VB.NET LINQ查询:获取特定结构成员的所有值之和

在VB.NET中,假设我具有以下结构:

Public Structure Product
    Public ItemNo As Int32
    Public Description As String
    Public Cost As Decimal
End Structure

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)

如何定义LINQ查询来汇总列表中的所有Product.Cost值?换句话说,什么是LINQ 在VB.NET中查询以返回值120.90,该值反映了单个LINQ查询中所有三个产品成本值的总和?