Tuple<T1, T2, T3, T4, T5>.IStructuralEquatable.Equals Method

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.Boolean
true if the current instance is equal to the specified object; otherwise, false.

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(ByVal difference As Double)
      Me.difference = difference
   End Sub

   Public Overloads Function Equals(ByVal x As Object, ByVal 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(ByVal 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 Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      Dim value1 = GetValues(1)
      Dim value2 = GetValues(2)
      Dim iValue1 As IStructuralEquatable = value1
      outputBlock.Text += String.Format("{0} ={3}{1} :{3}{2}", value1, value2, _
                        iValue1.Equals(value2, _
                        New DoubleComparer(Of Integer, Double, Double, Double, Double)(0.01)), _
                        vbCrLf) & vbCrLf
   End Sub

   Private Function GetValues(ByVal 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

using System;
using System.Collections;

public class DoubleComparer<T1, T2, T3, T4, T5> : IEqualityComparer
{
   private double difference;
   private int argument = 0;

   public DoubleComparer(double difference)
   {
      this.difference = difference;
   }

   new public bool Equals(object x, object y)
   {
      argument += 1;

      // Return true for Item1.
      if (argument == 1) return true;

      double d1 = (double)x;
      double d2 = (double)y;

      if (d1 - d2 < d1 * difference)
         return true;
      else
         return false;
   }

   public int GetHashCode(object obj)
   {
      if (obj is T1)
         return ((T1)obj).GetHashCode();
      else if (obj is T2)
         return ((T2)obj).GetHashCode();
      else if (obj is T3)
         return ((T3)obj).GetHashCode();
      else if (obj is T4)
         return ((T4)obj).GetHashCode();
      else
         return ((T5)obj).GetHashCode();
   }
}

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      var value1 = GetValues(1);
      var value2 = GetValues(2);
      IStructuralEquatable iValue1 = value1;
      outputBlock.Text += String.Format("{0} =\n{1} :\n{2}", value1, value2,
                        iValue1.Equals(value2,
                        new DoubleComparer<int, double, double, double, double>(.01))) + "\n";
   }

   private static Tuple<int, double, double, double, double> GetValues(int ctr)
   {
      // Generate four random numbers between 0 and 1
      Random rnd = new Random((int)DateTime.Now.Ticks >> 32 >> ctr);
      return Tuple.Create(ctr, rnd.NextDouble(), rnd.NextDouble(),
                          rnd.NextDouble(), rnd.NextDouble());
   }
}