Question

I have a in-memory DataTable and I need to mark the duplicates ….. for example ..

From

To

I would probably do something like ..

    For each dtrow in dt.rows
    If dtrow("Country") Is one of Duplicates then
            dtrow("Country") += "*"
    end if
    Next

Sorry for asking so many questions … My head is burnt .. nothing came out .. and this project is needing to finish very soon ..

Answer 1

You could use LINQ-to-DataTable:

Dim dups = From row In dt.AsEnumerable()
           Let country = row.Field(Of String)("Country")
           Group row By country Into DupCountries = Group
           Where DupCountries.Count() > 1
           Select DupCountries
For Each dupCountryRows In dups
    For Each row In dupCountryRows
        row("Country") = row.Field(Of String)("Country") & "*"
    Next
Next

Or with C# syntax:

var dups = from row in dt.AsEnumerable()
           let id = row.Field<string>("Country")
           group row by country
           into DupCountries where DupCountries.Count() > 1
           select DupCountries;