New to Linq, so apologies if this is basic. This query is throwing up the error {"Cannot cast DBNull.Value to type 'System.Int64'. Please use a nullable type."} when I enumerate the results.
private void AddLevels(long rootid)
{
var results = from row in data.AsEnumerable()
where row.Field<long>("ParentID") == rootid
select row;
foreach (DataRow row in results)
{
//do stuff
}
}
The column ParentID does accept nulls - do I need to handle these separately?
EDIT2: Actual solution below that still uses Linq.
EDIT: I solved this by scrapping Linq and just using a DataTable.Select statement instead. If anyone's got input on the performance difference I'd be interested.
See Question&Answers more detail:
os 与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…