Reflection is a mechanism for dynamically checking and operating types and their members at runtime. Its core uses include: 1. Obtain type information and create instances dynamically; 2. Dynamically call methods and access attributes, including private members; 3. Check the types in the assembly, suitable for plug-in systems, serialization libraries and other scenarios. Common usage methods include loading DLL to create objects, traversing attributes for unified processing, calling private methods, etc. However, the reflection performance is low, and the main problems include slow first calls, slower frequent calls, and inability to optimize inline. Therefore, it is recommended to cache the reflection results, use delegate calls or alternatives to improve efficiency. The rational use of reflection can balance flexibility and performance.

Pattern matching in C# makes the conditional logic more concise and expressive through is expressions and switch expressions. 1. Use the is expression to perform concise type checks, such as if (objisstrings), and extract values ??at the same time; 2. Use logical modes (and, or, not) to simplify conditional judgments, such as valueis>0and

Extension methods allow "add" methods to them without modifying the type or creating derived classes. They are static methods defined in static classes, called through instance method syntax, and the first parameter specifies the extended type using this keyword. For example, the IsNullOrEmpty extension method can be defined for the string type and called like an instance method. The defining steps include: 1. Create a static class; 2. Defining a static method; 3. Add this before the first parameter; 4. Call using the instance method syntax. Extension methods are suitable for enhancing the readability of existing types, types that cannot be modified by operations, or build tool libraries, and are commonly found in LINQ. Note that it cannot access private members, and the latter is preferred when conflicts with the instance method of the same name. Response

TheyieldkeywordinC#simplifiesiteratorcreationbyautomaticallygeneratingastatemachinethatenableslazyevaluation.1.Itallowsreturningitemsoneatatimeusingyieldreturn,pausingexecutionbetweeneachitem,whichisidealforlargeordynamicsequences.2.yieldbreakcanbeus

The role of IDisposable and using in C# is to efficiently and deterministically manage unmanaged resources. 1. IDisposable provides Dispose() method, so that the class can clearly define how to release unmanaged resources; 2. The using statement ensures that Dispose() is automatically called when the object is out of scope, simplifying resource management and avoiding leakage; 3. When using it, please note that the object must implement IDisposable, can declare multiple objects, and should always use using for types such as StreamReader; 4. Common best practices include not relying on destructors to clean up, correctly handling nested objects, and implementing the Dispose(bool) pattern.

DependencyInjection(DI)inC#isadesignpatternthatenhancesmodularity,testability,andmaintainabilitybyallowingclassestoreceivedependenciesexternally.1.DIpromotesloosecouplingbydecouplingobjectcreationfromusage.2.Itsimplifiestestingthroughmockobjectinject

LambdaexpressionsandLINQsimplifydatamanipulationinC#byenablingconcise,readable,andefficientcode.1.Lambdaexpressionsallowinlinefunctiondefinitions,makingiteasiertopasslogicasargumentsforfiltering,transforming,sorting,andaggregatingdatadirectlywithinme

Span and Memory improve C# performance by reducing memory allocation. 1. Span avoids array copying and provides light references to existing memory, which is suitable for parsing binary protocols, string operations and high-performance buffer management; 2. Memory supports passing memory slices across asynchronous methods, which is suitable for scenarios where more flexible life cycles are required; 3. Both reduce GC pressure, optimize performance by reusing buffers and avoiding temporary copying; 4. Span is limited to use on the stack and cannot be stored in classes or used in asynchronous methods. Be careful to avoid reassignment operations such as calling.ToArray().