Encapsulate Event

• Jun 07, 2019
• 3 minutes to read

Wraps access to a field’s event in a new event exposed in the active class.

Availability

Available from the context menus or via shortcuts:

• when the edit cursor or caret is on a field declaration, provided that the field type contains events.

Example

C#

public class ClassA
{
    // delegates...
    public delegate void MyEventHandler(object sender, EventArgs ea);

    // constructor...
    public ClassA(int a, int b)
    {
        A = a;
        B = b;
    }

    // public properties...
    public int A { get; set; }
    public int B { get; set; }

    // public methods...
    public int SumAB()
    {
        if (ABSummed != null)
            ABSummed(this, EventArgs.Empty);
        return A + B;
    }

    // public events...
    public event MyEventHandler ABSummed;
}

class EncapsulateEvent
{
    ClassA │objVar;
}

VB.NET

Public Class ClassA
    ' delegates
    Public Delegate Sub MyEventHandler(ByVal sender As Object, ByVal ea As EventArgs)

    ' private fields...
    Private _A As Integer
    Private _B As Integer

    ' constructor...
    Public Sub New(ByVal A As Integer, ByVal B As Integer)
        _A = A
        _B = B
    End Sub

    ' public properties...
    Public Property A() As Integer
        Get
            Return _A
        End Get
        Set(ByVal value As Integer)
            _A = value
        End Set
    End Property
    Public Property B() As Integer
        Get
            Return _B
        End Get
        Set(ByVal value As Integer)
            _B = value
        End Set
    End Property

    ' public methods...
    Public Function SumAB() As Integer
        RaiseEvent ABSummed(Me, EventArgs.Empty)

        Return A + B
    End Function

    ' public events...
    Public Event ABSummed As MyEventHandler
End Class

Class EncapsulateEvent
    Private │objVar As ClassA
End Class

Result:

C#

public class ClassA
{
    // delegates...
    public delegate void MyEventHandler(object sender, EventArgs ea);

    // constructor...
    public ClassA(int a, int b)
    {
        A = a;
        B = b;
    }

    // public properties...
    public int A { get; set; }
    public int B { get; set; }

    // public methods...
    public int SumAB()
    {
        if (ABSummed != null)
            ABSummed(this, EventArgs.Empty);
        return A + B;
    }

    // public events...
    public event MyEventHandler ABSummed;
}

class EncapsulateEvent
{
    public event ClassA.MyEventHandler ObjVarABSummed
    {
        add
        {
            objVar.ABSummed += value;
        }
        remove
        {
            objVar.ABSummed -= value;
        }
    }
    ClassA objVar;
}

VB.NET

Public Class ClassA
    ' delegates
    Public Delegate Sub MyEventHandler(ByVal sender As Object, ByVal ea As EventArgs)

    ' private fields...
    Private _A As Integer
    Private _B As Integer

    ' constructor...
    Public Sub New(ByVal A As Integer, ByVal B As Integer)
        _A = A
        _B = B
    End Sub

    ' public properties...
    Public Property A() As Integer
        Get
            Return _A
        End Get
        Set(ByVal value As Integer)
            _A = value
        End Set
    End Property
    Public Property B() As Integer
        Get
            Return _B
        End Get
        Set(ByVal value As Integer)
            _B = value
        End Set
    End Property

    ' public methods...
    Public Function SumAB() As Integer
        RaiseEvent ABSummed(Me, EventArgs.Empty)

        Return A + B
    End Function

    ' public events...
    Public Event ABSummed As MyEventHandler
End Class

Class EncapsulateEvent
    Public Custom Event ObjVarABSummed As ClassA.MyEventHandler
        AddHandler(ByVal value As ClassA.MyEventHandler)
            AddHandler objVar.ABSummed, value
        End AddHandler
        RemoveHandler(ByVal value As ClassA.MyEventHandler)
            RemoveHandler objVar.ABSummed, value
        End RemoveHandler
        RaiseEvent(ByVal sender As Object, ByVal ea As System.EventArgs)

        End RaiseEvent
    End Event
    Private objVar As ClassA
End Class

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