String::Compare Method (String^, Int32, String^, Int32, Int32, Boolean, CultureInfo^)
Compares substrings of 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)
public: static int Compare( String^ strA, int indexA, String^ strB, int indexB, int length, bool ignoreCase, CultureInfo^ culture )
Parameters
- strA
-
Type:
System::String^
The first string to use in the comparison.
- indexA
-
Type:
System::Int32
The position of the substring within strA.
- strB
-
Type:
System::String^
The second string to use in the comparison.
- indexB
-
Type:
System::Int32
The position of the substring within strB.
- length
-
Type:
System::Int32
The maximum number of characters in the substrings to compare.
- ignoreCase
-
Type:
System::Boolean
true to ignore case during the comparison; otherwise, false.
- culture
-
Type:
System.Globalization::CultureInfo^
An object that supplies culture-specific comparison information.
Return Value
Type: System::Int32An integer that indicates the lexical relationship between the two comparands.
Value | Condition |
|---|---|
Less than zero | The substring in strA precedes the substring in strB in the sort order. |
Zero | The substrings occur in the same position in the sort order, or length is zero. |
Greater than zero | The substring in strA follows the substring in strB in the sort order. |
| Exception | Condition |
|---|---|
| ArgumentOutOfRangeException | |
| ArgumentNullException | culture is null. |
The substrings to compare start in strA at indexA, and in strB at indexB. Both indexA and indexB are zero-based; that is, the first character in strA and strB is at position zero, not position one. The length of the first substring is equal to the length of strA minus indexA plus one. The length of the second substring is equal to the length of strB minus indexB plus one.
The number of characters to compare is the lesser of the lengths of the two substrings, and length. The indexA, indexB, and length parameters must be nonnegative.
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 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 substrings 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".
static bool IsFileURI(String^ path) { return (String::Compare(path, 0, "file:", 0, 5, true) == 0); }
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 Compare(String^, Int32, String^, Int32, Int32, Boolean, CultureInfo^) method does not consider these characters when it performs a linguistic or culture-sensitive comparison. To recognize ignorable characters in your comparison, call the Compare(String^, Int32, String^, Int32, Int32, CultureInfo^, CompareOptions) method and supply a value of CompareOptions::Ordinal or CompareOptions::OrdinalIgnoreCase for the options parameter.
The following example compares two substrings using different cultures and ignoring the case of the substrings. The choice of culture affects how the letter "I" is compared.
// Sample for String::Compare(String, Int32, String, Int32, Int32, Boolean, CultureInfo) using namespace System; using namespace System::Globalization; int main() { // 0123456 String^ str1 = "MACHINE"; String^ str2 = "machine"; String^ str; int result; Console::WriteLine(); Console::WriteLine( "str1 = '{0}', str2 = '{1}'", str1, str2 ); Console::WriteLine( "Ignore case, Turkish culture:" ); result = String::Compare( str1, 4, str2, 4, 2, true, gcnew CultureInfo( "tr-TR" ) ); str = ((result < 0) ? "less than" : ((result > 0) ? (String^)"greater than" : "equal to")); Console::Write( "Substring '{0}' in '{1}' is ", str1->Substring( 4, 2 ), str1 ); Console::Write( " {0} ", str ); Console::WriteLine( "substring '{0}' in '{1}'.", str2->Substring( 4, 2 ), str2 ); Console::WriteLine(); Console::WriteLine( "Ignore case, invariant culture:" ); result = String::Compare( str1, 4, str2, 4, 2, true, CultureInfo::InvariantCulture ); str = ((result < 0) ? "less than" : ((result > 0) ? (String^)"greater than" : "equal to")); Console::Write( "Substring '{0}' in '{1}' is ", str1->Substring( 4, 2 ), str1 ); Console::Write( " {0} ", str ); Console::WriteLine( "substring '{0}' in '{1}'.", str2->Substring( 4, 2 ), str2 ); } /* This example produces the following results: str1 = 'MACHINE', str2 = 'machine' Ignore case, Turkish culture: Substring 'IN' in 'MACHINE' is less than substring 'in' in 'machine'. Ignore case, invariant culture: Substring 'IN' in 'MACHINE' is equal to substring 'in' in 'machine'. */
Available since 1.1