IComparer<T>.Compare(T, T) Method

Reference

Definition

Namespace:: System.Collections.Generic

Assembly:: System.Runtime.dll

Assembly:: mscorlib.dll

Assembly:: netstandard.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Compares two objects and returns a value indicating whether one is less than, equal to, or greater than the other.

public:
 int Compare(T x, T y);

public int Compare (T x, T y);

public int Compare (T? x, T? y);

abstract member Compare : 'T * 'T -> int

Public Function Compare (x As T, y As T) As Integer

Parameters

x: T

The first object to compare.

y: T

The second object to compare.

Returns

Int32

A signed integer that indicates the relative values of x and y, as shown in the following table.

Value	Meaning
Less than zero	`x` is less than `y`.
Zero	`x` equals `y`.
Greater than zero	`x` is greater than `y`.

Examples

The following example implements the IComparer<T> interface to compare objects of type Box according to their dimensions. This example is part of a larger example provided for the Comparer<T> class.

// This class is not demonstrated in the Main method
// and is provided only to show how to implement
// the interface. It is recommended to derive
// from Comparer<T> instead of implementing IComparer<T>.
public class BoxComp : IComparer<Box>
{
    // Compares by Height, Length, and Width.
    public int Compare(Box x, Box y)
    {
        if (x.Height.CompareTo(y.Height) != 0)
        {
            return x.Height.CompareTo(y.Height);
        }
        else if (x.Length.CompareTo(y.Length) != 0)
        {
            return x.Length.CompareTo(y.Length);
        }
        else if (x.Width.CompareTo(y.Width) != 0)
        {
            return x.Width.CompareTo(y.Width);
        }
        else
        {
            return 0;
        }
    }
}

' This class is not demonstrated in the Main method
' and is provided only to show how to implement
' the interface. It is recommended to derive
' from Comparer<T> instead of implementing IComparer<T>.
Public Class BoxComp
    Implements IComparer(Of Box)
    ' Compares by Height, Length, and Width.
    Public Function Compare(ByVal x As Box, ByVal y As Box) As Integer Implements _
                                                IComparer(Of Box).Compare
        If x.Height.CompareTo(y.Height) <> 0 Then
            Return x.Height.CompareTo(y.Height)
        ElseIf x.Length.CompareTo(y.Length) <> 0 Then
            Return x.Length.CompareTo(y.Length)
        ElseIf x.Width.CompareTo(y.Width) <> 0 Then
            Return x.Width.CompareTo(y.Width)
        Else
            Return 0
        End If
    End Function
End Class

Remarks

Implement this method to provide a customized sort order comparison for type T.

Comparing null with any reference type is allowed and does not generate an exception. A null reference is considered to be less than any reference that is not null.

Applies to

Share via