Help with "Except" operator

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I am using the "Except" operator in the following code. It returns the differences fine, but all I'm getting is the PK_PhoneTypeID (of course). I need to populate a Drop-Down List with "PhoneTypes". I cant figure out how to return this column with my "Except" query, or how to nest another query to return the "PhoneTypes" column.

This is basically what the tables look like:

Phones
PK_ID
FK_ContactID
FK_PhoneTypeID

PhoneTypes
PK_PhoneTypeID
PhoneTypes

Here is my "Except" code and ddl binding:

VB

Dim hiddenGUID As HiddenField = CType(Wizard1.FindControl("Wizardstep3$HiddenField1"), HiddenField)

        Dim dc As New DataClassesDataContext()

        Dim q = (From x In dc.PhoneTypes _
                Select x.PhoneTypeID).Except _
                    (From c In dc.Phones _
                    Where c.ContactID.ToString() = hiddenGUID.Value _
                    Select c.PhoneTypeID)


        'The two commented lines below is what I'm trying to do

        DropDownList2.DataSource = q
        'DropDownList2.DataTextField = "PhoneTypes"
        'DropDownList2.DataValueField = "PhoneTypeID"
        DropDownList2.DataBind()

Posted 14-Sep-11 8:30am

jfclark27

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jfclark27 · Answer 1 · 2011-09-15T13:11:00

Writing a sql statement to do this was easy, so I decided to use the statement directly in Linq to SQL

VB

Dim q As IEnumerable(Of PhoneType) = _
        dc.ExecuteQuery(Of PhoneType) _
                ("select pt.PhoneTypeID, pt.PhoneTypes " & _
                "from PhoneTypes as pt " & _
                "where Not exists " & _
                "(select PhoneTypeID " & _
                "from phones " & _
                "where PhoneTypeID = pt.PhoneTypeID and ContactID ='" + hiddenGUID.Value + "') " & _
                "order by pt.PhoneTypeID;")
        DropDownList2.DataSource = q
        DropDownList2.DataTextField = "PhoneTypes"
        DropDownList2.DataValueField = "PhoneTypeID"
        DropDownList2.DataBind()

jfclark27 · Answer 2 · 2011-09-20T06:04:00

I Kept playing around and found a pure Linq to SQL solution:

SQL

Dim q = From pt In dc.PhoneTypes _
 Where Not (Not (From phones In dc.Phones _
 Where phones.PhoneTypeID = pt.PhoneTypeID And phones.ContactID = ContactGUID _
 Select New With {phones.PhoneTypeID}).Single() Is Nothing) _
 Select pt.PhoneTypeID, pt.PhoneTypes

I hope this helps someone...

Help with "Except" operator

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