Question

I’m looking for a way to return a name value pair list directly from a Linq to SQL query without having to loop through the results like I’m doing in the code below:

Public Shared Function GetUserTransactionCounts(fromDate As DateTime, toDate As DateTime) As List(Of KeyValuePair(Of String, Integer))
    Using dc As New ProntoDataContext()
        Dim users As IEnumerable(Of User) = From u In dc.Users Where u.CreatedTransactions.Any(Function(t) t.TSCreate >= fromDate And t.TSCreate <= toDate)

        Dim list As New List(Of KeyValuePair(Of String, Integer))
        For Each user As User In users
            Dim item As New KeyValuePair(Of String, Integer)(user.CommonName, user.CreatedTransactions.Count)
            list.Add(item)
        Next
        Return list
    End Using
End Function

Answer 1

Try converting to IEnumerable, and then using Select:

Dim users As IEnumerable(Of User) = From u In dc.Users Where u.CreatedTransactions.Any(Function(t) t.TSCreate >= fromDate And t.TSCreate <= toDate)
Dim list As List(Of KeyValuePair(Of String, Integer)) = users.AsEnumerable().Select(Function(x) New KeyValuePair(Of String, Integer)(x.CommonName, x.CreatedTransactions.Count)).ToList()

EDIT : If you would like to make an IEnumerable, remove the ToList:

Dim enumerable As IEnumerable(Of KeyValuePair(Of String, Integer)) = users.AsEnumerable().Select(Function(x) New KeyValuePair(Of String, Integer)(x.CommonName, x.CreatedTransactions.Count))

This will not run the query until the enumerable is enumerated for the first time.