Class RelayCommand

A command whose sole purpose is to relay its functionality to other objects by invoking delegates. The default return value for the CanExecute(object?) method is true. This type does not allow you to accept command parameters in the Execute(object?) and CanExecute(object?) callback methods.

Inheritance

object

RelayCommand

Implements

IRelayCommand

ICommand

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: Unity.AppUI.MVVM

Assembly: Unity.AppUI.MVVM.dll

Syntax

public class RelayCommand : IRelayCommand, ICommand

Constructors

RelayCommand(Action?)

Initializes a new instance of the RelayCommand class.

Declaration

public RelayCommand(Action? execute)

Parameters

Type	Name	Description
Action	execute	The action to execute.

Exceptions

Type	Condition
ArgumentNullException	Thrown if the action is null.

RelayCommand(Action, Func<bool>)

Initializes a new instance of the RelayCommand class.

Declaration

public RelayCommand(Action execute, Func<bool> canExecute)

Parameters

Type	Name	Description
Action	execute	The action to execute.
Func<bool>	canExecute	Predicate used to determine if the command can execute.

Exceptions

Type	Condition
ArgumentNullException	Thrown if the action is null.

Methods

CanExecute()

Initializes a new instance of the RelayCommand class.

Declaration

public bool CanExecute()

Returns

Type	Description
bool	true if this command can be executed; otherwise, false.

CanExecute(object?)

Determines whether this RelayCommand can execute in its current state.

Declaration

public bool CanExecute(object? parameter)

Parameters

Type	Name	Description
object	parameter	Data used by the command.

Returns

Type	Description
bool	true if this command can be executed; otherwise, false.

Execute()

Defines the method to be called when the command is invoked.

Declaration

public void Execute()

Execute(object?)

Executes the RelayCommand on the current command target.

Declaration

public void Execute(object? parameter)

Parameters

Type	Name	Description
object	parameter	Data used by the command.

NotifyCanExecuteChanged()

Notifies that the CanExecuteChanged property has changed.

Declaration

public void NotifyCanExecuteChanged()

Events

CanExecuteChanged

Occurs when changes occur that affect whether or not the command should execute.

Declaration

public event EventHandler? CanExecuteChanged

Event Type

Type	Description
EventHandler

Implements

IRelayCommand

ICommand