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Today, I will talk to you about the concept of VB.NET expansion method, which may not be well understood by many people. In order to make you understand better, the editor has summarized the following content for you. I hope you can get something according to this article.

The emergence of VB.NET programming language has played an important role in the development field. Since its emergence, it has developed various versions, and the emergence of each version will bring us a different experience. Let's take a look at the functionality of the VB.NET extension method in the new version.

Visual Basic 9.0 supports the query function integrated by the new generation language, and supports the implementation of relational queries on DLinq data objects or XLinq XML data. These queries are implemented by using a set of methods (or operators) on DLinq or XLinq related objects. Vb9 developers believe that this set of query methods should also be used in existing ways of organizing object data, such as IEnumerable and other collections. Therefore, Visual Basic 9.0 requires the ability to externally add methods to existing types, which is the VB.NET extension method.

The VB.NET extension method is actually a compiler background translation method, which is originally a method that accepts t-type parameters and can be written in the syntax of t-type members. This syntax is only used by class library designers and should not be misused, so visual Basic 9.0 does not provide special syntax support, class library designers only need to put the corresponding Attribute on the modules and methods that declare extension methods.

Module MyExtensionModule MyExtension

_

Public Function Count () Function Count (Of T) ([Me] As

IEnumerable (Of T)) As Integer

For Each Dim item In [Me]

Count + = 1

Next

End Function

End Module

Note that we named the * * parameter of the VB.NET extension method me to remind programmers that after the extension method works, it is just like the instance method me, which is not necessary, but is only a recommended practice.

Extension methods to work, is not without conditions, if everyone extends the methods in framework, it will be a mess. Therefore, it is stipulated that the module where the extension method is located needs to be imported with an imports statement in order for the extension method to work.

After Imports MyExtionsion imports the extension method, you can use it:

Dim arr = {1,2,3,4,5} Dim length = arr.Count 'the above sentence will be automatically translated into' Dim length = MyExtionsion.Count (arr).

As a reminder, the VB.NET extension method is just syntactic sugar. Don't use it if you don't need it. Too many extensions can lead to clear syntax, but bad design. Please consider using this feature carefully.

After reading the above, do you have any further understanding of the concept of VB.NET extension methods? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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