use of using statement in c sharp

USING-The .Net Framework provides resource management for managed objects through the garbage collector - You do not have to explicitly allocate and release memory for managed objects. Clean-up operations for any unmanaged resources should be performed in the destructor in C#.

To allow the programmer to explicitly perform these clean-up activities, objects can provide a Dispose method that can be invoked when the object is no longer needed. The using statement in C# defines a boundary for the object outside of which, the object is automatically destroyed. The using statement is exited when the end of the "using" statement block or the execution exits the "using" statement block indirectly, for example - an exception is thrown.

There is 2 use of using statement. 1:- Importing namespace example:using System; 2:- dispose the object using(SqlConnection oConnection=new SqlConnection()) { oConnection.Open(); } if you won't close the connection it will close the connection automatically once SqlConnection has been executed completing.

The "using" statement allows you to specify multiple resources in a single statement. The object could also be created outside the "using" statement. The objects specified within the using block must implement the IDisposable interface. The framework invokes the Dispose method of objects specified within the "using" statement when the block is exited.

Note:-

The UsingProgram class is not a part of the .NET Framework and is only used in the example for demonstration. The UsingProgram class needs to be released explicitly and implements the IDisposable interface.

Example 1

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.Mvc;

namespace Test

{

    class UsingProgram:IDisposable

    {

        public void Dispose()

        {

            throw new NotImplementedException();

        }

        public int ShowSum(int x, int y)

        {

            return x + y;

        }

       

    }

    class Program

    {

      

        static void Main(string[] args)

        {

            using (UsingProgram obj = new UsingProgram())

            {

                obj.ShowSum(2, 3);//herer you use this

            }//here it is release by using statement

        }

    }

}

Example 2

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.Mvc;

namespace Test

{

    class UsingProgram:IDisposable

    {

        public void Dispose()

        {

            throw new NotImplementedException();

        }

        public int ShowSum(int x, int y)

        {

            return x + y;

        }

       

    }

    class Program

    {

      

        static void Main(string[] args)

        {

            UsingProgram obj = new UsingProgram();

            using (obj)

            {

                obj.ShowSum(2, 3);//herer you use this

            }//here it is release by using statement

        }

    }

}

Note that the using Directive in C# is different from the using statement. The "using" Directive is used to provide an alias for a namespace.