DataTable foreach loop

DataTable can be used with foreach. It is possible (and often helpful) to loop through all the elements in the DataTable.

Looping notes

The DataTable class allows the use of the foreach-loop and its enumerator. But iterating over the items in a DataRow can be confusing.

An example

We use 2 public instance properties. These are Rows, which returns a typed collection of rows, and ItemArray, which returns a collection of cell values boxed in objects.

using System;
using System.Data;

class Program
{
    static void Main()
    {
        DataTable table = GetTable();
        foreach (DataRow row in table.Rows)
        {
            foreach (var item in row.ItemArray)
            {
                Console.WriteLine(item);
            }
        }
    }

    static DataTable GetTable()
    {
        DataTable table = new DataTable();
        table.Columns.Add("Size", typeof(int));
        table.Columns.Add("Category", typeof(string));
        table.Columns.Add("Name", typeof(string));
        table.Columns.Add("Date", typeof(DateTime));
        // Use 1 row for simplicity.
        table.Rows.Add(15, "dog", "Spot", DateTime.Now);
        return table;
    }
}
Item: 15
Item: dog
Item: Spot
Item: 11/3/2020 5:33:27 AM

Field foreach

You can also use the generic Field method that receives one type parameter. We can loop over Rows with foreach, and then use Field to get each cell.

using System;
using System.Data;

class Program
{
    static void Main()
    {
        DataTable table = GetTable();
        foreach (DataRow row in table.Rows)
        {
            var field1 = row.Field<int>(0);
            var field2 = row.Field<string>(1);
            var field3 = row.Field<string>(2);
            var field4 = row.Field<DateTime>(3);
            Console.WriteLine("{0} {1} {2} [{3}]", field1, field2, field3, field4);
        }
    }

    static DataTable GetTable()
    {
        DataTable table = new DataTable();
        table.Columns.Add("Size", typeof(int));
        table.Columns.Add("Category", typeof(string));
        table.Columns.Add("Name", typeof(string));
        table.Columns.Add("Date", typeof(DateTime));
        table.Rows.Add(15, "dog", "Spot", DateTime.Now);
        return table;
    }
}
15 dog Spot [11/3/2020 5:38:29 AM]

A summary

We examined foreach, Rows and ItemArray on the DataTable object. We can display and save all cell values in the DataTable at any time.