Wt  3.3.9
Public Types | Public Member Functions | List of all members
Wt::WFormModel Class Reference

A basic model class for forms. More...

#include <Wt/WFormModel>

Inheritance diagram for Wt::WFormModel:
Inheritance graph
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Public Types

typedef const char * Field
 A type to identify a field. More...
 
- Public Types inherited from Wt::WObject
typedef void(WObject::* Method) ()
 Typedef for a WObject method without arguments.
 

Public Member Functions

 WFormModel (WObject *parent=0)
 Constructor. More...
 
void addField (Field field, const WString &info=WString::Empty)
 Adds a field. More...
 
void removeField (Field field)
 Removes a field. More...
 
std::vector< Fieldfields () const
 Returns the fields. More...
 
virtual void reset ()
 Resets the model. More...
 
virtual bool validate ()
 Validates the current input. More...
 
bool valid () const
 Returns the current overall validation state. More...
 
void setVisible (Field field, bool visible)
 Sets whether a field is visible. More...
 
virtual bool isVisible (Field field) const
 Returns whether a field is visible. More...
 
void setReadOnly (Field field, bool readOnly)
 Sets whether a field is read-only. More...
 
virtual bool isReadOnly (Field field) const
 Returns whether a field is read only. More...
 
virtual WString label (Field field) const
 Returns a field label. More...
 
virtual void setValue (Field field, const boost::any &value)
 Sets the field value. More...
 
virtual const boost::any & value (Field field) const
 Returns the field value. More...
 
virtual WString valueText (Field field) const
 Returns the field value text. More...
 
virtual void setValidator (Field field, WValidator *validator)
 Sets a validator. More...
 
virtual WValidatorvalidator (Field field) const
 Returns a validator. More...
 
virtual bool validateField (Field field)
 Validates a field. More...
 
virtual void setValidated (Field field, bool validated)
 Sets whether a field has been validated. More...
 
virtual bool isValidated (Field field) const
 Returns whether the field has been validated yet. More...
 
const WValidator::Resultvalidation (Field field) const
 Returns the result of a validation. More...
 
virtual void setValidation (Field field, const WValidator::Result &result)
 Sets the validation result for a field. More...
 
- Public Member Functions inherited from Wt::WObject
 WObject (WObject *parent=0)
 Create a WObject with a given parent object. More...
 
virtual ~WObject ()
 Destructor. More...
 
virtual const std::string id () const
 Returns the (unique) identifier for this object. More...
 
virtual void setObjectName (const std::string &name)
 Sets an object name. 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...
 
void addChild (WObject *child)
 Adds a child object. More...
 
virtual void removeChild (WObject *child)
 Removes a child object. More...
 
const std::vector< WObject * > & children () const
 Returns the children.
 
WObjectparent () const
 Returns the parent object.
 

Additional Inherited Members

- Protected Member Functions inherited from Wt::WObject
virtual WStatelessSlot * getStateless (Method method)
 On-demand stateless slot implementation. More...
 
- Static Protected Member Functions inherited from Wt::WObject
static WObjectsender ()
 Returns the sender of the current slot call. More...
 

Detailed Description

A basic model class for forms.

This implements field data and validation handling for (simple) form-based views. It provides a standard way for views to perform field validation, and react to validation results.

All fields are uniquely identified using a string literal (which is the Field type). For each field, its value, the visibility, whether the field is read-only, and its current validation status is managed by the model. In addition, you will typically specialize the class to customize the validation and application logic.

Warning
The Field type is 'const char *, and instead of string comparisons to identify fields, pointer comparisons are used. Thus you really should use the same field constant throughout your code to refer to a given field, and you cannot use C++11 constexpr for the field constant since that does not have a unique value (since it has no storage).

Although it can be setup to use WValidator objects for individual fields, also other validation where more entered information needs to be considered simultaneously can be implemented.

A model is typically used by a View which renders the fields configured in the model, updates the model values, invokes and reflects the validation status.

Example (a bit contrived since you will usually not use the model directly):

Wt::WFormModel::Field NameField = "name";
Wt::WFormModel::Field TelField = "telephone";
model->addField(NameField, "Enter your name");
model->addField(TelField, "Phone number");
model->setValue(NameField, Wt::WString::fromUTF8("John Doe"));
if (model->validate()) {
...
} else {
const Wt::WValidator::Result& rname = model->validation(NameField);
if (rname.state() != Wt::WValidator::Valid) {
std::cerr <<< "Invalid name: " << rname.message();
}
...
}

Member Typedef Documentation

typedef const char* Wt::WFormModel::Field

A type to identify a field.

Fields are identified by a string literal constant.

Warning
Instead of string comparisons to identify fields, pointer comparisons are used. Thus you really should use the same field constant throughout your code to refer to a given field, and you cannot use C++11 constexpr for the field constant since that does not have a unique value (since it has no storage).

Constructor & Destructor Documentation

Wt::WFormModel::WFormModel ( WObject parent = 0)

Constructor.

Creates a new form model.

Member Function Documentation

void Wt::WFormModel::addField ( Field  field,
const WString info = WString::Empty 
)

Adds a field.

The field is added to the model, with an optional short informational message that can be used by views to provide a hint on the value that needs to be entered. The message is set as the validation message as long as the field has not yet been validated.

If the field was already in the model, its data is reset.

std::vector< WFormModel::Field > Wt::WFormModel::fields ( ) const

Returns the fields.

This returns the fields currently configured in the model (added with addField() or for which a value or property has been set).

bool Wt::WFormModel::isReadOnly ( Field  field) const
virtual

Returns whether a field is read only.

The default implementation returns the value set by setReadOnly()

Reimplemented in Wt::Auth::RegistrationModel.

bool Wt::WFormModel::isValidated ( Field  field) const
virtual

Returns whether the field has been validated yet.

This is initially false, and set to true by setValidation().

See also
setValidated()
bool Wt::WFormModel::isVisible ( Field  field) const
virtual

Returns whether a field is visible.

In some cases not all fields of the model need to be shown. This may depend on values input for certain fields, and thus change dynamically. You may specialize this method to indicate that a certain field should be invisible.

The default implementation returns the value set by setVisible().

Reimplemented in Wt::Auth::RegistrationModel, and Wt::Auth::AuthModel.

WString Wt::WFormModel::label ( Field  field) const
virtual

Returns a field label.

The default implementation returns the WString::tr(field)

Reimplemented in Wt::Auth::FormBaseModel.

void Wt::WFormModel::removeField ( Field  field)

Removes a field.

The field is removed from the model.

void Wt::WFormModel::reset ( )
virtual

Resets the model.

The default implementation clears the value of all fields, and resets the validation state to not validated.

Reimplemented in Wt::Auth::RegistrationModel, and Wt::Auth::AuthModel.

void Wt::WFormModel::setReadOnly ( Field  field,
bool  readOnly 
)

Sets whether a field is read-only.

Fields are read-write by default.

See also
isReadOnly()
void Wt::WFormModel::setValidated ( Field  field,
bool  validated 
)
virtual

Sets whether a field has been validated.

This is usually not used directly, but invoked by setValidation()

A field is initially (or after reset()), not validated.

void Wt::WFormModel::setValidation ( Field  field,
const WValidator::Result result 
)
virtual

Sets the validation result for a field.

This will also set the field as validated.

See also
validation(), isValidated()
void Wt::WFormModel::setValidator ( Field  field,
WValidator validator 
)
virtual

Sets a validator.

If the validator has no ownership yet, the form model will take ownership.

void Wt::WFormModel::setValue ( Field  field,
const boost::any &  value 
)
virtual

Sets the field value.

See also
value(), valueText()
void Wt::WFormModel::setVisible ( Field  field,
bool  visible 
)

Sets whether a field is visible.

Fields are visible by default. An invisible field will be ignored during validation (i.e. will be considered as valid).

See also
isVisible()
bool Wt::WFormModel::valid ( ) const

Returns the current overall validation state.

This checks the validation() of all fields, and returns true if all all fields have been validated and are valid.

See also
validate()
bool Wt::WFormModel::validate ( )
virtual

Validates the current input.

The default implementation calls validateField() for each field and returns true if all fields validated.

See also
validateField()

Reimplemented in Wt::Auth::AuthModel.

bool Wt::WFormModel::validateField ( Field  field)
virtual

Validates a field.

The default implementation uses the validator configured for the field to validate the field contents, or if no validator has been configured assumes that the field is valid.

You will typically customize this method for more complex validation cases.

See also
validate(), validationResult()

Reimplemented in Wt::Auth::RegistrationModel, and Wt::Auth::AuthModel.

const WValidator::Result & Wt::WFormModel::validation ( Field  field) const

Returns the result of a validation.

See also
validateField()
WValidator * Wt::WFormModel::validator ( Field  field) const
virtual

Returns a validator.

Returns the validator for the field.

const boost::any & Wt::WFormModel::value ( Field  field) const
virtual

Returns the field value.

See also
valueText(), setValue()
WString Wt::WFormModel::valueText ( Field  field) const
virtual

Returns the field value text.

This uses Wt::asString() to interpret the current value as text.

See also
value()

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