How do I most efficiently remove entries from a DataTable?

Question

I'm developing on a more or less legacy C# application and stumbled upon a code that I wrote some time ago. But somehow I get the feeling, that this is not really a good approach to this.

How would I make this code better?

        public static void RemoveEntries(DataTable source, ref DataTable destination, int indexSource, int indexDestination)
    {
        var arVals = new int[source.Rows.Count];
        var i = 0;
        foreach (DataRow sourceRow in source.Rows)
        {
            if (sourceRow.RowState != DataRowState.Deleted)
                arVals.SetValue(sourceRow[indexSource], i);
            i += 1;
        }

        foreach (
            var destinationRow in 
            from DataRow row3 
                in destination.Rows 
            where arVals.Contains((int) row3[indexDestination]) 
            where row3.RowState != DataRowState.Deleted 
            select row3
        )
            destinationRow.Delete();
    }

Thanks in advance, bb

Instead of using arVals, can't you just delete the rows in the first loop? Is there some sort of Primary Key field that would uniquely identify a row that exists in both tables? — wgraham
– wgraham, Commented May 23, 2013 at 13:03
"Better code" meaning less code that is more understandable. I'm not really sure why I even need 2 DataTables.. — bberger
– bberger, Commented May 24, 2013 at 7:18

Ken Kin · Accepted Answer · 2013-05-23 13:35:27Z

1

public static void RemoveEntries(
    DataTable source, int sourceIndex,
    DataTable destination, int destinationIndex) {
    var query=
        from DataRow rowDestination in destination.Rows
        where rowDestination.RowState!=DataRowState.Deleted
        from DataRow rowSource in source.Rows
        where rowSource.RowState!=DataRowState.Deleted
        where rowSource[sourceIndex]==rowDestination[destinationIndex]
        select rowDestination;

    foreach(var row in query.ToArray())
        row.Delete();
}

answered May 23, 2013 at 13:35

Ken Kin

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How do I most efficiently remove entries from a DataTable?

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