Tuple(Of T1, T2, T3, T4, T5).IStructuralEquatable.Equals Method
Returns a value that indicates whether the current Tuple(Of T1, T2, T3, T4, T5) object is equal to a specified object based on a specified comparison method.
Assembly: mscorlib (in mscorlib.dll)
'Declaration Private Function Equals ( _ other As Object, _ comparer As IEqualityComparer _ ) As Boolean Implements IStructuralEquatable.Equals
Parameters
- other
- Type: System.Object
The object to compare with this instance.
- comparer
- Type: System.Collections.IEqualityComparer
An object that defines the method to use to evaluate whether the two objects are equal.
Return Value
Type: System.Booleantrue if the current instance is equal to the specified object; otherwise, false.
Implements
IStructuralEquatable.Equals(Object, IEqualityComparer)This member is an explicit interface member implementation. It can be used only when the Tuple(Of T1, T2, T3, T4, T5) instance is cast to an IStructuralEquatable interface.
The IEqualityComparer.Equals implementation is called only if other is not Nothing, and if it can be successfully cast (in C#) or converted (in Visual Basic) to a Tuple(Of T1, T2, T3, T4, T5) object whose components are of the same types as the current instance. The IStructuralEquatable.Equals(Object, IEqualityComparer) method first passes the Item1 values of the Tuple(Of T1, T2, T3, T4, T5) objects to be compared to the IEqualityComparer.Equals implementation. If this method call returns true, the method is called again and passed the Item2 values of the two Tuple(Of T1, T2, T3, T4, T5) objects. This continues until the method call returns false when it compares a specific pair of Item values, or the two Item5 values are passed to the method.
The following example defines a DoubleComparer class that implements the IEqualityComparer interface. The example instantiates two Tuple(Of T1, T2, T3, T4, T5) objects by using a random number generator to populate their second through fifth components, casts the first instance to an IStructuralEquatable interface, and then uses a DoubleComparer object to test the two Tuple(Of T1, T2, T3, T4, T5) objects for approximate equality.
Imports System.Collections Public Class DoubleComparer(Of T1, T2, T3, T4, T5) : Implements IEqualityComparer Private difference As Double Private argument As Integer = 0 Public Sub New(difference As Double) Me.difference = difference End Sub Public Overloads Function Equals(x As Object, y As Object) As Boolean _ Implements IEqualityComparer.Equals argument += 1 ' Return true for Item1. If argument = 1 Then Return True Else Dim d1 As Double = CDbl(x) Dim d2 As Double = CDbl(y) If d1 - d2 < d1 * difference Then Return True Else Return False End If End If End Function Public Overloads Function GetHashCode(obj As Object) As Integer _ Implements IEqualityComparer.GetHashCode If TypeOf obj Is T1 Then Return CType(obj, T1).GetHashCode() ElseIf TypeOf obj Is T2 Then Return CType(obj, T2).GetHashCode() ElseIf TypeOf obj Is T3 Then Return CType(Obj, T3).GetHashCode() ElseIf TypeOf obj Is T4 Then Return CType(Obj, T4).GetHashCode() Else Return CType(obj, T5).GetHashCode() End If End Function End Class Module Example Public Sub Main() Dim value1 = GetValues(1) Dim value2 = GetValues(2) Dim iValue1 As IStructuralEquatable = value1 Console.WriteLine("{0} ={3}{1} :{3}{2}", value1, value2, _ iValue1.Equals(value2, _ New DoubleComparer(Of Integer, Double, Double, Double, Double)(.01)), _ vbCrLf) End Sub Private Function GetValues(ctr As Integer) As Tuple(Of Integer, Double, Double, Double, Double) ' Generate four random numbers between 0 and 1 Dim rnd As New Random(CInt((DateTime.Now.Ticks >> 32) >> ctr)) Return Tuple.Create(ctr, rnd.NextDouble(), rnd.NextDouble(), rnd.NextDouble(), rnd.NextDouble) End Function End Module ' The example displays output like the following: ' (1, 0.910850029862882, 0.894596965934428, 0.319678635019659, 0.801647342649124) = ' (2, 0.818546649915421, 0.355961162762698, 0.0438506622071614, 0.679904267042831) : ' False
Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
