Best way to add a new column to a data table based on an existing column

Question

I have a data-table with data. I need to add another column to the datatable having the same value of another column but with less precision.

Ie the original column would be having value 12.123 but the new column will have value 12.12

What is the best way to do this?

Answer 1

Make a Computed Column so that your data integrity never violated

You can see this article to find out How

Answer 2

Something like this

            yourDataTable.Columns.Add("newCol", typeof(double));

            foreach (System.Data.DataRow row in yourDataTable.Rows)
            {
                row["newCol"] = Math.Round(Convert.ToDouble(row["oldCol"]), 2);                    
            }

Answer 3

Some grid implementations, like DevExpress XtraGrid, allow you to have unbound columns and easily provide values for them. The same thing would involve some hacking with a basic DataGridView, so I have an other suggestion. Add a new read-only property to your class: decimal value1 { get; set; } decimal value2 { get { return Math.Round(value1, 2); } } This way you don't even have to bother with the column display format.