What is reflection in c#?

Reflection refers to providing objects that encapsulate assemblies, modules and types. You can dynamically create instances of types and bind types to existing objects through reflection. It is often used to check and instantiate objects in assemblies. types and building new types at runtime, etc.

The main content of this article is to introduce to you in detail what reflection is in C#. It has a certain reference function and I hope it will be helpful to everyone

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What is reflection

Reflection refers to providing objects (Type types) that encapsulate assemblies, modules and types. You can use reflection to dynamically create instances of a type, bind the type to an existing object, or obtain the type from an existing object and call its methods or access its fields and properties. If attributes are used in your code, they can be accessed using reflection.

Reflection usage scenarios

Features that require access to program metadata.

Check and instantiate types in assemblies.

Construct new types at runtime.

Use classes in System.Reflection.Emit.

Perform late binding and access methods of types created at runtime

How to use reflection to obtain types

There are two ways to obtain type information , one is to get the instance object, and the other is to get the instance object through the Type.GetType and Assembly.GetType methods

Get the instance object

In this method, you only get This instance object may be obtained as a reference to an object or an interface reference, but its exact type is not known. If you need to know more, you can call System.Object The method GetType declared above is used to obtain the type object of the instance object. For example, in a certain method, I need to determine whether the parameter passed in implements a certain interface. If it does, call a method of the interface:

…
public  void  Process(  object  processObj  ){
Type  t  =  processsObj.GetType();
if(  t.GetInterface(“ITest”)  !=null  )                    
…}…

Type.GetType and Assembly.GetType methods

Another way to get the type is through the Type.GetType and Assembly.GetType methods, such as:

Type  t  =  Type.GetType(“System.String”);

It should be noted that to find a class, you must specify the assembly in which it is located, or call GetType on the obtained Assembly instance. The type in this assembly can only write the type name. Another exception is mscorlib.dll. The type declared in this assembly can also omit the assembly name (when the .Net assembly is compiled, it is quoted by default. mscorlib.dll, unless explicitly specified not to reference it during compilation), for example:

System.String is declared in mscorlib.dll, above The Type t = Type.GetType("System.String") is correct.

System.Data.DataTable is declared in System.Data.dll, then Type.GetType("System.Data.DataTable") can only get a null reference.
So

Type t = Type.GetType("System.Data.DataTable,System.Data,Version=1.0.3300.0,  
Culture=neutral,  PublicKeyToken=b77a5c561934e089");

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