Information
The topic you requested is included in another documentation set. For convenience, it's displayed below. Choose Switch to see the topic in its original location.

String.Compare Method (String, Int32, String, Int32, Int32, StringComparison)

Compares substrings of two specified String objects.

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

public static int Compare (
	string strA,
	int indexA,
	string strB,
	int indexB,
	int length,
	StringComparison comparisonType
)
public static int Compare (
	String strA, 
	int indexA, 
	String strB, 
	int indexB, 
	int length, 
	StringComparison comparisonType
)
public static function Compare (
	strA : String, 
	indexA : int, 
	strB : String, 
	indexB : int, 
	length : int, 
	comparisonType : StringComparison
) : int
Not applicable.

Parameters

strA

The first String object.

indexA

The position of the substring within strA.

strB

The second String object.

indexB

The position of the substring within strB.

length

The maximum number of characters in the substrings to compare.

comparisonType

One of the StringComparison values.

Return Value

A 32-bit signed integer indicating the lexical relationship between the two comparands.

Value

Condition

Less than zero

The substring in the strA parameter is less than the substring in the strB parameter.

Zero

The substrings are equal, or the length parameter is zero.

Greater than zero

The substring in strA is greater than the substring in strB.

Exception typeCondition

ArgumentOutOfRangeException

indexA is greater than strA.Length.

-or-

indexB is greater than strB.Length.

-or-

indexA, indexB, or length is negative.

-or-

Either indexA or indexB is a null reference (Nothing in Visual Basic), and length is greater than zero.

ArgumentException

comparisonType is not a StringComparison value.

The substrings to compare start at strA plus indexA, and strB plus indexB. The length of the first substring is the length of strA minus indexA, and the length of the second substring is the length of strB minus indexB.

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 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 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 substrings 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".

 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:

 static bool IsFileURI(String path)
 { 
    return (String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) == 0);
 }

The following code example compares two substrings.

// Sample for String.Compare(String, Int32, String, Int32, Int32)
using System;

class Sample {
    public static void Main() {
//                 0123456
    String str1 = "machine";
    String str2 = "device";
    String str;
    int result;

    Console.WriteLine();
    Console.WriteLine("str1 = '{0}', str2 = '{1}'", str1, str2);
    result = String.Compare(str1, 2, str2, 0, 2);
    str = ((result < 0) ? "less than" : ((result > 0) ? "greater than" : "equal to"));
    Console.Write("Substring '{0}' in '{1}' is ", str1.Substring(2, 2), str1);
    Console.Write("{0} ", str);
    Console.WriteLine("substring '{0}' in '{1}'.", str2.Substring(0, 2), str2);
    }
}
/*
This example produces the following results:

str1 = 'machine', str2 = 'device'
Substring 'ch' in 'machine' is less than substring 'de' in 'device'.
*/

// Sample for String.Compare(String, Int32, String, Int32, Int32)
import System.*;

class Sample
{
    public static void main(String[] args)
    {
        //                 0123456
        String str1 = "machine";
        String str2 = "device";
        String str;
        int result;

        Console.WriteLine();
        Console.WriteLine("str1 = '{0}', str2 = '{1}'", str1, str2);
        result = String.Compare(str1, 2, str2, 0, 2);
        str = result < 0 ? "less than" : (result > 0) ? "greater than" : 
            "equal to";
        Console.Write("Substring '{0}' in '{1}' is ", str1.Substring(2, 2), 
            str1);
        Console.Write("{0} ", str);
        Console.WriteLine("substring '{0}' in '{1}'.", str2.Substring(0, 2), 
            str2);
    } //main
} //Sample
/*
This example produces the following results:

str1 = 'machine', str2 = 'device'
Substring 'ch' in 'machine' is less than substring 'de' in 'device'.
*/

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0

.NET Compact Framework

Supported in: 2.0

XNA Framework

Supported in: 1.0

Community Additions

Show:
© 2014 Microsoft