I just posted this in another thread:

DataSet1.TableA.Select<DataSet1.TableARow, bool>(x => { DataSet2.TableA.ImportRow(x); return true; }).Count();

It shows up OK in the sent message but in the 'Preview' it looks like this:

DataSet1.TableA.Select<>(x => { DataSet2.TableA.ImportRow(x); return true; }).Count();

Bit disconcerting.....