Adding a Calculated Column to a DataTable

An expression column contains a value that is calculated from other column values in the same row, or from an aggregate of rows in the table or in a related table.

Adding a Calculated Column to a DataTable

An expression column contains a value that is calculated from other column values in the same row, or from an aggregate of rows in the table or in a related table. The DataType of the column must be compatible with the return value of the expression.

Following Example shows how to use a calculated column in a DataTable

 

using System;

using System.Data;

 

namespace CalculatedColumninaDataTable

{

    class Program

    {

        static void Main(string[] args)

        {

            DataTable Order = new DataTable();

          

            Order.Columns.Add("ProductName", typeof(string));

            Order.Columns.Add("Quantity", typeof(int));

            Order.Columns.Add("UnitPrice", typeof(decimal));

            Order.Columns.Add("UnitPriceDiscount", typeof(decimal));

           

// Add an expression column to the table.

            Order.Columns.Add("TotalPrice", typeof(decimal), "(UnitPrice -UnitPriceDiscount) * Quantity");

 

            DataRow newOrder = Order.NewRow();

            Order.Rows.Add("Widget",7,1.84,0.14);

            Order.Rows.Add("Bobbin", 8, 4.2,0.33);

            Order.Rows.Add("Sniglet", 4, 6.39,0.13);

            Order.Rows.Add("Wire", 8, 5.58,0.21);

            Order.Rows.Add("Gear", 10, 0.17,0.1);

 

          

            Console.WriteLine("ProductName  Quantity  UnitPrice      TotalPrice \n");

            foreach (DataRow row in Order.Rows)

                Console.WriteLine("{0}\t \t {1}\t  {2}\t \t {3} \n",

                                    row["ProductName"], row["Quantity"],

                                    row["UnitPrice"], row["TotalPrice"]);

 

            Console.WriteLine("\nPress any key to continue.");

            Console.ReadKey();

 

        }

    }

}

 

Output :