將保存列表<CartItem>添加到ASP.NET中的會話中

Question

CartItems保存在SQL數據庫中。

我想把所有的CartItems放在List中並傳遞給Instance.Items。

實例變量正在保存到會話中。

代碼如下。

public class ShoppingCart 
{ 
    public List<CartItem> Items { get; private set; } 
    public static SqlConnection conn = new SqlConnection(connStr.connString); 
    public static readonly ShoppingCart Instance; 

    static ShoppingCart() 
    { 
     if (HttpContext.Current.Session["ASPNETShoppingCart"] == null) 
     { 
       Instance = new ShoppingCart(); 
       Instance.Items = new List<CartItem>(); 
       HttpContext.Current.Session["ASPNETShoppingCart"] = Instance; 
     } 
     else 
     { 
      Instance = (ShoppingCart)HttpContext.Current.Session["ASPNETShoppingCart"]; 
     } 
    } 

返回List的代碼。我想將從此函數返回的List保存到Instance.Items。這樣它可以保存到會話中。

public static List<CartItem> loadCart(String CustomerId) 
    { 
     String sql = "Select * from Cart where CustomerId='" + CustomerId + "'"; 
     SqlCommand cmd = new SqlCommand(sql, conn); 
     List<CartItem> lstCart = new List<CartItem>(); 
     try 
     { 
      conn.Open(); 
      SqlDataReader reader = cmd.ExecuteReader(); 
      while (reader.Read()) 
      { 
       CartItem itm = new CartItem(Convert.ToInt32(reader["ProductId"].ToString())); 
       itm.Quantity = Convert.ToInt32(reader["Quantity"].ToString()); 
       lstCart.Add(itm); 
      } 

     } 
     catch (Exception ex) 
     { } 
     finally 
     { 
      conn.Close(); 
     } 

     return lstCart; 
    } 

Answer 1

如果您將整個對象提交給會話，則應將項存儲在與對象的會話中。

爲什麼不這樣做，而不是？：

public class ShoppingCart 
{ 
    public List<CartItem> Items { get; private set; } 
    public static SqlConnection conn = new SqlConnection(connStr.connString); 
    public static readonly ShoppingCart Instance; 

    static ShoppingCart RetrieveShoppingCart() 
    { 
     if (HttpContext.Current.Session["ASPNETShoppingCart"] == null) 
     { 
       Instance = new ShoppingCart(); 
       Instance.Items = new List<CartItem>(); 
       HttpContext.Current.Session["ASPNETShoppingCart"] = Instance; 
     } 
     else 
     { 
      Instance = (ShoppingCart)HttpContext.Current.Session["ASPNETShoppingCart"]; 
     } 

     return Instance; 
    } 
}