the demo xaml was tested multiple times by different people on different machines. Can you help us to understand your feedback: Is the test xaml not working at your end or is the integration / adoption into your implementation not working?
the case dtNonDuplicates is matching to your scenario
this is to inspect with setting breakpoints, debugging and watching the locals in the locals panel
so taking the statement from demo
(From d In dtData
Group d By k=d(0).toString.Trim Into grp=Group
Where grp.Count =1
Select grp.First()).CopyToDatatable
and adopting to your variablenames and columnname or index like
(From d In YourDataTableVar
Group d By k=d(“C”).toString.Trim Into grp=Group
Where grp.Count =1
Select grp.First()).CopyToDatatable
should work
Using the component from @balupad14 also is first stop to explore if a scenario can be solved with this as the component is very powerfull
Give a try in your case with:
(From d In dtData
Group d By k=d(2).toString.Trim Into grp=Group
Where grp.Count >1
Select grp.toList).SelectMany(Function (x) x).CopyToDatatable