Public Class frmDBEdit2
 
    Dim dt As New DataTable
    Dim bs As New BindingSource(dt, Nothing)
 
    Dim WithEvents btnAddNew As New Button _
                            With {.Text = "Neuer Datensatz", .Parent = Me, _
                            .Width = 200}
 
    Dim dgv As New DataGridView With _
                     {.Parent = Me, .Top = 40, .Width = 300, .DataSource = bs, _
                    .AllowUserToAddRows = False, .AllowUserToDeleteRows = False}
 
    Private Sub frmDBEdit2_Load(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles MyBase.Load
 
        Me.Size = New Size(400, 400)
 
        'Testdaten erstellen
        With dt
            .Columns.Add("ID", GetType(Integer))
            .Columns.Add("Kunde")
            .PrimaryKey = {dt.Columns("ID")}
            .Rows.Add(1, "Hans Meier")
            .Rows.Add(2, "Kurt Müller")
        End With
    End Sub
 
    Private Sub btnAddNew_Click(ByVal sender As Object, _
                        ByVal e As System.EventArgs) Handles btnAddNew.Click
 
        'Neuer Datensatz wird erstellt (incl. Primarschlüssel)
        bs.AddNew()
        CType(bs.Item(bs.Count - 1), DataRowView).Row("ID") = bs.Count
 
        Using frmAddNewDialog As New frmDBAddnewDialog
            With frmAddNewDialog
                .HeaderText = "Name des neuen Kunden"
                'Datenbindung im Dialog-Formular
                .NameBinding = New Binding("Text", bs, dt.Columns( _
                  "Kunde").ColumnName)
 
                If .ShowDialog() = DialogResult.Cancel Then
                    bs.RemoveCurrent() 'Datensatz verwerfen
                Else
                    bs.ResetCurrentItem() 'Control aktualisieren
                End If
            End With
        End Using
    End Sub
End Class

Public Class frmDBAddnewDialog
 
    Dim tboName As New TextBox With _
        {.Parent = Me, .Top = 10, .Left = 10, .Width = 200}
 
    Dim WithEvents btnOk As New Button With _
                {.Parent = Me, .Top = 40, .Left = 10, .Width = 100, _
                 .Text = "OK", .DialogResult = Windows.Forms.DialogResult.OK}
 
    Dim WithEvents btnCancel As New Button With _
                {.Parent = Me, .Top = 40, .Left = 110, .Width = 100, _
                 .Text = "Cancel", .DialogResult = _
                 Windows.Forms.DialogResult.Cancel}
 
    Public Property HeaderText() As String
        Set(ByVal value As String)
            Me.Text = value
        End Set
        Get
            Return Me.Text
        End Get
    End Property
 
    'Eigenschaft für die Datenbindung
    Public Property NameBinding As Binding
        Set(ByVal value As Binding)
            tboName.DataBindings.Clear()
            tboName.DataBindings.Add(value)
        End Set
        Get
            If tboName.DataBindings.Count < 1 Then Return Nothing
            Return tboName.DataBindings(0)
        End Get
    End Property
 
    Public Function ValidateInput() As Boolean
        'Hier Code zur Validierung der Eingabe einfügen
        Dim input_ok As Boolean
        input_ok = Not String.IsNullOrWhiteSpace(tboName.Text)
        Return input_ok
    End Function
 
    Private Sub frmDBAddnewDialog_FormClosing(ByVal sender As Object, _
        ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles _
        Me.FormClosing
 
        If DialogResult = Windows.Forms.DialogResult.OK Then
            'Bei Betätigung des OK-Biuttons -> Eingabe-Validierung vornehmen
            If Not ValidateInput() Then
                MsgBox("Eingabe unzulässig")
                e.Cancel = True
            End If
        End If
    End Sub
 
End Class