CA1048: Do not declare virtual members in sealed types
| Item | Value |
|---|---|
| RuleId | CA1048 |
| Category | Microsoft.Design |
| Breaking change | Breaking |
Cause
A public type is sealed and declares a method that is both virtual (Overridable in Visual Basic) and not final. This rule does not report violations for delegate types, which must follow this pattern.
Note
This rule has been deprecated. For more information, see Deprecated rules.
Rule description
Types declare methods as virtual so that inheriting types can override the implementation of the virtual method. By definition, you cannot inherit from a sealed type, making a virtual method on a sealed type meaningless.
The Visual Basic and C# compilers do not allow types to violate this rule.
How to fix violations
To fix a violation of this rule, make the method non-virtual 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.