« Read-Only » and « Write-Only » Properties with Excel VBA

VBA allows you to create both read-only properties (i.e., those that can only retrieve data) and write-only properties (i.e., those that can only assign values).

When declaring a read-only property, there is no need to define a Property Let or Property Set procedure. When declaring a write-only property, the Property Get block is omitted.

In the following example, a class Point is created.

• The properties GetX and GetY are read-only properties that allow reading the values of the fields.
• The properties SetX and SetY are write-only properties intended for assigning values to the fields.

Additionally, the class defines a ToString() method for outputting general information about the class instance as a string.

« Read-only » and « Write-only » properties. Class module Point

Private x As Integer
Private y As Integer

Public Property Get GetX() As String
    GetX = x
End Property

Public Property Let SetX(ByRef valX As String)
    x = valX
End Property

Public Property Get GetY() As String
    GetY = y
End Property

Public Property Let SetY(ByRef valY As String)
    y = valY
End Property

Public Function ToString() As String
    ToString = "(" & x & "," & y & ")"
End Function

« Read-only » and « Write-only » properties. Standard module

Sub DemoOnlyProperties()
    Dim p As New Point
    p.SetX = 1 : p.SetY = 4
    Debug.Print p.ToString
    Debug.Print p.GetX & vbTab & p.GetY
End Sub