xtd::forms::application_context Class Reference

Inheritance diagram for xtd::forms::application_context:

Definition

Specifies the contextual information about an application thread.

Header

#include <xtd/forms/application_context>

Namespace

xtd::forms

Library

xtd.forms

Remarks

You can use the application_context class to redefine the circumstances that cause a message loop to exit. By default, the application_context listens to the closed event on the application's main form, then exits the thread's message loop.

Examples

The following code example demonstrates the use of application and application_context classes.

#include <xtd/forms/application>
#include <xtd/forms/application_context>
#include <xtd/forms/form>
 
using namespace xtd::forms;
 
auto main() -> int {
  auto context = application_context {};
  
  auto form1 = form::create("Form 1 (Click the client area to set form as the main form)");
  form1.click += [&] {context.main_form(form1);};
  form1.show();
  
  auto form2 = form::create("Form 2 (Click the client area to set form as the main form)");
  form2.click += [&] {context.main_form(form2);};
  form2.show();
  
  auto form3 = form::create("Form 3 (Click the client area to set form as the main form)");
  form3.click += [&] {context.main_form(form3);};
  form3.show();
  
  // if no client area form clicked, the application will not exit when you close the forms.
  application::run(context);
}

Examples

application_context.cpp.

Protected Member Functions
virtual void	exit_thread_core ()
	Terminates the message loop of the thread.
virtual void	on_main_form_closed (object &sender, const event_args &e)
	Calls ExitThreadCore(), which raises the ThreadExit event.

Public Events
event< application_context, event_handler >	thread_exit
	Occurs when the message loop of the thread should be terminated, by calling exit_thread().

Public Constructors
	application_context ()
	Initializes a new instance of the application_context class with no context.
	application_context (const form &main_form) noexcept
	Initializes a new instance of the application_context class with the specified Form.

Public Properties
std::optional< const_form_ref >	main_form () const noexcept
	Gets the form to use as context.
std::optional< form_ref >	main_form () noexcept
	Gets or sets the Form to use as context.
void	main_form (const form &main_form)
	Sets the Form to use as context.
void	main_form (std::nullptr_t)
	Resets the Form to use as context.
std::any	tag () const noexcept
	Gets an object that contains data about the control.
void	tag (std::any tag)
	Sets an object that contains data about the control.

Public Methods
void	exit_thread ()
	Terminates the message loop of the thread.

Additional Inherited Members
Public Member Functions inherited from xtd::object
	object ()=default
	Create a new instance of the ultimate base class object.
virtual bool	equals (const object &obj) const noexcept
	Determines whether the specified object is equal to the current object.
virtual size_t	get_hash_code () const noexcept
	Serves as a hash function for a particular type.
virtual type_object	get_type () const noexcept
	Gets the type of the current instance.
template<typename object_t >
xtd::uptr< object_t >	memberwise_clone () const
	Creates a shallow copy of the current object.
virtual xtd::string	to_string () const noexcept
	Returns a xtd::string that represents the current object.
Static Public Member Functions inherited from xtd::object
template<typename object_a_t , typename object_b_t >
static bool	equals (const object_a_t &object_a, const object_b_t &object_b) noexcept
	Determines whether the specified object instances are considered equal.
template<typename object_a_t , typename object_b_t >
static bool	reference_equals (const object_a_t &object_a, const object_b_t &object_b) noexcept
	Determines whether the specified object instances are the same instance.

Constructor & Destructor Documentation

application_context() [1/2]

xtd::forms::application_context::application_context

(

)

Initializes a new instance of the application_context class with no context.

application_context() [2/2]

xtd::forms::application_context::application_context ( const form &  main_form )

explicitnoexcept

Initializes a new instance of the application_context class with the specified Form.

Parameters

main_form

The main form of the application to use for context.

Remarks

If on_main_form_closed is not overridden, the message loop of the thread terminates when main_form is closed.

Member Function Documentation

main_form() [1/4]

std::optional< const_form_ref > xtd::forms::application_context::main_form ( ) const

noexcept

Gets the form to use as context.

Returns

The form to use as context.

Remarks

This property determines the main form for this context. This property can change at any time. If on_main_form_closed is not overridden, the message loop of the thread terminates when the main_form parameter closes.

main_form() [2/4]

std::optional< form_ref > xtd::forms::application_context::main_form ( )

noexcept

Gets or sets the Form to use as context.

Returns

The form to use as context.

Remarks

This property determines the main form for this context. This property can change at any time. If on_main_form_closed is not overridden, the message loop of the thread terminates when the main_form parameter closes.

main_form() [3/4]

void xtd::forms::application_context::main_form

(

const form &

main_form

)

Sets the Form to use as context.

Parameters

main_form

The form to use as context.

Remarks

This property determines the main form for this context. This property can change at any time. If on_main_form_closed is not overridden, the message loop of the thread terminates when the main_form parameter closes.

main_form() [4/4]

void xtd::forms::application_context::main_form

(

std::nullptr_t

)

Resets the Form to use as context.

Parameters

nullptr

Remarks

This property determines the main form for this context. This property can change at any time. If on_main_form_closed is not overridden, the message loop of the thread terminates when the main_form parameter closes.

tag() [1/2]

std::any xtd::forms::application_context::tag ( ) const

noexcept

Gets an object that contains data about the control.

Returns

A std::any that contains data about the control. The default is empty.

Remarks

Any type of class can be assigned to this property.

A common use for the tag property is to store data that is closely associated with the control. For example, if you have a control that displays information about a customer, you might store a data_set that contains the customer's order history in that control's tag property so the data can be accessed quickly.

tag() [2/2]

void xtd::forms::application_context::tag

(

std::any

tag

)

Sets an object that contains data about the control.

Parameters

tag	A std::any that contains data about the control. The default is empty.

Remarks

Any type of class can be assigned to this property.

A common use for the tag property is to store data that is closely associated with the control. For example, if you have a control that displays information about a customer, you might store a data_set that contains the customer's order history in that control's tag property so the data can be accessed quickly.

exit_thread()

void xtd::forms::application_context::exit_thread

(

)

Terminates the message loop of the thread.

Remarks

This method calls exit_thread_core.

Note

exit_thread and exit_thread_core do not actually cause the thread to terminate. These methods raise the thread_exit event to which the Application object listens. The Application object then terminates the thread.

exit_thread_core()

virtual void xtd::forms::application_context::exit_thread_core ( )

protectedvirtual

Terminates the message loop of the thread.

Remarks

This method is called from exit_thread.

Note

exit_thread and exit_thread_core do not actually cause the thread to terminate. These methods raise the thread_exit event to which the Application object listens. The Application object then terminates the thread.

on_main_form_closed()

virtual void xtd::forms::application_context::on_main_form_closed ( object &  sender, const event_args &  e  )

protectedvirtual

Calls ExitThreadCore(), which raises the ThreadExit event.

Parameters

sender	The object that raised the event.
e	The event_args that contains the event data.

Remarks

The default implementation of this method calls exit_thread_core.

Member Data Documentation

thread_exit

event<application_context, event_handler> xtd::forms::application_context::thread_exit

Occurs when the message loop of the thread should be terminated, by calling exit_thread().

Remarks

For more information about handling events, see Handling and Raising Events.

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The documentation for this class was generated from the following file:

• xtd.forms/include/xtd/forms/application_context.h