Class DelegateCommandBase

Inheritance

System.Object

DelegateCommandBase

DelegateCommand

DelegateCommand<T>

Implements

System.Windows.Input.ICommand

IActiveAware

Inherited Members

System.Object.Equals(System.Object)

System.Object.Equals(System.Object, System.Object)

System.Object.GetHashCode()

System.Object.GetType()

System.Object.MemberwiseClone()

System.Object.ReferenceEquals(System.Object, System.Object)

System.Object.ToString()

Namespace: Sartorius.SAF.Presentation.Commands

Assembly: Sartorius.SAF.Presentation.dll

Syntax

public abstract class DelegateCommandBase : ICommand, IActiveAware

Constructors

DelegateCommandBase(Action<Object>, Func<Object, Boolean>)

Create a new instance of a DelegateCommandBase, specifying both the execute action and the can execute function.

Declaration

protected DelegateCommandBase(Action<object> executeMethod, Func<object, bool> canExecuteMethod)

Parameters

Type	Name	Description
System.Action<System.Object>	executeMethod	The System.Action to execute when System.Windows.Input.ICommand.Execute(System.Object) is invoked.
System.Func<System.Object, System.Boolean>	canExecuteMethod	The System.Func<T, TResult> to invoked when System.Windows.Input.ICommand.CanExecute(System.Object) is invoked.

Properties

IsActive

Gets or sets a value indicating whether the object is active.

Declaration

public bool IsActive { get; set; }

Property Value

Type	Description
System.Boolean	true if the object is active; otherwise false.

Methods

CanExecute(Object)

Determines if the command can execute with the provided parameter by invoking the System.Func<T, TResult> supplied during construction.

Declaration

protected bool CanExecute(object parameter)

Parameters

Type	Name	Description
System.Object	parameter	The parameter to use when determining if this command can execute.

Returns

Type	Description
System.Boolean	Returns true if the command can execute. langword_csharp_False otherwise.

Execute(Object)

Executes the command with the provided parameter by invoking the System.Action<T> supplied during construction.

Declaration

protected void Execute(object parameter)

Parameters

Type	Name	Description
System.Object	parameter

OnCanExecuteChanged()

Raises System.Windows.Input.ICommand.CanExecuteChanged on the UI thread so every command invoker can re-query System.Windows.Input.ICommand.CanExecute(System.Object) to check if the command can execute.

Declaration

protected virtual void OnCanExecuteChanged()

OnIsActiveChanged()

This raises the IsActiveChanged event.

Declaration

protected virtual void OnIsActiveChanged()

RaiseCanExecuteChanged()

Raises CanExecuteChanged on the UI thread so every command invoker can query to check if the command can execute. Note that this will trigger the execution of CanExecute(Object) once for each invoker.

Declaration

public void RaiseCanExecuteChanged()

Events

CanExecuteChanged

Occurs when changes occur that affect whether or not the command should execute. You must keep a hard reference to the handler to avoid garbage collection and unexpected results. See remarks for more information.

Declaration

public event EventHandler CanExecuteChanged

Event Type

Type	Description
System.EventHandler

Remarks

When subscribing to the System.Windows.Input.ICommand.CanExecuteChanged event using code (not when binding using XAML) will need to keep a hard reference to the event handler. This is to prevent garbage collection of the event handler because the command implements the Weak Event pattern so it does not have a hard reference to this handler. An example implementation can be seen in the CompositeCommand and CommandBehaviorBase classes. In most scenarios, there is no reason to sign up to the CanExecuteChanged event directly, but if you do, you are responsible for maintaining the reference.

Examples

The following code holds a reference to the event handler. The myEventHandlerReference value should be stored in an instance member to avoid it from being garbage collected.

EventHandler myEventHandlerReference = new EventHandler(this.OnCanExecuteChanged);
command.CanExecuteChanged += myEventHandlerReference;

IsActiveChanged

Fired if the IsActive property changes.

Declaration

public virtual event EventHandler IsActiveChanged

Event Type

Type	Description
System.EventHandler

Explicit Interface Implementations

ICommand.CanExecute(Object)

Declaration

bool ICommand.CanExecute(object parameter)

Parameters

Type	Name	Description
System.Object	parameter

Returns

Type	Description
System.Boolean

ICommand.Execute(Object)

Declaration

void ICommand.Execute(object parameter)

Parameters

Type	Name	Description
System.Object	parameter

Implements

System.Windows.Input.ICommand

IActiveAware

Extension Methods

CollectionExtensions.AddRange<T, TCollection>(TCollection, IEnumerable<T>)

SerializableObjectCloneExtension.Clone<T>(T)