Private m_UserTable as DataTable
Private m_UserBinder as BindingSource
...
'im constructor dann 
m_UserBinder = New BindingSource
DataGrid1.DataSource = m_UserBinder
...
Private Sub Get_All_User()
    Try
        m_UserTable = new DataTable("user")
        Dim DBDataAdapter As New MySqlDataAdapter("SELECT * FROM user", _
          DB_CONNECTIONSTRING)
        DBDataAdapter.Fill(m_UserTable)
        m_UserBinder.DataSource = m_UserTable
    Catch ex As MySqlException
        MsgBox(ex.Message)
    End Try
End Sub

Private Sub Add_User(ByVal tVorname As String, ByVal tNachname As String)
    Try
        Dim DBDataAdapter As New MySqlDataAdapter("SELECT * FROM user", _
          DB_CONNECTIONSTRING)
	MyNewRow = m_UserTable.NewRow
	MyNewRow("VC_VORNAME") = tVorname
	MyNewRow("VC_NACHNAME") = tNachname
	m_UserTable.Rows.Add(MyNewRow)
	Dim MyCommBuild As New MySqlCommandBuilder(DBDataAdapter)
	DBDataAdapter.Update(DBDataSet, "user")
    Catch ex As MySqlException
        MsgBox(ex.Message)
    End Try
End Sub