using constructor

narasiman rao

9y998Visual Basic .NET

how to restrict class from creating object using constructor

3 Replies

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Tapan Patel9y ago
if not misunderstood, you are looking at singleton design pattern where you need only one object throughout the application. below could be one of the possible implementations if that's what you are looking for (also not that, this is not thread-safe.) Having private constructor will not allow other classes to create an object.
class TestPvtConstructior
       {
           private static TestPvtConstructior _pvtmemeber;
           private TestPvtConstructior()
           {

           }
           public static TestPvtConstructior GetInstance()
           {
               if (_pvtmemeber==null)
               {
                   _pvtmemeber = new TestPvtConstructior();
               }
               return _pvtmemeber;
           }
       }
And in your main method you can get only one object by doing:
var instance = TestPvtConstructior.GetInstance();
0
Ankit Sahu9y ago
By using Private constructor restrict class object to create Because it inaccessible due to it protection level.
Private access is the least permissive access level.

Private members are accessible only within the body of the class or the struct in which they are declared.
using System;

namespace ConsoleApplication1

{

    public class UsersData

    {

        private UsersData() { }

    }

    class Program

    {

        static void Main(string[] args)

        {

            UsersData users = new UsersData();

            Console.ReadKey();

        }

    }

}
Compile time Error :-

If you define public constructor It’s accessible everywhere in your project .
using System;

namespace ConsoleApplication1

{

    public class UsersData

    {

        public UsersData() { }

    }

    class Program

    {

        static void Main(string[] args)

        {

            UsersData users = new UsersData();

            Console.ReadKey();

        }

    }

}

Build Successfully.
0
Ravi Patel9y ago
Hi,

If we declare a private constructor then you can not create object outside of this class but you can create object in same class where you created a private constructor. there is no other way to restrict the object creation by using constructor.

alternate way make a class as
Abstract
Static Class
0