在VB.NET中,我们假设我有以下结构：
Public Structure Product
Public ItemNo As Int32
Public Description As String
Public Cost As Decimal
End Structure
…和产品的通用列表：
Dim ProductsList As New List(Of Product)
Dim product1 As New Product
With product1
.ItemNo = 100
.Description = "Standard Widget"
.Cost = 10D
End With
ProductsList.Add(product1)
Dim product2 As New Product
With product2
.ItemNo = 101
.Description = "Standard Cog"
.Cost = 10.95D
End With
ProductsList.Add(product2)
Dim product3 As New Product
With product3
.ItemNo = 101
.Description = "Industrial Strenght Sprocket"
.Cost = 99.95D
End With
ProductsList.Add(product3)
我如何定义一个LINQ查询以求列表中的所有Product.Cost值？换句话说,什么是LINQ
在VB.NET中查询返回值120.90,这反映了单个LINQ Query中所有三个Product Cost值的总和？
内置Sum方法已经这样做了.
在VB中,它看起来像这样：
ProductList.Sum(Function(item) item.Cost)
在C#中,它看起来像这样：
ProductsList.Sum( (item) => item.Cost);