String.Inequality Operator (String, String)


Determines whether two specified strings have different values.

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

public static bool operator !=(
	string a,
	string b


Type: System.String

The first string to compare, or null.

Type: System.String

The second string to compare, or null.

Return Value

Type: System.Boolean

true if the value of a is different from the value of b; otherwise, false.

The Inequality method defines the operation of the inequality operator for the String class. It enables code such as that shown in the Examples section.

The Inequality operator in turn calls the static Equals(String, String) method, which performs an ordinal (case-sensitive and culture-insensitive) comparison.


   The Visual Basic compiler does not resolve the inequality operator as a call to the Inequality method. Instead, the inequality operator wraps a call to the Operators.CompareString method.

The following example demonstrates the inequality operator.

// Example for the String Inequality operator.
using System;

class InequalityOp 
    public static void Main() 
            "This example of the String Inequality operator\n" +
            "generates the following output.\n" );

        CompareAndDisplay( "ijkl" );
        CompareAndDisplay( "ABCD" );
        CompareAndDisplay( "abcd" );

    static void CompareAndDisplay( String Comparand )
        String  Lower = "abcd";

            "\"{0}\" != \"{1}\" ?  {2}",
            Lower, Comparand, Lower != Comparand );

This example of the String Inequality operator
generates the following output.

"abcd" != "ijkl" ?  True
"abcd" != "ABCD" ?  True
"abcd" != "abcd" ?  False

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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