Generic Collections

Question

Why we are saying Generic Colections are strongly Typed objects? Please Any explain me the reason behind that i want some one to chat with me...

Jignesh Kumar · Answer

Hi Melbin, You are right, it allows you because you have created generic list with dynamic type and dynamic will allow you to assign any types of data. Here Typesafe in meaning like IList int > intList= new List int >() ; // Only allows integer values IList string > strList = new List string >(); // only allows string values IList studentList = new List (); // only allows type of student model In your case you have created List of Dynamic object so it will allow all datatypes. List lstcheck= new List (); Thanks.

Madan Shekar · Answer

C# (and C++ and many other languages) is strongly typed because the compiler will detect and flag these errors at compilation time. No. It means that 1 and "1" (or any other number and string for that matter) are different values that cannot be casually interchanged in expressions

Melbin · Answer

Ok ,Generic collections are type dependent ,I say its not type dependent For Example : List lstcheck=new Lis (); Dynamic type is used ... Here i can add the items like a non generic List lst.Add("Melbin"); lst.Add(1); lst.Add('c'); Thanks Melbin.

Laxmidhar Sahoo · Answer

Thanks Jignesh

Jignesh Kumar · Answer

Hi Melbie, I will provide one example for generic is type safe (strongly type) and non generic collection is not type safe. Below exmple of non-generic : var nonGenericList = new ArrayList(); nonGenericList.Add(1); nonGenericList.Add(2); nonGenericList.Add("3"); for (int i = 0; i { int integer = (int)nonGenericList[i]; Console.WriteLine(integer); } So while retrieving you have to check type and non-generic will allow storing any datatype. Generic collection: example: List intList = new List(); List stringList = new List(); Please have a look at below screencast it will check your type at compile time only and it will not allow you to put other type than its type. Hope it will help you. Thank you..

Melbin · Answer

Thank you jingnesh Kumar I think we can use this dynamic type List as a non generic collection Like ArrayList ?

Laxmidhar Sahoo · Answer

1-May get information on the types used in a generic data type at run-time by means of reflection. 2-Typically, you create generic classes by starting with an existing concrete class , and changing types into type parameters one at a time until you reach the optimal balance of generalization and usability. When creating your own generic classes, important considerations 3-Generics introduced in C# 2.0. Generics allow you to define a class with placeholders for the type of its fields, methods, parameters, etc. Generics replace these placeholders with some specific type at compile time. 4-A generic class can be defined using angle brackets . 5-In this example, the letter T denotes a type that is only known based on the calling location. And: The program can act upon the instance of T like it is a real type, but it is not. 6-the Base library is using System.Collections.Generic; Bellow is the Example using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace generic { class Program { static void Main( string [] args) { // Use the generic type Test with an int type parameter. GenericTest int > test1 = new GenericTest int >(5); // Call the Write method. test1.Write(); // Use the generic type Test with a string type parameter. GenericTest string > test2 = new GenericTest string >( "cat" ); test2.Write(); } } class GenericTest { T _value; public GenericTest(T t) { // The field has the same type as the parameter. this ._value = t; } public void Write() { Console.WriteLine( this ._value); } } }