Returns a copy of this string converted to uppercase, using the casing rules of the specified culture.
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The uppercase equivalent of the current string.
The casing rules of the culture specified by the culture parameter determine the way the case of a string is changed.
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 uppercase.
If you pass the string.ToUpper(System.Globalization.CultureInfo) method a System.Globalization.CultureInfo object other than System.Globalization.CultureInfo.InvariantCulture, the casing operation will take culture-specific rules into account. If you need the lowercase or uppercase version of an operating system identifier, such as a file name, named pipe, or registry key, use the string.ToLowerInvariant or string.ToUpperInvariant method. This produces the same result in every culture and performs more efficiently.