CA2216: Disposable types should declare finalizer
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The latest version of this topic can be found at CA2216: Disposable types should declare finalizer.
TypeName|DisposableTypesShouldDeclareFinalizer|
|CheckId|CA2216|
|Category|Microsoft.Usage|
|Breaking Change|Non Breaking|
A type that implements System.IDisposable, and has fields that suggest the use of unmanaged resources, does not implement a finalizer as described by Object.Finalize.
A violation of this rule is reported if the disposable type contains fields of the following types:
To fix a violation of this rule, implement a finalizer that calls your Dispose method.
It is safe to suppress a warning from this rule if the type does not implement IDisposable for the purpose of releasing unmanaged resources.
The following example shows a type that violates this rule.
using System; using System.Runtime.InteropServices; namespace UsageLibrary { public class DisposeMissingFinalize :IDisposable { private bool disposed = false; private IntPtr unmanagedResource; [DllImport("native.dll")] private static extern IntPtr AllocateUnmanagedResource(); [DllImport("native.dll")] private static extern void FreeUnmanagedResource(IntPtr p); DisposeMissingFinalize() { unmanagedResource = AllocateUnmanagedResource(); } protected virtual void Dispose(bool disposing) { if (!disposed) { // Dispose of resources held by this instance. FreeUnmanagedResource(unmanagedResource); disposed = true; // Suppress finalization of this disposed instance. if (disposing) { GC.SuppressFinalize(this); } } } public void Dispose() { Dispose(true); } // Disposable types with unmanaged resources implement a finalizer. // Uncomment the following code to satisfy rule: // DisposableTypesShouldDeclareFinalizer // ~TypeA() // { // Dispose(false); // } } }
CA2115: Call GC.KeepAlive when using native resources
CA1816: Call GC.SuppressFinalize correctly
CA1049: Types that own native resources should be disposable
System.IDisposable
System.IntPtr
System.Runtime.InteropServices.HandleRef
System.UIntPtr
Object.Finalize
Dispose Pattern