TypeAttributes Enum

Definition

Namespace:

System.Reflection

Assembly:

System.Runtime.dll

Specifies type attributes.

This enumeration supports a bitwise combination of its member values.

public enum class TypeAttributes

[System.Flags]
public enum TypeAttributes

[<System.Flags>]
type TypeAttributes = 

Public Enum TypeAttributes

Inheritance

Object

ValueType

Enum

TypeAttributes

Attributes

FlagsAttribute

Fields

Name	Value	Description
AnsiClass	0	LPTSTR is interpreted as ANSI.
AutoLayout	0	Specifies that class fields are automatically laid out by the common language runtime.
Class	0	Specifies that the type is a class.
NotPublic	0	Specifies that the class is not public.
Public	1	Specifies that the class is public.
NestedPublic	2	Specifies that the class is nested with public visibility.
NestedPrivate	3	Specifies that the class is nested with private visibility.
NestedFamily	4	Specifies that the class is nested with family visibility, and is thus accessible only by methods within its own type and any derived types.
NestedAssembly	5	Specifies that the class is nested with assembly visibility, and is thus accessible only by methods within its assembly.
NestedFamANDAssem	6	Specifies that the class is nested with assembly and family visibility, and is thus accessible only by methods lying in the intersection of its family and assembly.
NestedFamORAssem	7	Specifies that the class is nested with family or assembly visibility, and is thus accessible only by methods lying in the union of its family and assembly.
VisibilityMask	7	Specifies type visibility information.
SequentialLayout	8	Specifies that class fields are laid out sequentially, in the order that the fields were emitted to the metadata.
ExplicitLayout	16	Specifies that class fields are laid out at the specified offsets.
LayoutMask	24	Specifies class layout information.
ClassSemanticsMask	32	Specifies class semantics information; the current class is contextful (else agile).
Interface	32	Specifies that the type is an interface.
Abstract	128	Specifies that the type is abstract.
Sealed	256	Specifies that the class is concrete and cannot be extended.
SpecialName	1024	Specifies that the class is special in a way denoted by the name.
RTSpecialName	2048	Runtime should check name encoding.
Import	4096	Specifies that the class or interface is imported from another module.
Serializable	8192	Specifies that the class can be serialized.
WindowsRuntime	16384	Specifies a Windows Runtime type.
UnicodeClass	65536	LPTSTR is interpreted as UNICODE.
AutoClass	131072	LPTSTR is interpreted automatically.
CustomFormatClass	196608	LPSTR is interpreted by some implementation-specific means, which includes the possibility of throwing a NotSupportedException. Not used in the Microsoft implementation of the .NET Framework.
StringFormatMask	196608	Used to retrieve string information for native interoperability.
HasSecurity	262144	Type has security associate with it.
ReservedMask	264192	Attributes reserved for runtime use.
BeforeFieldInit	1048576	Specifies that calling static methods of the type does not force the system to initialize the type.
CustomFormatMask	12582912	Used to retrieve non-standard encoding information for native interop. The meaning of the values of these 2 bits is unspecified. Not used in the Microsoft implementation of the .NET Framework.

Examples

The following example retrieves the value of the Attributes property for Type objects that represent a number of different types, and then determines whether individual attribute flags have been set.

using System;
using System.Reflection;

internal struct S
{
    public int X;
}

public abstract class Example
{
    protected sealed class NestedClass {}

    public interface INested {}

    public static void Main()
    {
        // Create an array of types.
        Type[] types = { typeof(Example), typeof(NestedClass),
                         typeof(INested), typeof(S) };

        foreach (var t in types) 
        {
           Console.WriteLine("Attributes for type {0}:", t.Name);

           TypeAttributes attr = t.Attributes;

           // To test for visibility attributes, you must use the visibility mask.
           TypeAttributes visibility = attr & TypeAttributes.VisibilityMask;
           switch (visibility)
           {
               case TypeAttributes.NotPublic:
                   Console.WriteLine("   ...is not public");
                   break;
               case TypeAttributes.Public:
                   Console.WriteLine("   ...is public");
                   break;
               case TypeAttributes.NestedPublic:
                   Console.WriteLine("   ...is nested and public");
                   break;
               case TypeAttributes.NestedPrivate:
                   Console.WriteLine("   ...is nested and private");
                   break;
               case TypeAttributes.NestedFamANDAssem:
                   Console.WriteLine("   ...is nested, and inheritable only within the assembly" +
                      "\n         (cannot be declared in C#)");
                   break;
               case TypeAttributes.NestedAssembly:
                   Console.WriteLine("   ...is nested and internal");
                   break;
               case TypeAttributes.NestedFamily:
                   Console.WriteLine("   ...is nested and protected");
                   break;
               case TypeAttributes.NestedFamORAssem:
                   Console.WriteLine("   ...is nested and protected internal");
                   break;
           }

           // Use the layout mask to test for layout attributes.
           TypeAttributes layout = attr & TypeAttributes.LayoutMask;
           switch (layout)
           {
               case TypeAttributes.AutoLayout:
                   Console.WriteLine("   ...is AutoLayout");
                   break;
               case TypeAttributes.SequentialLayout:
                   Console.WriteLine("   ...is SequentialLayout");
                   break;
               case TypeAttributes.ExplicitLayout:
                   Console.WriteLine("   ...is ExplicitLayout");
                   break;
           }

           // Use the class semantics mask to test for class semantics attributes.
           TypeAttributes classSemantics = attr & TypeAttributes.ClassSemanticsMask;
           switch (classSemantics)
           {
               case TypeAttributes.Class:
                   if (t.IsValueType)
                   {
                       Console.WriteLine("   ...is a value type");
                   }
                   else
                   {
                       Console.WriteLine("   ...is a class");
                   }
                   break;
               case TypeAttributes.Interface:
                   Console.WriteLine("   ...is an interface");
                   break;
           }

           if ((attr & TypeAttributes.Abstract) != 0)
           {
               Console.WriteLine("   ...is abstract");
           }

           if ((attr & TypeAttributes.Sealed) != 0)
           {
               Console.WriteLine("   ...is sealed");
           }
           
           Console.WriteLine();
       }
    }
}
// The example displays the following output:
// Attributes for type Example:
//    ...is public
//    ...is AutoLayout
//    ...is a class
//    ...is abstract

// Attributes for type NestedClass:
//    ...is nested and protected
//    ...is AutoLayout
//    ...is a class
//    ...is sealed

// Attributes for type INested:
//    ...is nested and public
//    ...is AutoLayout
//    ...is an interface
//    ...is abstract

// Attributes for type S:
//    ...is not public
//    ...is SequentialLayout
//    ...is a value type
//    ...is sealed

Imports System.Reflection

Friend Structure S
    Public X As Integer
End Structure

Public MustInherit Class Example
    Protected NotInheritable Class NestedClass
    End Class

    Public Interface INested
    End Interface

    Public Shared Sub Main()
        ' Create an array of types.
        Dim types() As Type = { GetType(Example), GetType(NestedClass),
                                GetType(INested), GetType(S) }

        For Each t In types
           Console.WriteLine("Attributes for type {0}:", t.Name)

           Dim attr As TypeAttributes = t.Attributes

           ' Use the visibility mask to test for visibility attributes.
           Dim visibility As TypeAttributes = attr And TypeAttributes.VisibilityMask
           Select Case visibility
               Case TypeAttributes.NotPublic:
                   Console.WriteLine("   ...is not Public")
               Case TypeAttributes.Public:
                   Console.WriteLine("   ...is Public")
               Case TypeAttributes.NestedPublic:
                   Console.WriteLine("   ...is nested and Public")
               Case TypeAttributes.NestedPrivate:
                   Console.WriteLine("   ...is nested and Private")
               Case TypeAttributes.NestedFamANDAssem:
                   Console.WriteLine("   ...is nested, and inheritable only within the assembly" & _
                      vbLf & "         (cannot be declared in Visual Basic)")
               Case TypeAttributes.NestedAssembly:
                   Console.WriteLine("   ...is nested and Friend")
               Case TypeAttributes.NestedFamily:
                   Console.WriteLine("   ...is nested and Protected")
               Case TypeAttributes.NestedFamORAssem:
                   Console.WriteLine("   ...is nested and Protected Friend")
           End Select

           ' Use the layout mask to test for layout attributes.
           Dim layout As TypeAttributes = attr And TypeAttributes.LayoutMask
           Select Case layout
               Case TypeAttributes.AutoLayout:
                   Console.WriteLine("   ...is AutoLayout")
               Case TypeAttributes.SequentialLayout:
                   Console.WriteLine("   ...is SequentialLayout")
               Case TypeAttributes.ExplicitLayout:
                   Console.WriteLine("   ...is ExplicitLayout")
           End Select

           ' Use the class semantics mask to test for class semantics attributes.
           Dim classSemantics As TypeAttributes = attr And TypeAttributes.ClassSemanticsMask
           Select Case classSemantics
               Case TypeAttributes.Class:
                   If t.IsValueType Then
                       Console.WriteLine("   ...is a value type")
                   Else
                       Console.WriteLine("   ...is a class")
                   End If
               Case TypeAttributes.Interface:
                   Console.WriteLine("   ...is an interface")
           End Select

           If 0 <> (attr And TypeAttributes.Abstract) Then _
               Console.WriteLine("   ...is MustInherit")

           If 0 <> (attr And TypeAttributes.Sealed) Then _
               Console.WriteLine("   ...is NotInheritable")
           Console.WriteLine()
       Next
    End Sub
End Class
' The example displays the following output:
'       Attributes for type Example:
'          ...is Public
'          ...is AutoLayout
'          ...is a class
'          ...is MustInherit
'
'       Attributes for type NestedClass:
'          ...is nested and Protected
'          ...is AutoLayout
'          ...is a class
'          ...is NotInheritable
'
'       Attributes for type INested:
'          ...is nested and Public
'          ...is AutoLayout
'          ...is an interface
'          ...is MustInherit
'
'       Attributes for type S:
'          ...is not Public
'          ...is SequentialLayout
'          ...is a value type
'          ...is NotInheritable

Remarks

Some of the members of the TypeAttributes enumeration are masks that represent a set of mutually exclusive attributes. For example, the VisibilityMask member includes the NotPublic, Public, NestedPublic, NestedPrivate, NestedFamily, NestedAssembly, NestedFamANDAssem, and NestedFamORAssem members. Because each attribute set includes a member whose underlying value is zero, you should first And the value of the mask with the specific System.Reflection.TypeAttributes value retrieved from a property such as Type.Attributes. The following table lists the masks and the individual members that they include:

Mask	Includes
VisibilityMask	NotPublic Public NestedPublic NestedPrivate NestedFamily NestedAssembly NestedFamANDAssem NestedFamORAssem
LayoutMask	AutoLayout SequentialLayout ExplicitLayout
ClassSemanticsMask	Class Interface
StringFormatMask	AnsiClass UnicodeClass AutoClass CustomFormatClass
CustomFormatMask	No members.

The members of this enumerator class match the CorTypeAttr enumerator as defined in the corhdr.h file.