TextInfo

This type is found in System.Globalization—it provides several C# methods. For example, it has methods for changing the case of strings.

Method intro

You can call the ToTitleCase method to uppercase the first letter in each word in a string. You can also call the ToUpper method to uppercase all letters in the string.

An example

In .NET we have a TextInfo class that encapsulates certain string-level methods. The TextInfo class provides a ToLower method, a ToTitleCase method, and a ToUpper method.

using System;
using System.Globalization;

class Program
{
    static void Main()
    {
        // Access TextInfo virtual property accessors.
        TextInfo textInfo1 = CultureInfo.InvariantCulture.TextInfo;
        TextInfo textInfo2 = CultureInfo.CurrentCulture.TextInfo;

        // Example strings.
        const string value1 = "Yellow Bird";
        const string value2 = "YELLOW BIRD 012345";
        const string value3 = "yellow bird";

        // Use the ToLower method on the TextInfo variables.
        string lower1 = textInfo1.ToLower(value1);
        string lower2 = textInfo1.ToLower(value2);
        string lower3 = textInfo2.ToLower(value3);

        // Write lowercased strings to the screen.
        Console.WriteLine(lower1);
        Console.WriteLine(lower2);
        Console.WriteLine(lower3);
    }
}
yellow bird
yellow bird 012345
yellow bird

Benchmark, TextInfo ToLower

The benchmark shows that you can improve performance by using a CultureInfo.CurrentCulture.TextInfo variable and calling the instance ToLower method on it.

using System;
using System.Diagnostics;
using System.Globalization;

class Program
{
    const int _max = 1000000;
    static void Main()
    {
        TextInfo textInfo = CultureInfo.CurrentCulture.TextInfo;
        var s1 = Stopwatch.StartNew();
        // Version 1: use TextInfo ToLower.
        for (int i = 0; i < _max; i++)
        {
            string lower = textInfo.ToLower("GRAYCAT");
        }
        s1.Stop();
        var s2 = Stopwatch.StartNew();
        // Version 2: use String method.
        for (int i = 0; i < _max; i++)
        {
            string lower = "GRAYCAT".ToLower();
        }
        s2.Stop();
        Console.WriteLine(((double)(s1.Elapsed.TotalMilliseconds * 1000000) / _max).ToString("0.00 ns"));
        Console.WriteLine(((double)(s2.Elapsed.TotalMilliseconds * 1000000) / _max).ToString("0.00 ns"));
    }
}
29.88 ns    TextInfo ToLower
40.72 ns    String ToLower

A review

You can use the TextInfo class to lowercase strings. TextInfo methods (such as ToUpper and ToTitleCase) provide excellent ways to transform string characters.