Compares two specified string objects using the specified rules, and returns an integer that indicates their relative position in the sort order.
A 32-bit signed integer that indicates the lexical relationship between the two comparands.
Less than zero
strA is less than strB.
strA equals strB.
Greater than zero
strA is greater than strB.
The comparisonType parameter indicates whether the comparison should use the current or invariant culture, honor or ignore the case of the comparands, or use word (culture-sensitive) or ordinal (culture-insensitive) sort rules.
One or both comparands can be null. By definition, any string, including the empty string (""), 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 remaining characters is considered greater. The return value is the result of the last comparison performed.
Unexpected results can occur when comparisons are affected by culture-specific casing rules. For example, in Turkish, the following example yields the wrong results because the file system in Turkish does not use linguistic casing rules for the letter "i" in "file".
code reference: System.String.Compare#16
Compare the path name to "file" using an ordinal comparison. The correct code to do this is as follows:
code reference: System.String.Compare#17