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UriTemplateEquivalenceComparer Class
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UriTemplateEquivalenceComparer Class

A class used to compare UriTemplate instances for structural (instead of reference) equivalence.


Namespace:  System
Assembly:  System.ServiceModel (in System.ServiceModel.dll)

Public Class UriTemplateEquivalenceComparer _
	Implements IEqualityComparer(Of UriTemplate)

The UriTemplateEquivalenceComparer type exposes the following members.

Public methodUriTemplateEquivalenceComparerInitializes a new instance of the UriTemplateEquivalenceComparer class.

Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Public methodEquals(UriTemplate, UriTemplate)Compares two UriTemplate instances for equivalence.
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetHashCode(UriTemplate)Gets a hash code for the specified UriTemplate instance.
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)

UriTemplate instances are compared using reference equality by default. The UriTemplateEquivalenceComparer class evaluates equivalence using IsEquivalentTo(UriTemplate) instead of the default reference equality check. This class is useful when you wish to compare two UriTemplate instances based on the URIs they match instead of strict reference equality.

The following example shows the difference between reference equality and structural equality. It also shows how to use the UriTemplateEquivalenceComparer as a comparer in a dictionary.

'Define two structurally equivalent templates 
Dim temp1 As UriTemplate = New UriTemplate("weather/{state}/{city}")
Dim temp2 As UriTemplate = New UriTemplate("weather/{country}/{village}")

'Notice they are not reference equal, in other words 
'they are do not refer to the same object 
If temp1.Equals(temp2) Then
    Console.WriteLine("{0} and {1} are reference equal", temp1, temp2)
    Console.WriteLine("{0} and {1} are NOT reference equal", temp1, temp2)
End If 

'Notice they are structrually equal 
If (temp1.IsEquivalentTo(temp2)) Then
    Console.WriteLine("{0} and {1} are structurally equal", temp1, temp2)
    Console.WriteLine("{0} and {1} are NOT structurally equal", temp1, temp2)
End If 

'Create a dictionary and use UriTemplateEquivalenceComparer as the comparer 
Dim templates As Dictionary(Of UriTemplate, Object) = New Dictionary(Of UriTemplate, Object)(New UriTemplateEquivalenceComparer())

'Add template 1 into the dictionary
templates.Add(temp1, "template1")

'The UriTemplateEquivalenceComparer will be used here to compare the template in the table with template2 
'they are structurally equivalent, so ContainsKey will return true. 
If (templates.ContainsKey(temp2)) Then
    Console.WriteLine("Both templates hash to the same value")
    Console.WriteLine("Both templates do NOT hash to the same value")
End If

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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