Destroy an object in C#

Question

How to destroy an object in finally block.

For example

 Public void fnName()
 {
    ClassName obj = new ClassName();
    try {

    }
    catch() {

    }
    finally {
        // destroy obj here
    }
 }

If the Class of the object implements IDisposable, you can call obj.Dispose(). — WeSt, Sep 10 '14 at 12:06
@FarhadJabiyev obj = null is pretty useless if the variable obj is defined within a function scope (since the reference exists on the stack). Are you trying to clean up resources? — Bas, Sep 10 '14 at 12:06
well, since it's a local variable, you don't really have to do `obj=null;`. If it's not referenced anywhere else, the garbage collector will take care of it. — vesan, Sep 10 '14 at 12:07
As vesan says, let the garbage collector take of it. Unless your class implements `IDisposable` don't worry about it — Sayse, Sep 10 '14 at 12:08
In order for anyone to answer your question well, you need to explain why you feel that it is important that some form of finalization occurs at a programmer specified point in time. — David Heffernan, Sep 10 '14 at 12:24

score 34 · Accepted Answer · edited Oct 10 '14 at 04:22

Do nothing. Your reference (obj) will go out of scope. Then the Garbage Collector will come along and destroy your object.

If there are (unmanaged) resources that need to be destroyed immediately, then implement the IDisposable interface and call Dispose in the finalize block. Or better, use the using statement.

EDIT

As suggested in the comments, when your ClassName implements IDisposable, you could either do:

ClassName obj = null;
try{
   obj = new ClassName();
   //do stuff
}
finally{
   if (obj != null) { obj.Dispose(); }
}

Or, with a using statement:

using (var obj = new ClassName())
{
     // do stuff
}

Showing his code, but rewritten to use `using` might be helpful. — hatchet - done with SOverflow, Sep 10 '14 at 12:09

score 8 · Answer 2 · edited Apr 08 '18 at 18:04

First of all, there is nothing called Destroy in C# language. Instead, we call Dispose.

The Garbage Collector automatically executes cleanup procedures when an object goes out of scope but for the unmanaged resources like sockets, db calls etc and you need to Dispose the object as shown below:

Public void fnName()
{
    ClassName obj=new ClassName();
    try
    {

    }
    catch()
    {

    }
    finally
    {
       obj.Dispose();
    }
}

...and implement Dispose functionality in your class as shown below:

      /// <summary>
      /// Dispose all used resources.
      /// </summary>
      public void Dispose()
      {
          this.Dispose(true);
          GC.SuppressFinalize(this);
      }

        /// <summary>
        /// Dispose all used resources.
        /// </summary>
        /// <param name="disposing">Indicates the source call to dispose.</param>
        private void Dispose(bool disposing)
        {
            if (this.disposed)
            {
                return;
            }

            if (disposing)
            {
                ////Number of instance you want to dispose
            }
        }

Another way to hinder the lifespan of an object is to write your code inside a using block as shown below:

using(var obj = new ClassName())
{
}

For more details for using check it here

I'm not the one who downvoted but I have to ask this......can you justify why you need to call GC.SuppressFinalize(this);? — Mo Patel, Sep 10 '14 at 12:09
"C#" cannot do any cleanup; the .NET Framework and the Garbage Collector does. "C#" is just a programming language. — Uwe Keim, Sep 10 '14 at 12:13

Destroy an object in C#

2 Answers2