"Dirtied Form" in VB.NET

My data entry screen contains data controls, a listbox (ListView) that contains all records in the data table, and action buttons (OK/Save, Cancel/Undo, Delete and Exit/Close form). The user can directly add new records or select existing records to modify or delete. See below:

What is needed:

• For all TextBoxes:
  1. A custom TextBox control that Inherits System.Windows.Forms.TextBox
  2. I named the custom control: MyTextBox
  3. A ReadOnly Boolean property is added and named “TextAltered”
• For all MaskedTextBoxes:
  1. A custom MaskedTextBox control is needed that Inherits System.Windows.Forms.MaskedTextBox
  2. I named the custom control: MyMaskedTextBox 
  3. A ReadOnly Boolean property is added and named “TextAltered”
• If a Listbox(ListView) picklist is used to select a record to populate a form with existing data , then code at the end of the code in the control event ListViewPickList_SelectedIndexChanged.
• A private property in the data entry form named FormIsDirty which is placed in the code button for closing the form or in the event when the form is closed.
• After MyTextBox and MyMaskedTextBox classes create the new controls, use these controls in your data entry form. They will be found in your Toolbox (search for “My”)
• Below, you will see the newly-created property of MyTextBox:

Public Class MyTextBox

    Inherits System.Windows.Forms.TextBox

    Private Property OriginalValue As String = ""

    Public ReadOnly Property OriginalText As String

        Get

            Return Me.OriginalValue

        End Get

    End Property

    Public ReadOnly Property TextAltered As Boolean

        Get

            If Me.OriginalValue Is Nothing And MyBase.Text Is Nothing Then

                Return False

            ElseIf Me.OriginalValue Is Nothing Or MyBase.Text Is Nothing Then

                Return True

            Else

                Return Not Me.OriginalValue.Equals(MyBase.Text)

            End If

        End Get

    End Property

    Public Sub Reset()

        Me.OriginalValue = MyBase.Text

    End Sub

End Class

Public Class MyMaskedTextBox

    Inherits System.Windows.Forms.MaskedTextBox

    Private Property OriginalValue As String = "(   )    -"

    Public ReadOnly Property OriginalText As String

        Get

            Return Me.OriginalValue

        End Get

    End Property

    Public ReadOnly Property TextAltered As Boolean

        Get

            If Me.OriginalValue Is Nothing And MyBase.Text Is Nothing Then

                Return False

            ElseIf Me.OriginalValue Is Nothing Or MyBase.Text Is Nothing Then

                Return True

            Else

                Return Not Me.OriginalValue.Equals(MyBase.Text)

            End If

        End Get

    End Property

    Public Sub Reset()

        Me.OriginalValue = MyBase.Text

    End Sub

End Class

SPECIAL NOTE: 

In the case of the MaskedTextBox, the setting of Private Property OriginalValue As String conforms to the mask that you intend to use. In this case, it is for telephone number.

If a Listbox(ListView) picklist is used to select a record to populate a form with existing data , then code at the end of the code in the control event ListViewPickList_SelectedIndexChanged. (The Reset() is part of the MyTextBox and MyMaskedTextBox classes.)

Code to be added 

            Me.sFirstName.Reset()

            Me.sLastName.Reset()

            Me.sSpouseName.Reset()

            Me.sAddress.Reset()

            Me.sCity.Reset()

            Me.sState.Reset()

            Me.sPostalCode.Reset()

            Me.sEmailAddress.Reset()

            Me.sLandLinePhone.Reset()

            Me.sMobilePhone.Reset()

A private property in the data entry form named FormIsDirty which is placed in the code button for closing the form or in the event when the form is closed.

   Private ReadOnly Property FormIsDirty As Boolean

        Get

            Return Me.sFirstName.TextAltered Or

              Me.sLastName.TextAltered Or

              Me.sSpouseName.TextAltered Or

              Me.sAddress.TextAltered Or

              Me.sCity.TextAltered Or

              Me.sState.TextAltered Or

              Me.sPostalCode.TextAltered Or

              Me.sEmailAddress.TextAltered Or

              Me.sLandLinePhone.TextAltered Or

              Me.sMobilePhone.TextAltered

        End Get

    End Property

This is how the FormIsDirty property is used. In this case, a button closes the form but the code could be used in the FormClosed or FormClosing event.

Private Sub btnExit_Click(sender As Object, e As EventArgs) Handles btnExit.Click

If FormIsDirty Then

iUserResponse = MsgBox("Data on this screen has changed but is not being saved!" & vbCrLf & vbCrLf & "Do you want to save these changes?", vbYesNo + vbQuestion)

If iUserResponse = vbYes Then 

btnOK_Click(btnOK, New EventArgs())

      Else

         MsgBox("The data was not saved.", vbOKOnly + vbExclamation, sTitle)

      End If

End If

Me.Close()

End Sub

 Private Sub ResetTextAlteredAttribute()
        Me.sFirstName.Reset()
        Me.sLastName.Reset()
        Me.sSpouseName.Reset()
        Me.sAddress.Reset()
        Me.sCity.Reset()
        Me.sState.Reset()
        Me.sPostalCode.Reset()
        Me.sEmailAddress.Reset()
        Me.sLandLinePhone.Reset()
        Me.sMobilePhone.Reset()
    End Sub