Linq to DataTable not producing Distinct values - asp.net

Question

I have a datatable which has been dynamically generated from FoxPro tables using a UNION Select statement. e.g.
SELECT * FROM x UNION SELECT * FROM y UNION SELECT * FROM Z ORDER By v_alue1
This produces a datatable with about 100 rows, each containing many fields, one of which is c_olor. From this datatable, I would like to select the distinct colors and then output in a dropdown.
I have a public class Color which just has one property which I can then use as the DataTextField and DataValueField for the dropdownlist
Public Class Color
Private _c_olor As String
Public Property c_olor() As String
Get
Return _c_olor
End Get
Set(ByVal value As String)
_c_olor = value
End Set
End Property
End Class
My linq statment is
Dim colorDs = (From o In dt.Rows Select Color = New With {.c_olor = o("c_olor").ToString().Trim(Nothing).ToLower()}).Distinct().ToList()
However this never results in the distinct colors.
I have searched and searched for what I am looking for, and this seems to be one of the methods to produce a distinct set of results, but this and the others do not work.
My reasoning behind getting the colors this way, is that I need to get various other distinct values from the same UNION SELECT datasource, so would just do one DB call, cache the results, and then just used this cached datasource to retrieve all my distinct values.

Answer 1

I'm not a VB expert but it seems like you're creating your colors first and then trying to find the distinct colors
In this case, you need to implement Equals on your color class
Dim colorDs = (From o In dt.Rows Select Color = New With {.c_olor = o("c_olor").ToString().Trim(Nothing).ToLower()}).Distinct().ToList()
Alternatively, you could find disctinct values first and then create color instances
Dim colorDs = (From o In dt.Rows Select o("c_olor").ToString().Trim(Nothing).ToLower()).Distinct().ToList()
Should produce the list of unique string colors