Compares two specified string objects using the specified comparison options and culture-specific information to influence the comparison, and returns an integer that indicates the relationship of the two strings to each other in the sort order.
A 32-bit signed integer that indicates the lexical relationship between strA and strB, as shown in the following table
Less than zero
strA is less than strB.
strA equals strB.
Greater than zero
strA is greater than strB.
The comparison uses the culture parameter to obtain culture-specific information, such as casing rules and the alphabetical order of individual characters. For example, a particular culture could specify that certain combinations of characters be treated as a single character, that uppercase and lowercase characters be compared in a particular way, or that the sort order of a character depends on the characters that precede or follow it.
The string.Compare(string, string, System.Globalization.CultureInfo, System.Globalization.CompareOptions) method is designed primarily for use in sorting or alphabetizing operations. It should not be used when the primary purpose of the method call is to determine whether two strings are equivalent (that is, when the purpose of the method call is to test for a return value of zero). To determine whether two strings are equivalent, call the erload:System.String.Equals method.
The comparison can be further specified by the options parameter, which consists of one or more members of the System.Globalization.CompareOptions enumeration. However, because the purpose of this method is to conduct a culture-sensitive string comparison, the System.Globalization.CompareOptions.Ordinal and System.Globalization.CompareOptions.OrdinalIgnoreCase values have no effect.
Either or both comparands can be null. By definition, any string, including string.Empty, compares greater than a null reference, and two null references compare equal to each other.
The comparison terminates when an inequality is discovered or both strings have been compared. However, if the two strings compare equal to the end of one string, and the other string has characters remaining, the string with the remaining characters is considered greater.