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
Inherited Members
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<T> 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<T> 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