{"id":2574,"date":"2023-07-03T13:58:44","date_gmt":"2023-07-03T06:58:44","guid":{"rendered":"https:\/\/csharptutorial.net\/?page_id=2574"},"modified":"2023-07-03T14:44:11","modified_gmt":"2023-07-03T07:44:11","slug":"csharp-string-toupper","status":"publish","type":"page","link":"https:\/\/www.csharptutorial.net\/csharp-string-methods\/csharp-string-toupper\/","title":{"rendered":"C# String ToUpper"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you will learn how to use the C# String ToUpper()<\/code> method to convert a string to uppercase.<\/p>\n\n\n\n

Introduction to the C# ToUpper() method<\/h2>\n\n\n\n

The String<\/a> ToUpper()<\/code> method returns a copy of the current string converted to uppercase. Here’s the syntax of the ToUpper()<\/code> method:<\/p>\n\n\n

public<\/span> string ToUpper();<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
The following example uses the ToUpper()<\/code> method to convert the message \"Hello, World!\"<\/code> to uppercase:<\/p>\n\n\n
using<\/span> static<\/span> System.Console;\n\nvar<\/span> message = \"Hello, World!\"<\/span>;\nvar<\/span> upper = message.ToUpper();\n\nWriteLine(upper);<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
HELLO, WORLD!<\/code><\/span>Code language:<\/span> plaintext<\/span> (<\/span>plaintext<\/span>)<\/span><\/small><\/pre>\n\n\n
By default, the ToUpper()<\/code> method takes the case rule of the current culture into the conversion. But if you want to convert a string to uppercase using a specific culture, you can use the following overload of the ToUpper()<\/code> method:<\/p>\n\n\n
public<\/span> string<\/span> ToLower<\/span> (\n   System.Globalization.CultureInfo? culture\n<\/span>)<\/span>;<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
In this syntax, the culture<\/code> is an instance of CultureInfo<\/code> that specifies a culture-specific casing rule.<\/p>\n\n\n\n
For example, the following program illustrates how to use different CultureInfo<\/code> objects can lead to different uppercase conversions based on specific language rules:<\/p>\n\n\n
using<\/span> System.Globalization;\nusing<\/span> static<\/span> System.Console;\nvar<\/span> s = \"istanbul \u0130zmir Ankara\"<\/span>;\n\n\/\/ Using the default (English) culture<\/span>\nvar<\/span> englishUppercase = s.ToUpper(CultureInfo.InvariantCulture);\nWriteLine(\"Default (English) uppercase: \"<\/span> + englishUppercase);\n\n\/\/ Using the Turkish culture<\/span>\nvar<\/span> turkishCulture = new<\/span> CultureInfo(\"tr-TR\"<\/span>);\nvar<\/span> turkishUppercase = s.ToUpper(turkishCulture);\nWriteLine(\"Turkish uppercase: \"<\/span> + turkishUppercase);<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
In this example, we have a string that contains Turkish characters, such as \"\u0130\"<\/code> (capital \u0130<\/code> with a dot) and \"\u0130\"<\/code> (small i<\/code> with a dot) which are specific to the Turkish alphabet.<\/p>\n\n\n\n
When we use the ToUpper()<\/code> to convert a string to uppercase using the default culture (English), the method uses the English rules for uppercase conversion, and we get \"ISTANBUL \u0130ZMIR ANKARA\"<\/code>.<\/p>\n\n\n\n
However, when we use the ToUpper()<\/code> method with the Turkish culture (\"tr-TR\"<\/code>), the method uses Turkish-specific uppercase rules for conversion. <\/p>\n\n\n\n
In Turkish, the uppercase equivalent of \"i\"<\/code> is \"\u0130\"<\/code> without a dot, and the uppercase equivalent of \"\u0130\"<\/code> is \"I\"<\/code> (capital I without a dot). As a result, the Turkish uppercase string becomes \"\u0130STANBUL \u0130ZM\u0130R ANKARA\"<\/code>.<\/p>\n\n\n\n
C# String ToUpperInvariant()<\/h2>\n\n\n\n
The String ToUpperInvariant()<\/code> returns an uppercase version of a string using the casing rules of the invariant culture.<\/p>\n\n\n\n
Here’s the syntax of the ToUpperInvariant()<\/code> method:<\/p>\n\n\n
public<\/span> string ToUpperInvariant();<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
The ToUpperInvariant()<\/code> method is equivalent to the ToUpper()<\/code> method with the CultureInfo.InvariantCulture<\/code> argument:<\/p>\n\n\n
ToUpper<\/span>(CultureInfo<\/span>.InvariantCulture<\/span>)<\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
One practical example of using the ToUpperInvariant()<\/code> method is when you need to perform a case-sensitive string comparison.<\/p>\n\n\n\n
Using ToUpperInvariant()<\/code> ensures consistent behavior and avoids potential issues with culture-specific rules.<\/p>\n\n\n\n
Summary<\/h2>\n\n\n\n
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  • Use the C# String ToUpper()<\/code> method to convert a string to uppercase.<\/li>\n<\/ul>\n
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