Need To Master In Reflections and Attributes... help

Question

I need some exercise to master in reflection, late and early binding and attributes.

Rajanikant Hawaldar · Answer

Hi Dear, Reflection .NET Framework's Reflection API allows you to fetch Type (Assembly) information at runtime or programmatically. We can also implement late binding using .NET Reflection. At runtime, Reflection uses the PE file to read the metadata about an assembly. Reflection enables you to use code that was not available at compile time. .NET Reflection allows application to collect information about itself and also manipulate on itself. It can be used effectively to find all the types in an assembly and/or dynamically invoke methods in an assembly. This includes information about the type, properties, methods and events of an object. With reflection, we can dynamically create an instance of a type, bind the type to an existing object, or get the type from an existing object and invoke its methods or access its fields and properties. We can also access attributes using Reflection. In short, Reflection can be very useful if you don't know much about an assembly. https://www.c-sharpcorner.com/UploadFile/keesari_anjaiah/reflection-in-net/ https://www.youtube.com/watch?v=y8-uq6Ur7Dc https://www.youtube.com/watch?v=vHHd3GNOuXU Late & Early Binding in C# Everything is early bound in C# unless you go through the Reflection interface. Early bound just means the target method is found at compile time, and code is created that will call this. Whether its virtual or not (meaning there's an extra step to find it at call time is irrelevant). If the method doesn't exist the compiler will fail to compile the code. Late bound means the target method is looked up at run time. Often the textual name of the method is used to look it up. If the method isn't there, bang. The program will crash or go into some exception handling scheme at run time. Most script languages use late binding, and compiled languages use early binding. C# (prior to version 4) doesn't late bind; they can however use the reflection API to do it. That API compiles to code that looks up function names by digging through assemblies at run time. VB can late bind if Option Strict is turned off. Binding usually has an effect on performance. Because late binding requires lookups at runtime, it is usually means method calls are slower than early bound method calls. For a normal function, the compiler can work out the numeric location of it in memory. Then it when the function is called it can generate an instruction to call the function at this address. For an object that has any virtual methods, the compiler will generate a v-table. This is essentially an array that contains the addresses of the virtual methods. Every object that has a virtual method will contain a hidden member generated by the compiler that is the address of the v-table. When a virtual function is called, the compiler will work out what the position is of the appropriate method in the v-table. It will then generate code to look in the objects v-table and call the virtual method at this position. So, there is a lookup that occurs for the virtual function. This is heavily optimized so it will happen very quickly at run-time. Early bound The compiler can work out where the called function will be at compile time. The compiler can guarantee early (before any of the programs code runs) that the function will exist and be callable at runtime. The compiler guarantees that the function takes the right number of arguments and that they are of the correct type. It also checks that the return value is of the correct type. Late-binding The lookup will take longer because its not a simple offset calculation, there are usually text comparisons to be made. The target function may not exist. The target function may not accept the arguments passed to it, and may have a return value of the wrong type. With some implementations, the target method can actually change at run-time. So, the lookup may execute a different function. I think this happens in the Ruby language, you can define a new method on an object while the program is running. Late-binding allows function calls to start calling a new override for a method instead of calling the existing base method. https://stackoverflow.com/questions/484214/early-and-late-binding https://www.c-sharpcorner.com/uploadfile/babu_2082/early-binding-vs-late-binding/ https://www.geeksforgeeks.org/early-and-late-binding-in-c-sharp/ Attributes: Attributes are like adjectives, which are used for metadata annotation that can be applied to a given type, assembly, module, method and so on. The .NET framework stipulates two types of attribute implementations, which are Predefined Attributes and Custom Attributes. https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/attributes/ https://www.infoworld.com/article/3006630/how-to-work-with-attributes-in-c.html https://www.c-sharpcorner.com/UploadFile/84c85b/using-attributes-with-C-Sharp-net/ Thanks

Rajanikant Hawaldar · Answer

Your welcome dear

Bidzina Goginashvili · Answer

thank you so much Rajanikant Hawaldar