Datatable - Sum Each Cell In a Row

Question

There are lots of examples of how to get the sum of each cell in a column. I have not been able to find an example of how to sum each cell in a row and add that total into the new column called "Total" for example.

C# DataTable has the DataTable1.Compute("SUM(["Column Name"])", "")

Example of What I would like to do below. However I would also like to be able to exclude specific columns as they may not contain numbers.

Edit The table is dynamic and the number of columns may change.

Answer 1

You can use this loop:

table.Columns.Add("Total", typeof(decimal));
foreach (DataRow row in table.Rows)
{
    decimal rowSum = 0;
    foreach (DataColumn col in table.Columns)
    {
        if(!row.IsNull(col))
        {
            string stringValue = row[col].ToString();
            decimal d;
            if(decimal.TryParse(stringValue, out d))
                rowSum += d;
        }
    }
    row.SetField("Total", rowSum);
}

This should work with any column type.

Answer 2

DataTable has capability to create calculated columns. In your case you can create "Total" column as

DataTable1.Columns.Add("Total", typeof(Double));
DataTable1.Columns["Total"].Expression = "C1+C2+C3";

Answer 3

Example code for Yuriy's answer:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Data;

namespace DynamicColumns
{
    class MainClass
    {
        public static void Main (string[] args)
        {
            Console.WriteLine ("Total all quantity columns");

            var dt = new DataTable ();
            dt.Columns.Add ("ProductName", typeof(string));
            dt.Columns.Add ("Qty1", typeof(int));
            dt.Columns.Add ("Qty2", typeof(int));
            dt.Columns.Add ("Qty3", typeof(int));

            {
                var dr = dt.NewRow ();
                dr ["ProductName"] = "Keyboard";
                dr ["Qty1"] = 2;
                dr ["Qty2"] = 5;
                dr ["Qty3"] = 6;
                dt.Rows.Add (dr);
            }

            {
                var dr = dt.NewRow ();
                dr ["ProductName"] = "Mouse";
                dr ["Qty1"] = 5;
                dr ["Qty2"] = 1;
                dr ["Qty3"] = 2;
                dt.Rows.Add (dr);
            }




            string expression = 

                string.Join (" + ", 
                    dt.Columns.OfType<DataColumn>()
                        .Where(x => x.DataType == typeof(int))
                        .Select(x => x.ColumnName)
                         .ToArray() );

            dt.Columns.Add("Total", typeof(int)).Expression = expression;


            Console.WriteLine ("Expression: {0}",expression);

            Console.WriteLine ("\nProduct and totals");
            foreach (var r in dt.Rows.OfType<DataRow>()) {
                Console.WriteLine ("{0} {1}", r["ProductName"], r["Total"]);
            }


        }
    }
}

Output:

Expression: Qty1 + Qty2 + Qty3

Product and totals
Keyboard 13
Mouse 8

I would hazard a guess this (.Expression) is the most performant solution compared to lambda-ing our way to each row to each column, and even compared to looping each row and each column