Tuple<T1>.IStructuralEquatable.Equals(Object, IEqualityComparer) Method

Definition

Returns a value that indicates whether the current Tuple<T1> object is equal to a specified object based on a specified comparison method.

bool IStructuralEquatable.Equals (object other, System.Collections.IEqualityComparer comparer);

Parameters

other
Object

The object to compare with this instance.

comparer
IEqualityComparer

An object that defines the method to use to evaluate whether the two objects are equal.

Returns

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

Implements

Examples

The following example defines an IEqualityComparer implementation that considers two floating-point values to be equal if they are approximately equal to each other (that is, if one value is within .01 percent of the other).

using System;
using System.Collections;

public class Tuple1Comparer : IEqualityComparer
{
   new public bool Equals(object x, object y)
   {
      // Check if x is a floating point type. If x is, then y is.
      if (x is double | x is float)
      {   
         // Convert to Double values.
         double dblX = (double) x;
         double dblY = (double) y;
         if (Double.IsNaN(dblX) | Double.IsInfinity(dblX) |
             Double.IsNaN(dblY) | Double.IsInfinity(dblY)) 
            return dblX.Equals(dblY);   
         else
            return Math.Abs(dblX - dblY) <= dblX * .0001;
      }
      else
      {
         return x.Equals(y);
      }
   }
   
   public int GetHashCode(object obj)
   {
      return obj.GetHashCode();
   }
}

public class Example
{
   public static void Main()
   {
      var doubleTuple1 = Tuple.Create(12.3455);

      var doubleTuple2 = Tuple.Create(16.8912);
      var doubleTuple3 = Tuple.Create(12.3449599);

      // Compare first tuple with a Tuple<double> with a different value.
      TestEquality(doubleTuple1, doubleTuple2);
      //Compare first tuple with a Tuple<double> with the same value.
      TestEquality(doubleTuple1, doubleTuple3);
   }

   private static void TestEquality(Tuple<double> tuple, object obj)
   {
      Console.WriteLine("{0} = {1}: {2}", tuple.ToString(),
                                             obj.ToString(),
                                             ((IStructuralEquatable)tuple).Equals(obj, new Tuple1Comparer()));
   }
}
// The example displays the following output:
//       (12.3455) = (16.8912): False
//       (12.3455) = (12.3449599): True

Remarks

This member is an explicit interface member implementation. It can be used only when the Tuple<T1> instance is cast to an IStructuralEquatable interface.

The IEqualityComparer.Equals implementation is called only if other is not null, and if it can be successfully cast (in C#) or converted (in Visual Basic) to a Tuple<T1> object whose single component is of the same type as the current instance. The method is passed the Item1 component of the current instance and the Item1 component of the Tuple<T1> object represented by the other parameter.

Applies to

Produkt Verze
.NET Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 2.0, 2.1
UWP 10.0

See also