Background

A very quick post on a very easy to address C# error.

 

Error

Image

Text

‘Person’:type used in a using statement must be implicitly convertible to ‘System.IDisposable’.

 

Scenario #1

A  very simple scenario.

We have a class called Person.

The class has a simple property called name.

We initialize the class and set its name property.

We print out that name by invoking Console.WriteLine.

Code

using System;

public class Person 
{

    public string name { get; set; }
    
    
}


public class Program
{
    
    public static void Main()
    {
        sayName();
        
        sayNameCleanupExplicit();
        
        
    }
    
    private static void sayName()
    {

        Person p1 = new Person();
		
        p1.name = "Jay";
        
        Console.WriteLine("My name is " + p1.name);
        
    }
    
    private static void sayNameCleanupExplicit()
    {
	
        Person p2 = new Person();
	
        p2.name = "Brent";
        
        Console.WriteLine("My name is " + p2.name);
        
        p2 = null;
    }
    

}

 

Explanation

We have two methods above:-

1. sayName
2. sayNameCleanupExplicit

The only difference is that sayNameCleanupExplicit sets the object instance p2 to null.

 

Scenario #2

In our second scenario, we will like to automatically handle object deallocation.

Code

private static void sayNameCleanupImplicit()
{
   using
   (
      Person objPersonDisp = new Person()
   )
   {

      objPersonDisp.name = "Tim";
      
      Console.WriteLine
      (
          "My name is " + objPersonDisp.name
      );

   }
        
}

Error

Once we add the “using statement“, we get the error we aforementioned.

And, the error reads:-

Image

Textual

error CS1674: 'Person': type used in a using statement must be implicitly convertible to 'System.IDisposable'

Error Signature

Depending on the version of the compiler you are using, the error’s signature may vary.

Here are some variants:-

1. Microsoft (R) Visual C# Compiler version 4.8.4084.0
   for C# 5
   • Syntax
     • error CS1674: ‘<type>’: type used in a using statement must be implicitly convertible to ‘System.IDisposable’
   • Example
     • person.revised.cs(56,9): error CS1674: ‘Person’: type used in a using statement must be implicitly convertible to ‘System.IDisposable’

 

Remediation

To remediate is simple.

It involves:-

1. Implement the IDisposable interface
   • Override the Dispose method

Code

public class Person : IDisposable
{

    public string name { get; set; }

    void IDisposable.Dispose()
    {

    }

}

 

Summary

The disposition of the object’s instance takes slightly different tracks.

Original Class

1. sayNameCleanupExplicit
   • Disposition initiates upon setting the object’s instance to null
2. sayName
   • Disposition initiates upon exiting the method

Revised Class

1. sayNameCleanupImplicit
   • Disposition initiates upon closure of the using statement

References

1. Microsoft
   • C#
     • using statement (C# Reference)
       Link