public SelfInvoiceViewModel()
: base(NumberOfRowsInSelfInvoicesGrid)
{
_contoData = new ContoData();
ModifySelfInvoiceCommand = new RelayCommand(ModifySelfInvoiceCommand_Executed);
UpdateSelfInvoiceCloseCommand = new RelayCommand(UpdateSelfInvoiceCommandClose_Executed);
UpdateSelfInvoiceCommand = new RelayCommand(UpdateSelfInvoiceCommand_Executed);
RemoveSelfInvoiceCommand = new RelayCommand(RemoveSelfInvoiceCommand_Executed);
InvoiceDate = DateTime.Now;
InvoiceYear = DateTime.Now.Year;
VatExempt = true;
Materials = new List <Material>(_contoData.MaterialsGet());
ExistingMaterials = new List <Material>(Materials);
Measures = new List <Measures>(_contoData.MeasuresGet());
ExistingMeasures = new List <Measures>(_contoData.MeasuresGet());
Initialize(OnPropertyChanged, _contoData.SelfInvoicesMasterGet);
UpdatePanelVisibility = Visibility.Collapsed;
}