我假設你有另一個ViewModel與ProductCategoryViewModel對象的集合?如果是這樣,我認爲可以有另一個只有活躍的產品類別的集合。我不確定您需要單獨的服務方法,因爲您可以根據Active值過濾您的產品類別集合。
如果這個視圖模型將被稱爲ProductCategoriesViewModel,它可能是這樣的:
using System.Collections.Generic;
using System.Linq;
using GalaSoft.MvvmLight;
namespace OCEAN.EPP.ViewModel
{
public class ProductCategoriesViewModel : ViewModelBase
{
public ProductCategoriesViewModel()
{
if (IsInDesignMode)
{
ProductCategories = new List<ProductCategoryViewModel>
{
new ProductCategoryViewModel { Active = false },
new ProductCategoryViewModel { Active = false },
new ProductCategoryViewModel { Active = true },
new ProductCategoryViewModel { Active = true },
};
}
else
{
// Code runs "for real": Connect to service, etc...
}
}
public const string ProductCategoriesPropertyName = "ProductCategories";
private List<ProductCategoryViewModel> _productCategories = new List<ProductCategoryViewModel>();
public List<ProductCategoryViewModel> ProductCategories
{
get { return _productCategories; }
set
{
if (_productCategories == value)
return;
_productCategories = value;
FilterActiveProductCategories();
RaisePropertyChanged(ProductCategoriesPropertyName);
}
}
public const string ActiveProductCategoriesPropertyName = "ActiveProductCategories";
private List<ProductCategoryViewModel> _activeProductCategories = new List<ProductCategoryViewModel>();
public List<ProductCategoryViewModel> ActiveProductCategories
{
get { return _activeProductCategories; }
set
{
if (_activeProductCategories == value)
return;
_activeProductCategories = value;
RaisePropertyChanged(ActiveProductCategoriesPropertyName);
}
}
private void FilterActiveProductCategories()
{
ActiveProductCategories = ProductCategories.Where(pc => pc.Active).ToList();
}
}
}