Linq: Why won't Group By work when Querying DataSets?
- by jrcs3
While playing with Linq Group By statements using both DataSet and Linq-to-Sql DataContext, I get different results with the following VB.NET 10 code:
#If IS_DS = True Then
Dim myData = VbDataUtil.getOrdersDS
#Else
Dim myData = VbDataUtil.GetNwDataContext
#End If
Dim MyList = From o In myData.Orders
Join od In myData.Order_Details On o.OrderID Equals od.OrderID
Join e In myData.Employees On o.EmployeeID Equals e.EmployeeID
Group By FullOrder = New With
{
.OrderId = od.OrderID,
.EmployeeName = (e.FirstName & " " & e.LastName),
.ShipCountry = o.ShipCountry,
.OrderDate = o.OrderDate
} _
Into Amount = Sum(od.Quantity * od.UnitPrice)
Where FullOrder.ShipCountry = "Venezuela"
Order By FullOrder.OrderId
Select FullOrder.OrderId,
FullOrder.OrderDate,
FullOrder.EmployeeName,
Amount
For Each x In MyList
Console.WriteLine(
String.Format(
"{0}; {1:d}; {2}: {3:c}",
x.OrderId,
x.OrderDate,
x.EmployeeName,
x.Amount))
Next
With Linq2SQL, the grouping works properly, however, the DataSet code doesn't group properly.
Here are the functions that I call to create the DataSet and Linq-to-Sql DataContext
Public Shared Function getOrdersDS() As NorthwindDS
Dim ds As New NorthwindDS
Dim ota As New OrdersTableAdapter
ota.Fill(ds.Orders)
Dim otda As New Order_DetailsTableAdapter
otda.Fill(ds.Order_Details)
Dim eda As New EmployeesTableAdapter
eda.Fill(ds.Employees)
Return ds
End Function
Public Shared Function GetNwDataContext() As NorthwindL2SDataContext
Dim s As New My.MySettings
Return New NorthwindL2SDataContext(s.NorthwindConnectionString)
End Function
What am I missing? If it should work, how do I make it work, if it can't work, why not (what interface isn't implemented, etc)?
