创建一个通用的方法

Question

我试图为以下代码的一般方法：

foreach (var glitter in glitterpurchase.GlitterPurchaseDetails) 
{ 
    var glitterInventory = _db.GlitterInventoriesRepository.GetAll(m => m.GlitterId == glitter.GlitterId); 
    if (!glitterInventory.Any()) 
    { 
     var newInventory = new GlitterInventory 
     { 
      GlitterId = glitter.GlitterId, 
      Quantity = glitter.Quantity, 
      TotalAmount = (decimal)glitter.Quantity * glitter.UnitPrice, 
      UnitPrice = glitter.UnitPrice, 
      CreatedBy = User.Identity.Name, 
      CreatedDate = DateTime.Now, 
     }; 
     _db.GlitterInventoriesRepository.Insert(newInventory); 
    } 
    else      
    { 
     var updateInventory = glitterInventory.First(); 
     updateInventory.Quantity += glitter.Quantity; 
     updateInventory.TotalAmount += (decimal)glitter.Quantity * glitter.UnitPrice; 
     updateInventory.UnitPrice = (decimal)updateInventory.Quantity/updateInventory.TotalAmount; 
     updateInventory.UpdatedBy = User.Identity.Name; 
     updateInventory.UpdatedDate = DateTime.Now; 
     _db.GlitterInventoriesRepository.Update(updateInventory); 
    } 
} 

上面的代码只是简单的更新库存。我想制作一个通用方法，以便我可以调用该方法并更新不同项目（类）的库存。我不擅长与泛型和研究我写了下面的代码之后：

public virtual void UpdateInventory<PurchasedEntity, Inventory>(IEnumerable<PurchasedEntity> purchaseDetails, GenericRepository<Inventory> inventory, Expression<Func<Inventory, bool>> filterForInventory) 
      where PurchasedEntity : class 
      where Inventory : class 

{ 
    foreach (var item in purchaseDetails) 
    { 
     var glitterInventory = inventory.GetAll(filterForInventory); 
     if (!glitterInventory.Any()) 
     { 
      var newInventory = (Inventory)Activator.CreateInstance(typeof(Inventory), new object[] 
      { 
       GlitterId = item.GlitterId, 
       Quantity = item.Quantity, 
       TotalPrice = (decimal)item.Quantity * item.UnitPrice, 
       UnitPrice = item.UnitPrice, 
       CreatedBy = User.Identity.Name, 
       CreatedDate = DateTime.Now, 
      }); 

      inventory.Insert(newInventory); 
     } 
     else 
     { 
      var updateInventory = glitterInventory.First(); 
      updateInventory.Quantity += item.Quantity; 
      updateInventory.TotalAmount += (decimal)item.Quantity * item.UnitPrice; 
      updateInventory.UnitPrice = (decimal)updateInventory.Quantity/updateInventory.TotalAmount; 
      updateInventory.UpdatedBy = User.Identity.Name; 
      updateInventory.UpdatedDate = DateTime.Now; 
      inventory.Update(updateInventory); 
     } 
    } 
} 

的问题是，我收到以下错误：

'PurchasedEntity' does not contain a definition for 'GlitterId' and no extension method 'GlitterId' accepting a first argument of type 'PurchasedEntity' could be found (are you missing a using directive or an assembly reference?) 

如何删除这个错误，并得到该类的属性一般？

我甚至不知道我写的代码是否有用，如果你能改善它，那就太好了，那太棒了。谢谢。

Answer 1

我假设并非每个PurchasedEntity都有一个GlitterId（并且可能不应取决于您的域）。因此，确定适当的Id财产上PurchasedEntity（或更好，但其解压缩到一个接口）：

interface IPurchasedEntity{ 
    Guid Id {get;} 
} 

更新GlitterInventory实施IPurchasedEntity：

public class GlitterInventory : IPurchasedEntity{ 
    Guid IPurchasedEntity.Id { get{ return GlitterId; }} 
} 

然后你UpdateInventory方法应该读Id，而不是GlitterId ：

public virtual void UpdateInventory<PurchasedEntity, Inventory>(
    IEnumerable<PurchasedEntity> purchaseDetails, 
    GenericRepository<Inventory> inventory, 
    Expression<Func<Inventory, bool>> filterForInventory) 
     where PurchasedEntity : IPurchasedEntity, class 
     where Inventory : IPurchasedEntity, class, new() 
{ 
    foreach (var item in purchaseDetails) 
    { 
     var inventory = new Inventory(); 
     inventory.Id = item.Id; 
     // if you have more standard fields, define them in IPurchasedEntity 
    } 
} 

更新：尝试从PurcahsedEntity和Inventory推断出您的域名后，调用IPurchasedEntityIInventory代替并定义您的通用属性可能更有意义。