Enumerable::SequenceEqual<TSource> Method (IEnumerable<TSource>, IEnumerable<TSource>)
Determines whether two sequences are equal by comparing the elements by using the default equality comparer for their type.
Namespace: System.Linq
Assembly: System.Core (in System.Core.dll)
Type Parameters
- TSource
The type of the elements of the input sequences.
Parameters
- first
- Type: System.Collections.Generic::IEnumerable<TSource>
An IEnumerable<T> to compare to second.
- second
- Type: System.Collections.Generic::IEnumerable<TSource>
An IEnumerable<T> to compare to the first sequence.
Return Value
Type: System::Booleantrue if the two source sequences are of equal length and their corresponding elements are equal according to the default equality comparer for their type; otherwise, false.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable<TSource>. When you use instance method syntax to call this method, omit the first parameter.| Exception | Condition |
|---|---|
| ArgumentNullException | first or second is nullptr. |
The SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) method enumerates the two source sequences in parallel and compares corresponding elements by using the default equality comparer for TSource, Default. The default equality comparer, Default, is used to compare values of the types that implement the IEqualityComparer<T> generic interface. To compare a custom data type, you need to implement this interface and provide your own GetHashCode and Equals methods for the type.
The following code examples demonstrate how to use SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) to determine whether two sequences are equal. In the first two examples, the method determines whether the compared sequences contain references to the same objects. In the third and fourth examples, the method compares the actual data of the objects within the sequences.
In this example the sequences are equal.
The following code example compares two sequences that are not equal. Note that the sequences contain identical data, but because the objects that they contain have different references, the sequences are not considered equal.
If you want to compare the actual data of the objects in the sequences instead of just comparing their references, you have to implement the IEqualityComparer<T> generic interface in your class. The following code example shows how to implement this interface in a custom data type and provide GetHashCode and Equals methods.
After you implement this interface, you can use sequences of Product objects in the SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) method, as shown in the following example.
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