DataView

This C# class selectively filters and sorts DataTable rows. Part of System.Data, DataView is ideal for sorting data. We use the data in a DataTable by sorting it with DataView.

It is possible to filter a DataView, which allows you to exclude rows. Certain rows matching a condition can be omitted. The 2 properties we use here are RowFilter, and RowStateFilter.

Sort example

We use DataView to sort a column on a DataTable. The GetTable method returns a table with 2 columns. Before we can use DataView, we must have a complete table.

using System;
using System.Data;

class Program
{
    static void Main()
    {
        //
        // Specify the column to sort on.
        //
        DataTable table = GetTable();
        table.DefaultView.Sort = "Weight";

        //
        // Display all records in the view.
        //
        DataView view = table.DefaultView;
        Console.WriteLine("=== Sorted by weight ===");
        for (int i = 0; i < view.Count; i++)
        {
            Console.WriteLine("{0}, {1}", view[i][0], view[i][1]);
        }

        //
        // Now sort on the Name.
        //
        view.Sort = "Name";
        //
        // Display all records in the view.
        //
        Console.WriteLine("=== Sorted by name ===");
        for (int i = 0; i < view.Count; i++)
        {
            Console.WriteLine("{0}, {1}", view[i][0], view[i][1]);
        }
    }

    static DataTable GetTable()
    {
        //
        // Here we create a DataTable with 2 columns.
        //
        DataTable table = new DataTable();
        table.Columns.Add("Weight", typeof(int));
        table.Columns.Add("Name", typeof(string));

        //
        // Here we add unsorted data to the DataTable and return.
        //
        table.Rows.Add(57, "Spot");
        table.Rows.Add(130, "Rover");
        table.Rows.Add(92, "Fred");
        table.Rows.Add(25, "Alice");
        table.Rows.Add(7, "Hunter");
        return table;
    }
}
=== Sorted by weight ===
7, Hunter
25, Alice
57, Spot
92, Fred
130, Rover
=== Sorted by name ===
25, Alice
92, Fred
7, Hunter
130, Rover
57, Spot

Review, types

DataTable stores the physical data—the DataView is only a view of that data. You cannot easily sort a DataTable without a DataView reference.

Summary

We saw an example of using DataView to sort rows in a DataTable. It allows you to sort your data before using it in your program, and before putting it into a database.