Adding a Calculated Column to a DataTable

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 :