Avoid unsealed attributes
TypeName |
AvoidUnsealedAttributes |
CheckId |
CA1813 |
Category |
Microsoft.Performance |
Breaking Change |
Breaking |
Cause
A public type inherits from System.Attribute, is not abstract, and is not sealed (NotInheritable in Visual Basic).
Rule Description
The .NET Framework class library provides methods for retrieving custom attributes. By default, these methods search the attribute inheritance hierarchy; for example Attribute.GetCustomAttribute searches for the specified attribute type, or any attribute type that extends the specified attribute type. Sealing the attribute eliminates the search through the inheritance hierarchy, and can improve performance.
How to Fix Violations
To fix a violation of this rule, seal the attribute type or make it abstract.
When to Suppress Warnings
It is safe to suppress a warning from this rule. You should do this only if you are defining an attribute hierarchy and cannot seal the attribute or make it abstract.
Example
The following example shows a custom attribute that satisfies this rule.
Imports System
Namespace PerformanceLibrary
' Satisfies rule: AvoidUnsealedAttributes.
<AttributeUsage(AttributeTargets.Class Or AttributeTargets.Struct)> _
NotInheritable Public Class DeveloperAttribute
Inherits Attribute
Private nameValue As String
Public Sub New(name As String)
nameValue = name
End Sub
Public ReadOnly Property Name() As String
Get
Return nameValue
End Get
End Property
End Class
End Namespace
using System;
namespace PerformanceLibrary
{
// Satisfies rule: AvoidUnsealedAttributes.
[AttributeUsage(AttributeTargets.Class|AttributeTargets.Struct)]
public sealed class DeveloperAttribute: Attribute
{
private string nameValue;
public DeveloperAttribute(string name)
{
nameValue = name;
}
public string Name
{
get
{
return nameValue;
}
}
}
}
Related Rules
Define accessors for attribute arguments
Mark attributes with AttributeUsageAttribute