String.Compare Method (String, String, Boolean, CultureInfo)
Compares two specified String objects, ignoring or honoring their case, and using culture-specific information to influence the comparison, and returns an integer that indicates their relative position in the sort order.
Assembly: mscorlib (in mscorlib.dll)
static member Compare : strA:string * strB:string * ignoreCase:bool * culture:CultureInfo -> int
- Type: System.String
The first string to compare.
- Type: System.String
The second string to compare.
- Type: System.Boolean
true to ignore case during the comparison; otherwise, false.
- Type: System.Globalization.CultureInfo
An object that supplies culture-specific comparison information.
Return ValueType: System.Int32
A 32-bit signed integer that indicates the lexical relationship between the two comparands.
Less than zero
strA precedes strB in the sort order.
strA occurs in the same position as strB in the sort order.
Greater than zero
strA follows strB in the sort order.
culture is a null reference (Nothing in Visual Basic).
The comparison uses the culture parameter to obtain culture-specific information such as casing rules and the alphabetic order of individual characters. For example, a culture could specify that certain combinations of characters be treated as a single character, or uppercase and lowercase characters be compared in a particular way, or that the sorting order of a character depends on the characters that precede or follow it.
The comparison is performed using word sort rules. For more information about word, string, and ordinal sorts, see System.Globalization.CompareOptions.
One or both comparands can be a null reference (Nothing in Visual Basic). 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, then 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".
Compare the path name to "file" using an ordinal comparison. The correct code to do this is as follows:Notes to Callers
Character sets include ignorable characters. The method does not consider such characters when it performs a culture-sensitive comparison. For example, if the following code is run on the .NET Framework 4 or later, a case-insensitive comparison of "animal" with "Ani-mal" (using a soft hyphen, or U+00AD) using the invariant culture indicates that the two strings are equivalent.
The following example demonstrates how culture can affect a comparison. In Czech - Czech Republic culture, "ch" is a single character that is greater than "d". However, in English - United States culture, "ch" consists of two characters, and "c" is less than "d".