Question

我有一个看起来像这样的LINQ表达式

    Dim DataRowDueTo = From row In DataTableDueTo.AsEnumerable
                       Where row.Field(Of UInt32)("Transaction") = 1 And {"A", "B", "C"}.Contains(row.Field(Of String)("Module"))
                       Group By x = New With {Key .CustID = row.Field(Of UInt32)("CustID"), Key .Module = row.Field(Of String)("Module")} Into g = Group
                       Select New With {
                       .CustID = x.CustID,
                       .Module = x.Module,
                       .Sum= g.Sum(Function(r) r.Field(Of Decimal)("Amount"))
                       }

    ''DataTableDueToFinal is a datatable i have precreated with columns (CustID,Module and Sum)
    For Each grp In DataRowDueTo
        DataTableDueToFinal.Rows.Add(grp.CustID, grp.Module, grp.Sum)
    Next

基本上，我有一组数据（来自DataTable），其中GROUP BY 2列（CustID和Module）使用Where由{{1} }和TransactionSource。

产生的结果看起来像这样

Module

我的问题是，我试图使用不同的方法来重现相同的结果，但是我无法获得预期的结果。

+--------+--------+-----+
| CustID | Module | Sum |
+--------+--------+-----+
| 1      | A      | 50  |
+--------+--------+-----+
| 1      | B      | 45  |
+--------+--------+-----+
| 2      | A      | 23  |
+--------+--------+-----+
| 3      | A      | 234 |
+--------+--------+-----+
| 3      | B      | 76  |
+--------+--------+-----+

谁能指出我哪里出了问题？谢谢您的时间和考虑。

Answer 1

看起来像这样：

Dim DataRowDueTo = DataTableDueTo.AsEnumerable().Where(Function(w) w.Field(Of UInt32)("Transaction") = 1 And {"A", "B", "C"}.Contains(w.Field(Of String)("Module"))) _
                                                      .GroupBy(Function(row) New With {KEY .CustID = row.Field(Of UInt32)("CustID"),Key .Module = row.Field(Of String)("Module")})
      ''DataTableDueToFinal is a datatable i have precreated with columns (CustID,Module and Sum)
For Each grp In DataRowDueTo
    DataTableDueToFinal.Rows.Add(grp.Key.CustID, grp.Key.Module, grp.Sum(Function(row) row.Field(Of Decimal)("Amount")))
Next

Vb.net LINQ语法使用方法语法按多列分组

1 个答案: