初始化ASP.NET MVC中的空白dbSet 3

Question

我在if語句中定義了一個變量，然後嘗試在該語句的上下文之外使用該變量。如何在if語句之外初始化空的dbSet以便viewModel可以看到/填充它？

這就是我試圖完成：

if (order.type.ToString() == "Rush") 
{ 
    var filteredOrders = db.Orders.Where(a => a.rushID == order.rushID).ToList(); 
} 
else if (order.type.ToString() == "Standard") 
{ 
    var filteredOrders = db.Orders.Where(a => a.standardID == order.standardID).ToList(); 
} 
else 
{ 
    return HttpNotFound(); 
} 

var viewModel = new OrderDetailsViewModel 
{ 
    PastOrders = filteredOrders, // filteredOrders doesn't exist here 
    Order = order; 
}; 

Answer 1

IEnumerable<Order> filteredOrders; // or IList<Order>, etc., as your prefer 

switch (order.type.ToString()) 
{ 
    case "Rush": 
     filteredOrders = db.Orders.Where(a => a.rushID == order.rushID).ToList(); 
    case "Standard": 
     filteredOrders = db.Orders.Where(a => a.standardID == order.standardID).ToList(); 
    default:: 
     return HttpNotFound(); 
} 

var viewModel = new OrderDetailsViewModel 
{ 
    PastOrders = filteredOrders, 
    Order = order; 
}; 

---

或更好：

Func<Order, bool> filter; 

switch (order.type.ToString()) 
{ 
    case "Rush": 
     filter = a => a.rushID == order.rushID; 
    case "Standard": 
     filter = a => a.standardID == order.standardID; 
    default:: 
     return HttpNotFound(); 
} 

var viewModel = new OrderDetailsViewModel 
{ 
    PastOrders = db.Orders.Where(filter).ToList(), 
    Order = order; 
};