I
think I found what you need... Here:
http://msdn.microsoft.com/en-us/library/ms994325.aspxQUOTE
Culture, which is indicated by the Thread.CurrentCulture property, corresponds by default to the selection in Regional Options in the control panel. This affects how numbers, dates, and times are formatted, and is also what determines which sorting and casing rules to use. This is the property we are concerned with here.
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The most commonly used routines that have this variation in behavior, depending on the culture, are String.Compare, String.ToUpper and String.ToLower. There are also some other important routines that call these, and which pass on the default behavior.
Whether or not you want these operations to vary depending on the culture depends a lot on what you are doing. If you are displaying a sorted list of localized strings in a list box, then you probably do want a culturally-aware comparison. If you are comparing a string to see if it is a recognized XML tag, then you do not want any variation. Most routines that have culture-dependent behavior will give you the option of passing in the culture to use directly; passing in CultureInfo.InvariantCulture is the way to eliminate the variation.