How to Compare two Generic List one contain int and another contain class object

Question

How to compare these two Generic list and get the matching data as per ID

List<int> _GetRecCust;
List<Tranobject> GetTransDeta;

I tried

var TransactionsToProcess = GetTransDeta.Where(x => _GetRecCust.Contains(Convert.ToInt32(x.ID)));

but not able to get a comman ID data.

Both having ID as a field.

Thanks in advance

Answer 1

The most efficient approach is using Enumerable.Join:

var common = from x in GetTransDeta
             join id in _GetRecCust
             on int.Parse(x.Id) equals id
             select id;
List<int> commonIDs = common.ToList();

By the way, why is Tranobject.Id a string at all?

Edit: Since you have commented that there are nulls, you could use IsNullOrWhiteSpace first:

var common = from x in GetTransDeta
             where !string.IsNullOrWhiteSpace(x.Id)
             join id in _GetRecCust
             on int.Parse(x.Id) equals id
             select id;  

Answer 2

Try this:

GetTransData.Where(gtd => _GetRecCust.Any(grc => grc == int.Parse(gtd.Id))).ToList();