What is the overloading capability of operators in C#

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

In C#, the main difference between value types and reference types is in the way of data storage and memory management. 1. The value type directly contains data, usually stored on the stack, such as int, float, bool and struct, with fast access speed and short life cycle; the reference type stores references to the actual data, the object itself is stored on the heap, such as class, string or object, and the reference variables are stored on the stack, relying on garbage collection and cleaning. 2. Copy the actual value when the value type is assigned, and modifying the copy does not affect the original value; copy the reference address when the reference type is assigned, and the two variables point to the same object, and modification will affect each other. 3. The value type cannot be null by default, unless nullable types such as int? are used; the reference type can naturally be nul

CustomAttributes are mechanisms used in C# to attach metadata to code elements. Its core function is to inherit the System.Attribute class and read through reflection at runtime to implement functions such as logging, permission control, etc. Specifically, it includes: 1. CustomAttributes are declarative information, which exists in the form of feature classes, and are often used to mark classes, methods, etc.; 2. When creating, you need to define a class inherited from Attribute, and use AttributeUsage to specify the application target; 3. After application, you can obtain feature information through reflection, such as using Attribute.GetCustomAttribute();

The core of designing immutable objects and data structures in C# is to ensure that the state of the object is not modified after creation, thereby improving thread safety and reducing bugs caused by state changes. 1. Use readonly fields and cooperate with constructor initialization to ensure that the fields are assigned only during construction, as shown in the Person class; 2. Encapsulate the collection type, use immutable collection interfaces such as ReadOnlyCollection or ImmutableList to prevent external modification of internal collections; 3. Use record to simplify the definition of immutable model, and generate read-only attributes and constructors by default, suitable for data modeling; 4. It is recommended to use System.Collections.Imm when creating immutable collection operations.

The key to writing C# code well is maintainability and testability. Reasonably divide responsibilities, follow the single responsibility principle (SRP), and take data access, business logic and request processing by Repository, Service and Controller respectively to improve structural clarity and testing efficiency. Multi-purpose interface and dependency injection (DI) facilitate replacement implementation, extension of functions and simulation testing. Unit testing should isolate external dependencies and use Mock tools to verify logic to ensure fast and stable execution. Standardize naming and splitting small functions to improve readability and maintenance efficiency. Adhering to the principles of clear structure, clear responsibilities and test-friendly can significantly improve development efficiency and code quality.

When processing large amounts of data, C# can be efficient through streaming, parallel asynchronous and appropriate data structures. 1. Use streaming processing to read one by one or in batches, such as StreamReader or EFCore's AsAsyncEnumerable to avoid memory overflow; 2. Use parallel (Parallel.ForEach/PLINQ) and asynchronous (async/await Task.Run) reasonably to control the number of concurrency and pay attention to thread safety; 3. Select efficient data structures (such as Dictionary, HashSet) and serialization libraries (such as System.Text.Json, MessagePack) to reduce search time and serialization overhead.

RecordsinC#areidealforDTOsduetoimmutability,value-basedequality,andreducedboilerplate.1)Immutabilityensuresdataremainsunchangedaftercreation,fittingdatatransportneeds.2)Value-basedequalitysimplifiescomparisonofDTOs.3)Built-inoverridesforEquals(),GetH

The following points should be followed when using LINQ: 1. Priority is given to LINQ when using declarative data operations such as filtering, converting or aggregating data to avoid forced use in scenarios with side effects or performance-critical scenarios; 2. Understand the characteristics of delayed execution, source set modifications may lead to unexpected results, and delays or execution should be selected according to requirements; 3. Pay attention to performance and memory overhead, chain calls may generate intermediate objects, and performance-sensitive codes can be replaced by loops or spans; 4. Keep the query concise and easy to read, and split complex logic into multiple steps to avoid excessive nesting and mixing of multiple operations.