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From a VB multi-column DataTable select a single column of Sorted Distinct values copied to another DataTable RRS feed

  • Question

  • I am recently starting out in my use of LINQ in VB.Net and clearly I am in need of help and guidance.

    I have created a multi-column DataTable (TempSrvcCallTable) from which I am trying to extract a single-column(where Col is a string holding the name of the field) Sorted list  of Distinct values which I want to return in another DataTable.

    The nearest I have come is:

            Dim FilterLINQ = From R In TempSrvcCallTable.AsEnumerable()
                             Select R.Field(Of String)(Col).Distinct.OrderBy(Function(x) x)
            dt = FilterLINQ.CopyToDataTable
    

    Unfortunately the FilterLINQ.CopyToDataTable statement generates the error message " 'CopyToDataTable' is not a member of 'EnumerableRowCollection(Of IOrderedEnumerable(of Char))' " - and I don't know what this means or how to fix it.

    As ever, any help or assistance will be very gratefully received.

    Paul J

    Wednesday, September 9, 2015 2:09 PM

Answers

  • Many, many thanks Bonnie - a quick C# to VB adjustment and it works!

    dt = TempSrvcCallTable.DefaultView.ToTable(True, Col)

    Paul J

    Thursday, September 10, 2015 7:18 AM

All replies

  • Hi Paul,

    I'm not sure if the VB syntax is totally correct or not (I use C#), but this should work ... just tweak it for VB if you need to. For this particular scenario, you don't have to use LINQ.

    dt = TempSrvcCallTable.DefaultView.ToTable(true, New string[] { col })

    ~~Bonnie DeWitt [C# MVP]

    http://geek-goddess-bonnie.blogspot.com

    • Proposed as answer by BonnieBMVP Thursday, September 10, 2015 1:43 PM
    Wednesday, September 9, 2015 8:33 PM
  • Many, many thanks Bonnie - a quick C# to VB adjustment and it works!

    dt = TempSrvcCallTable.DefaultView.ToTable(True, Col)

    Paul J

    Thursday, September 10, 2015 7:18 AM
  • You're welcome, Paul. Glad I could help.

    In my reply, I used a different syntax for adding the column names to show what you would use if you needed more than one column: New string[] { col }  ... however, simply listing the column names is really all you had to use. Ignore my archaic syntax (not sure why I had it that way in my little test app, either way is correct).  So, for multiple columns it could be: ToTable(True,Col1, Col2, Col3). The True "distinct" in that case would mean distinct for all columns, but I know you just wanted one column.


    ~~Bonnie DeWitt [C# MVP]

    http://geek-goddess-bonnie.blogspot.com

    Thursday, September 10, 2015 2:01 PM