Visual Basic でのBindableBase

BindableBase.vb

Public MustInherit Class BindableBase : Implements INotifyPropertyChanged

    Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged

    Protected Function SetProperty(Of t)(ByRef storage As t, value As t, Optional propertyName As String = Nothing) As Boolean
        If Object.Equals(storage, value) Then Return False

        storage = value
        Me.OnPropertyChanged(propertyName)
        Return True
    End Function

    Protected Sub OnPropertyChanged(Optional propertyName = Nothing)
        RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propertyName))
    End Sub

End Class

DelegateCommand 

Public Class DelegateCommand : Implements ICommand

    Private _execute As Action(Of Object)

    Private _canExecute As Func(Of Object, Boolean)

    Public Sub New(execute As Action(Of Object))
        Me._execute = execute
        Me._canExecute = Nothing
    End Sub

    Public Sub New(execute As Action(Of Object), canExecute As Func(Of Object, Boolean))
        Me._execute = execute
        Me._canExecute = canExecute
    End Sub

    Public Event CanExecuteChanged As EventHandler Implements ICommand.CanExecuteChanged

    Public Sub RaiseCanExecuteChanged()
        RaiseEvent CanExecuteChanged(Me, EventArgs.Empty)
    End Sub

    Public Sub Execute(parameter As Object) Implements ICommand.Execute
        If (Me._execute IsNot Nothing) Then Me._execute(parameter)
    End Sub

    Public Function CanExecute(parameter As Object) As Boolean Implements ICommand.CanExecute
        Return If(Me._canExecute IsNot Nothing, Me._canExecute(parameter), True)
    End Function

End Class