VB.NET LINQ按多列分組

Question

我有下面的LINQ代碼，它有語法錯誤，我不知道如何解決它

         Dim query =
        From row In mainDatatable.AsEnumerable

    'the syntax Error is in the following line
      Group row By new  { row.Field(Of Double)("cprice") , row.Field(Of Integer)("ccategory")} 
Into ProductGroups
    '**************************

                Dim grpNumber = 1
                For Each grp In query
                    For Each row In grp.ProductGroups
                        row.SetField("gnum", grpNumber)
                    Next
                    grpNumber += 1
                Next


            End Sub

那我在做什么錯？

這是表格的樣子，我想按列cprice和ccategory分組

+---------------+---------------+-----------+------+
| Product Name  | cprice        | ccategory | gnum |
+---------------+---------------+-----------+------+
| Skirt Red     |            99 |         1 |      |
| Jeans Blue    |            49 |         2 |      |
| Jeans Black   |            49 |         2 |      |
| Skirt Blue    |            99 |         1 |      |
| T-shirt White |            20 |         2 |      |
| T-shirt Green |            20 |         2 |      |
| Jeans Grey    |            49 |         2 |      |
+---------------+---------------+-----------+------+

Answer 1

嘗試這個：

new with { Key.Price = row.Field(Of Double)("cprice") ,
           Key.Category = row.Field(Of Integer)("ccategory")

使用Key修飾符，這將創建一個匿名類型，該匿名類型基於其成員的相等性實現相等性 。