Question

I want to delete DataRows from a DataTable. The rows to be deleted are in a datarow list "wantDelete".
Please correct my code because of an exception:

foreach (DataRow dr in myTable.Rows)
{
     if (wantDelete.Contains(dr))
     myTable.Rows.Remove(dr);
}

The exception is:

Thank you very much.

Answer 1

You cannot modify a collection during enumeration because foreach uses an enumerator, and enumerators can’t change the underlying collection.

So you either should use a for-loop or use another collection(deleteItems) that you have pre filtered.

I see in your code that you’ve already prefiltered it(i assume wantDelete is a List<DataRow>):

foreach (DataRow dr in wantDelete)
{
     myTable.Rows.Remove(dr);
}

Side note: you know that removing rows from a DataTable does not delete them in your dbms if you’re using a DataAdapter? Therefor you would need to use DataRow.Delete().