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IEqualityComparer.Equals Method

Determines whether the specified objects are equal.

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

bool Equals(
	Object x,
	Object y
)

Parameters

x
Type: System.Object

The first object to compare.

y
Type: System.Object

The second object to compare.

Return Value

Type: System.Boolean
true if the specified objects are equal; otherwise, false.

ExceptionCondition
ArgumentException

x and y are of different types and neither one can handle comparisons with the other.

Implement this method to provide a customized equality comparison for objects.

Notes to Implementers:

The Equals method is reflexive, symmetric, and transitive. That is, it returns true if used to compare an object with itself; true for two objects x and y if it is true for y and x; and true for two objects x and z if it is true for x and y and also true for y and z.

Implementations are required to ensure that if the Equals method returns true for two objects x and y, then the value returned by the GetHashCode method for x must equal the value returned for y.

The following code example demonstrates the implementation of a case-insensitive IEqualityComparer. In this example, the CaseInsensitiveComparer.Compare method is used to determine whether two objects are equal, based on the provided CultureInfo.

class myCultureComparer : IEqualityComparer
{
    public CaseInsensitiveComparer myComparer;

    public myCultureComparer()
    {
        myComparer = CaseInsensitiveComparer.DefaultInvariant;
    }

    public myCultureComparer(CultureInfo myCulture)
    {
        myComparer = new CaseInsensitiveComparer(myCulture);
    }

    public new bool Equals(object x, object y)
    {
        if (myComparer.Compare(x, y) == 0)
        {
            return true;
        }
        else
        {
            return false;
        }
    }

    public int GetHashCode(object obj)
    {
        return obj.ToString().ToLower().GetHashCode();
    }
}

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0

.NET Compact Framework

Supported in: 3.5, 2.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

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