CA1047: Do not declare protected members in sealed types
Note
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Item | Value |
---|---|
TypeName | DoNotDeclareProtectedMembersInSealedTypes |
CheckId | CA1047 |
Category | Microsoft.Design |
Breaking Change | Non-breaking |
Cause
A public type is sealed
(NotInheritable
in Visual basic) and declares a protected member or a protected nested type. This rule does not report violations for Finalize methods, which must follow this pattern.
Rule Description
Types declare protected members so that inheriting types can access or override the member. By definition, you cannot inherit from a sealed type, which means that protected methods on sealed types cannot be called.
The C# compiler issues a warning for this error.
How to Fix Violations
To fix a violation of this rule, change the access level of the member to private, or make the type inheritable.
When to Suppress Warnings
Do not suppress a warning from this rule. Leaving the type in its current state can cause maintenance issues and does not provide any benefits.
Example
The following example shows a type that violates this rule.
using System;
namespace DesignLibrary
{
public sealed class SealedClass
{
protected void ProtectedMethod(){}
}
}
Imports System
Namespace DesignLibrary
Public NotInheritable Class BadSealedType
Protected Sub MyMethod
End Sub
End Class
End Namespace