Remove columns from DataTable in C#

Question

I have a DataSet which I get a DataTable from that I am being passed back from a function call. It has 15-20 columns, however I only want 10 columns of the data.

Is there a way to remove those columns that I don't want, copy the DataTable to another that has only the columns defined that I want or is it just better to iterate the collection and just use the columns I need.

I need to write the values out to a fixed length data file.

Answer 1

Aside from limiting the columns selected to reduce bandwidth and memory:

       DataTable t;
       t.Columns.Remove("columnName");
       t.Columns.RemoveAt(columnIndex);

Answer 2

Where are you getting the Data Set from? Are you using that particular DataTable somewhere else? Often it is best to limit the columns at the source. If you are populating the DataSet from the results of a query, you might try limiting the data fetched.

Answer 3

I would just not write the columns you are not interested in to the flat file.

Answer 4

To remove all columns after the one you want, this little function should work. It will remove at index 10 (remember Columns are 0 based), until the Column count is 10 or less.

        DataTable dt;
        int desiredSize = 10;

        while (dt.Columns.Count > desiredSize)
        {
            dt.Columns.RemoveAt(desiredSize);
        }