String.Compare Method (String, String, CultureInfo, CompareOptions)
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.
Assembly: mscorlib (in mscorlib.dll)
static member Compare : strA:string * strB:string * culture:CultureInfo * options:CompareOptions -> int
- Type: System.String
The first string to compare.
- Type: System.String
The second string to compare.
- Type: System.Globalization.CultureInfo
The culture that supplies culture-specific comparison information.
- Type: System.Globalization.CompareOptions
Options to use when performing the comparison (such as ignoring case or symbols).
Return ValueType: System.Int32
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 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 Equals method.
The comparison can be further specified by the options parameter, which consists of one or more members of the CompareOptions enumeration. However, because the purpose of this method is to conduct a culture-sensitive string comparison, the CompareOptions.Ordinal and CompareOptions.OrdinalIgnoreCase values have no effect.
Either or both comparands can be a null reference (Nothing in Visual Basic). 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.Notes to Callers
Character sets include ignorable characters, which are characters that are not considered when performing a linguistic or culture-sensitive comparison. The method does not consider such characters when it performs a culture-sensitive comparison. To recognize ignorable characters in your comparison, supply a value of CompareOptions.Ordinal or CompareOptions.OrdinalIgnoreCase for the options parameter.
The following example compares two strings in three different ways: using linguistic comparison for the en-US culture; using linguistic case-sensitive comparison for the en-US culture; and using an ordinal comparison. It illustrates how the three methods of comparison produce three different results.