String.ToLowerInvariant Method
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
Returns a copy of this string converted to lowercase using the casing rules of the invariant culture.
Assembly: mscorlib (in mscorlib.dll)
The invariant culture represents a culture that is culture-insensitive. It is associated with the English language but not with a specific country or region.
If your application depends on the case of a string changing in a predictable way that is unaffected by the current culture, use the ToLowerInvariant method. The ToLowerInvariant method is equivalent to ToLower(CultureInfo.InvariantCulture). The method is recommended when a collection of strings must appear in a predictable order in a user interface control.
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This method does not modify the value of the current instance. Instead, it returns a new string in which all characters in the current instance are converted to lowercase. |
The following example defines a string array that contains a single word in a number of languages. The ToLowerInvariant method is used to populate the elements of a parallel array with the case-insensitive version of each word. The Array.Sort<TKey, TValue>(TKey[], TValue[], IComparer<TKey>) method is used to sort the case-sensitive array based on the order of elements in the lowercase array to ensure that elements appear in the same order regardless of language.
using System; public class Example { public static void Demo(System.Windows.Controls.TextBlock outputBlock) { string[] words = { "Tuesday", "Salı", "Вторник", "Mardi", "Τρίτη", "Martes", "יום שלישי", "الثلاثاء", "วันอังคาร" }; // Display array in unsorted order. foreach (string word in words) outputBlock.Text += word + "\n"; outputBlock.Text += "\n"; // Create parallel array of words by calling ToUpperInvariant. string[] upperWords = new string[words.Length]; for (int ctr = words.GetLowerBound(0); ctr <= words.GetUpperBound(0); ctr++) upperWords[ctr] = words[ctr].ToUpperInvariant(); // Sort the words array based on the order of upperWords. Array.Sort(upperWords, words, StringComparer.InvariantCulture); // Display the sorted array. foreach (string word in words) outputBlock.Text += word + "\n"; } } // The example displays the following output: // Tuesday // Salı // Вторник // Mardi // Τρίτη // Martes // יום שלישי // الثلاثاء // วันอังคาร // // Mardi // Martes // Salı // Tuesday // Τρίτη // Вторник // יום שלישי // الثلاثاء // วันอังคาร
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