private void AddMaterialTypeCmd(object obj) { var materialType = obj as MaterialType; if (string.IsNullOrWhiteSpace(materialType.MaterialTypeName)) { return; } _repositoryManager.AddMaterialType(materialType); MaterialTypeToAdd = new MaterialType(); MaterialTypes = ProcessMaterialTypes(_repositoryManager.GetMaterialTypes()); MaterialToAdd.SelectedMaterialType = MaterialTypes.First(); OnPropertyChanged(nameof(MaterialToAdd)); }