Microsoft .NET Code Analysis: Utilize the Pattern Matching ‘not’ Operator

Throughout my experience with C# coding, I’ve never been particularly fond of the ‘!‘ (bang) operator. This is mainly because it can easily go unnoticed when reviewing code, as demonstrated in this example from the EntityFramework source code:

if (!(context.ParameterValues[baseParameterName] is 
    IEnumerable<TEntity> baseListParameter))
{
    return null;
}

Instead, I have consistently opted for using ‘= false.’ However, since the introduction of C# 9, the ‘not‘ operator can now be employed instead, as illustrated below:

if (context.ParameterValues[baseParameterName] is not 
    IEnumerable<TEntity> baseListParameter)
{
    return null;
}

Do you not find that using pattern matching enhances readability?

This is related to violation IDE0083 and this is how I have it setup in my .editorConfig: dotnet_diagnostic.IDE0083.severity = warning

Summary

While reviewing the Entity Framework codebase I utilized for this article, I discovered 5 occurrences where the code needs to be fixed.

For further guidance and insights, I highly recommend obtaining a copy of my book, “Rock Your Code: Coding Standards for Microsoft .NET” available on Amazon.com. Additionally, to explore more performance tips for .NET, I encourage you to acquire the 3rd edition of “Rock Your Code: Code & App Performance for Microsoft .NET” also available on Amazon.com.

To analyze your code using the same settings I used in these articles, I encourage you to incorporate my EditorConfig file. It can be found at the following link: https://bit.ly/dotNetDaveEditorConfig. I update this file quarterly, so remember to keep yours up to date as well. I hope you will check out my OSS project Spargine by using this link: https://bit.ly/Spargine.

Please feel free to leave a comment below. I would appreciate hearing your thoughts and feedback.

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