private void AddVendorCommand(object model) { var vendor = model as Vendor; if (string.IsNullOrWhiteSpace(vendor.VendorName) || string.IsNullOrWhiteSpace(vendor.Address)) { return; } vendor.CreatedDate = DateTime.Now; _repositoryManager.AddVendor(vendor); var list = _repositoryManager.GetVendorBySiteId(SiteId); Vendors = new ObservableCollection <Vendor>(list); VendorToAdd = new Vendor(); VendorList = ProcessVendors(list); SelectedVendor = VendorList.First(); OnPropertyChanged(nameof(SelectedVendor)); }