a value is converted to an empty string
Number values (integers and doubles) are formatted using the format string with snprintf(), or with std::stod() if the format string is empty.
Data of type WDate is converted with WDate::toString() using the indicated format string. If the format string is empty, WLocalce::currentLocale().dateFormat() is assumed.
Data of type WTime is converted with WTime::toString() using the indicated format string. If the format string is emtpy, WLocale::currentLocale().timeFormat() is assumed.
Data of type WDateTime is converted with WDateTime::toString() using the indicated format string. If the format string is empty, WLocale::currentLocale().dateTimeFormat() is assumed.

Other types are converted according to Wt::any_traits<Type>::asString(). For these other types, you need to register their support first using Wt::registerType<Type>() and you may want to specialize Wt::any_traits<Type> for a custom handling of their conversions.

See also: asNumber(), any_traits

◆ registerType()

template<typename Type >

void Wt::registerType ( )

Registers MVC-support for a type passed in a cpp17::any.

By registering a type using this method, the global function Wt::asString(), which converts a cpp17::any to a string, will know how to interpret a cpp17::any holding a value of type Type using Wt::any_traits<Type>::asString(). This gives Wt's built-in standard View classes the ability to display Wt::ItemDataRole::Display data of a Wt::WAbstractItemModel model.

Similarly, Wt::asNumber() uses Wt::any_traits<Type>::asNumber() for use by Wt::Chart::WCartesianChart and Wt::Chart::WPieChart as numerical data.

The default implementation of Wt::any_traits<Type> converts a value t to a Wt::WString by using std::ostream<<, expecting a UTF-8 string. This conversion thus relies on the std::ostream<< operator to be overloaded for the type. You may want to specialize Wt::any_traits to provide a custom conversion for a type, or if you want to take into account the format string.

The following types are registered by Wt itself:

strings of type WString or std::string
WDate, WTime, WDateTime
standard C++ numeric types (int, double, etc...)
bool

This method is thread-safe, and it is not an error to register the same type multiple times.

Classes

Enumerations

Functions

Detailed Description

1. Models

Concrete model implementations

Proxy model implementations

Abstract models

2. Views

Item-based views

Graphical views

3. Helper classes

Model indexes

Item delegates

Enumeration Type Documentation

◆ DropAction

◆ HeaderFlag

◆ ItemFlag

◆ MatchFlag

◆ SortOrder

Function Documentation

◆ asNumber()

◆ asString()

◆ registerType()