IStructuralEquatable.Equals Method

July 28, 2014

Determines whether an object is structurally equal to the current instance.

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

bool Equals(
	Object other,
	IEqualityComparer comparer
)

Parameters

other
Type: System.Object
The object to compare with the current instance.
comparer
Type: System.Collections.IEqualityComparer
An object that determines whether the current instance and other are equal.

Return Value

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

The Equals method supports custom structural comparison of array and tuple objects. This method in turn calls the comparer object's IEqualityComparer.Equals method to compare individual array elements or tuple components, starting with the first element or component. The individual calls to IEqualityComparer.Equals end and the IStructuralEquatable.Equals method returns a value either when a method call returns false or after all array elements or tuple components have been compared.

The default equality comparer, EqualityComparer<Object>.Default.Equals, considers two NaN values to be equal. In some cases, however, you may want the comparison of NaN values for equality to return false, which indicates that the values cannot be compared. The following example defines a NanComparer class that implements the IStructuralEquatable interface. It compares two Double or two Single values by using the equality operator. It passes values of any other type to the default equality comparer.

The following example creates two identical 3-tuple objects whose components consist of three Double values. The value of the second component is Double.NaN. The example then calls the Tuple<T1, T2, T3>.Equals method, and it calls the IStructuralEquatable.Equals method twice. The first time, it passes the default equality comparer that is returned by the EqualityComparer<T>.Default property. The second time, it passes the custom NanComparer object. As the output from the example shows, the first two method calls return true, whereas the third call returns false.

Windows Phone OS

Supported in: 8.1, 8.0

Show:
© 2014 Microsoft