DataTable RowChanged Events raised for rows that have not changed when using DataTable.Merge(DataTable)

Question

I had to accept the fact that the RowChange event is raised for every row during the DataTable Merge. This means that I couldn't use the RowChange Event to raise an event for my business classes to handle (which would then raise change notification events that refresh the UI when applicable).

To solve my problem I:

Copy the original table
Retrieve the data from the database and perform the necessary merge logic
Compared the original table rows to the rows retrieved from the database and selected any row's whose RowVersion column changed
Raised a "RowModified" event for any rows that were changed in the database and catch these events in my business classes.

The following code is a demonstration of how I solved my problem on a simpler scale based on my previous demo project I mentioned in my problem.

Here is the XAML markup for the MainWindow in my WPF sample/demo project:

<Window x:Class="MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:TestingRowChangeAndMerge"
    Title="MainWindow" Height="350" Width="525">
<Window.Resources>
    <local:TableManger x:Key="TableManagerResource" />
</Window.Resources>
<Grid DataContext="{StaticResource TableManagerResource}">
    <Grid.RowDefinitions>
        <RowDefinition Height="*"/>
        <RowDefinition Height="Auto" />
    </Grid.RowDefinitions>
    <DataGrid ItemsSource="{Binding Table1.DefaultView}" AutoGenerateColumns="True" >

    </DataGrid>
    <StackPanel Grid.Row="1">
        <TextBlock Text="{Binding ChangesDetected}" />
    <Button x:Name="MergeTables" Content="Merge" Click="MergeTables_Click"/>
    </StackPanel>
</Grid>
</Window>

And here is the code for the Button Click event and the class that is used to demonstrate the merging of data.

MainWindow Code for Button Click event:

Class MainWindow

Private Sub MergeTables_Click(sender As System.Object, e As System.Windows.RoutedEventArgs)
    Dim tbManager As TableManger = FindResource("TableManagerResource")
    tbManager.MergeTables()
End Sub

End Class

TableManger Class:

Class TableManger
Implements ComponentModel.INotifyPropertyChanged

Public Event RowModified(ByVal id As Guid)
Private _table1 As System.Data.DataTable
Private _changesDetected As Integer = 0

Public ReadOnly Property Table1
    Get
        Return _table1
    End Get
End Property
Public ReadOnly Property ChangesDetected As Integer
    Get
        Return _changesDetected
    End Get
End Property

Public Sub New()
    _table1 = CreateTableWithData()
    _table1.AcceptChanges()

    AddHandler Me.RowModified, AddressOf RowModifiedHandler
End Sub

Public Sub MergeTables()
    _changesDetected = 0

    Dim tablePopulatedFromDB = SimulateGetDataFromDatabase()

    'The following is used test that changes are preserved during merging'
    'If _table1.Rows.Count > 0 Then'
    '    ' _table1.Rows(0)(1) = "TB1 Change"'
    '    _table1.Rows(1)(1) = "Change made by user"'
    'End If'

    Dim originalTableData = _table1.Copy
    Dim perserveChanges As Boolean = True
    Dim msAction As System.Data.MissingSchemaAction = System.Data.MissingSchemaAction.Ignore


    Dim changes As System.Data.DataTable = _table1.GetChanges()
    If changes IsNot Nothing Then
        changes.Merge(tablePopulatedFromDB, perserveChanges, msAction)
        _table1.Merge(changes, False, msAction)
    Else
        _table1.Merge(tablePopulatedFromDB, False, msAction)
    End If

    Dim changedRows = From tb1Row In _table1.Rows
                      Join origTBRow In originalTableData.Rows
                      On origTBRow("ID") Equals tb1Row("ID")
                      Where origTBRow("RowVersion") <> tb1Row("RowVersion")
                      Select tb1Row
    For Each changedRow In changedRows
        RaiseEvent RowModified(changedRow("ID"))
    Next

    RaiseEvent PropertyChanged(Me, New ComponentModel.PropertyChangedEventArgs("Table1"))
    RaiseEvent PropertyChanged(Me, New ComponentModel.PropertyChangedEventArgs("ChangesDetected"))

    MessageBox.Show(String.Format("Changes Detected: {0}", _changesDetected), "Testing")
End Sub

Private Sub RowModifiedHandler(ByVal id As Guid)
    _changesDetected += 1
End Sub

Private Function SimulateGetDataFromDatabase() As System.Data.DataTable
    Dim dbtable = _table1.Copy
    If dbtable.Rows.Count > 0 Then
        dbtable.Rows(0)(1) = String.Format("Change in Database...Old RowVersion: {0}", dbtable.Rows(0)("RowVersion")) 'simulating a change in data retrieved from the database for the first row

        Dim newRVersion As Integer 'Whenever a row is updated the row version is incremented in the database
        If dbtable.Rows.Count > dbtable.Rows(0)("RowVersion") Then
            newRVersion = dbtable.Rows.Count + 1
        Else
            newRVersion = dbtable.Rows(0)("RowVersion") + 1
        End If
        dbtable.Rows(0)(2) = newRVersion
    End If
    dbtable.AcceptChanges()

    Return dbtable
End Function

Private Function CreateTableWithData() As System.Data.DataTable
    Dim newTable As New System.Data.DataTable
    Dim columnID As New System.Data.DataColumn("ID", GetType(Guid))
    Dim columnA As New System.Data.DataColumn("ColumnA", GetType(String))
    Dim columnB As New System.Data.DataColumn("RowVersion", GetType(Integer))
    newTable.Columns.AddRange({columnID, columnA, columnB})
    newTable.PrimaryKey = {newTable.Columns(0)}
    For i = 0 To 5
        Dim dr = newTable.NewRow
        dr("ID") = Guid.NewGuid
        dr("ColumnA") = String.Format("Column A Row {0}", i.ToString)
        dr("RowVersion") = i
        newTable.Rows.Add(dr)
    Next
    Return newTable
End Function

Public Event PropertyChanged(sender As Object, e As System.ComponentModel.PropertyChangedEventArgs) Implements System.ComponentModel.INotifyPropertyChanged.PropertyChanged
End Class

Thank you @Bjørn-Roger Kringsjå for helping me figure out how to properly merge data tables in this thread: Merge two identical DataTables results in DataRowState.Modified

I really hope this helps others to understand this topic.