Everything You Wanted to Know About Forms Inheritance in VB.Net

If you simply inherit the form, you will not be able to change the properties of the Controls which you have placed in the base form. This example covers:

1. How to inherit the form
2. How make custom properties
3. How to use the custom properties from the Child form
4. How you change the properties of the controls from the parent form, which are not in the parent form (i.e. they are in the Child forms)
5. How to override the functionality of the Parent form from the Child Form
6. How to change the properties of the inherited controls at design time (i.e. how to reposition the controls, set different properties, etc.)

1) How to inherit the form

Open the child form and replace the ChildForm’s Inherits line to <name of the parent form> from <System.Windows.Forms.Form>

Base Form:
Public Class PMainForm
    Inherits System.Windows.Forms.Form

Child Forms:
Public Class ChildForm
    Inherits PmainForm

2) How to make custom properties

Open the Parent Form and create a property (having a scope as Protected Friend)

    'CurrentPosition Property
    Dim LPosition As Long
    Protected Property Position() As Long
        Get
            Return LPosition
        End Get
        Set(ByVal Value As Long)
            LPosition = Value
        End Set
    End Property

3) How to use the custom properties from the Child form

Open the child Form. Use Me.<propertyName> to change the property. For example, we are changing the property in the Load event of the child form.