Dispose methods should call base class dispose

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Microsoft Visual Studio 2005/.NET Framework 2.0

Other versions are also available for the following:

Microsoft Visual Studio 2010/.NET Framework 4.0

Visual Studio Team System

Dispose methods should call base class dispose

TypeName	DisposeMethodsShouldCallBaseClassDispose
CheckId	CA2215
Category	Microsoft.Usage
Breaking Change	NonBreaking

Cause

A type that implements System.IDisposable inherits from a type that also implements IDisposable. The Dispose method of the inheriting type does not call the Dispose method of the parent type.

Rule Description

If a type inherits from a disposable type, it must call the Dispose method of the base type from within its own Dispose method.

How to Fix Violations

To fix a violation of this rule, call base.Dispose in your Dispose method.

When to Exclude Warnings

It is safe to exclude a warning from this rule if the call to base.Dispose occurs at a deeper calling level than the rule checks.

Example

The following example shows a type TypeA that implements IDisposable.

using System;  

namespace UsageLibrary
{
    public class  TypeA :IDisposable
    {
     
        protected virtual void Dispose(bool disposing) 
        {
            if (disposing) 
            {
                // Dispose managed resources
            }

            // Free native resources
        }

        public void Dispose()
        {

                Dispose(true);

                GC.SuppressFinalize(this);

        }

        // Disposable types implement a finalizer.
        ~TypeA()
        {
            Dispose(false);
        }
    }
}

The following example shows a type TypeB that inherits from type TypeA and correctly calls its Dispose method.

Visual Basic

Imports System

Namespace UsageLibrary

    Public Class TypeB
        Inherits TypeA

        Friend Overrides Sub Dispose(ByVal disposing As Boolean)
            Try
                Dispose(False)
            Finally
                MyBase.Finalize()
            End Try
        End Sub 'Dispose
    End Class 'TypeB

End Namespace

Reference

Implementing Finalize and Dispose to Clean Up Unmanaged Resources
System.IDisposable

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Annotations

Correct VB Implementation

Peter Ritchie | Edit | Show History

As provided, the VB code for TypeB will not compile based on the C# code for TypeA; Friend Dispose is a different access level from TypeA.Dispose (which is Protected, not Friend). Plus, TypeB.Dispose actually causes infinite recursion and eventually StackOverflowException. Following is correct code:

 Friend Class TypeB
  Inherits TypeA

  Protected Overrides Sub Dispose(ByVal disposing As Boolean)
   Try
    If disposing Then
     ' dispose of managed resources
    End If
    ' free native resources.
   Finally
    MyBase.Dispose(disposing)
   End Try
  End Sub 'Dispose
 End Class 'TypeB