Four common "anti-pattern" problems in C# development need to be avoided. First, the unreasonable use of async/await leads to deadlocks or performance degradation. We should adhere to the principle of full asynchronousness, configure ConfigureAwait(false) and standardize naming; second, excessive dependence on var affects readability, and explicitly declare and unify team specifications when the type is unclear; third, the incorrect use of Dispose and resource management causes leakage, and the use statements should be used correctly and the IDisposable standard mode should be implemented; fourth, the abuse of static classes or singletons causes testing difficulties, and priority should be given to dependency injection, statelessness, or the life cycle managed by containers. Avoiding these misunderstandings can significantly improve code quality and maintenance.

During the C# development process, although the language itself is well designed and powerful, developers may still fall into some common pitfalls due to insufficient experience or habits. These errors are often not syntactic, but are “anti-patterns” in architectural design, code organization or resource management. Avoiding these problems can significantly improve code quality and project maintenance.

1. Unreasonable use of async/await causes deadlock or performance degradation

Many people encounter deadlocks when using asynchronous programming or do not really take advantage of asynchronous. For example, calling .Result or .Wait() in a UI thread can easily cause deadlocks, especially in WinForm or WPF applications.

Common errors:

• Abuse of .Result in asynchronous methods
• Ignore configuration ConfigureAwait(false) to cause context capture
• Asynchronous method naming is not standardized (if not ending with Async )

Suggested practices:

• Adhere to the principle of "full asynchronous" and use async/await from top to bottom
• Use ConfigureAwait(false) in class library to avoid unnecessary context capture
• Avoid mixing .Wait() or .Result in asynchronous methods

2. Over-dependence on var and implicit type inference

The var keyword in C# is indeed convenient, but if abused, it will cause the code to be less readable. Especially when the variable type is not obvious, it will make it difficult for other developers to understand the intention.

Typical scenarios:

• var result = SomeComplexMethod(); (I don't know what type to return)
• No explicit comments or documentation when using anonymous types
• Use var in a loop to hide the actual type information (for example, iterate over IEnumerable<string></string> but write it as var item )

Suggested practices:

• Explicitly declare a type when it is not obvious or easily misunderstood
• Add comments to variables of complex objects or anonymous types to illustrate structure
• Unified standards for var use within the team

3. Incorrect use of Dispose , using and resource management

Many developers have insufficient understanding of the IDisposable interface, resulting in resource leakage or repeated release. This type of problem is very common especially when dealing with resources such as files, database connections, network requests, etc.

Common omissions:

• Forgot to call Dispose() manually
• Multiple resources are not properly wrapped in using block when nested
• When implementing IDisposable in a class, the standard pattern is not followed (such as the Finalizer is not processed)

Suggested practices:

• Any object that implements IDisposable should be processed using using statements.
• Multiple resources can be nested with multiple using statements, or simplified writing in C#8
• Implement IDisposable correctly when customizing resource classes and consider whether Finalizer is needed

4. Abuse of static classes or singletons makes testing difficult

For convenience, many developers like to make tool classes and service classes into static classes or global singletons, but this makes unit testing difficult and violates the principle of dependency injection.

Typical problems:

• Static class cannot be mocked, affecting test coverage
• Singleton holds state, resulting in abnormal behavior in multithreaded environment
• Strong coupling between classes, difficult to replace and implement

Suggested practices:

• Try to use dependency injection instead of directly accessing static classes or singletons
• The tool class should be kept stateless as much as possible, otherwise it should be used as a normal instance class.
• If a singleton must be used, consider managing the lifecycle through containers

Basically, these common "pit points" in C# development. Some may seem minor issues, but in the long run it will affect the maintainability and stability of the project. Avoiding these anti-patterns will allow you to write clearer, safer, and easier to extend C# code.

The above is the detailed content of What are some common pitfalls or anti-patterns to avoid when developing with C#?. For more information, please follow other related articles on the PHP Chinese website!