TypeAttributes Enumeration

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Specifies type attributes.

This enumeration has a FlagsAttribute attribute that allows a bitwise combination of its member values.

Namespace: System.Reflection
Assembly: mscorlib (in mscorlib.dll)

Syntax

<FlagsAttribute> _
Public Enumeration TypeAttributes
[FlagsAttribute]
public enum TypeAttributes

Members

Member name Description
Abstract Specifies that the type is abstract.
AnsiClass LPTSTR is interpreted as ANSI.
AutoClass LPTSTR is interpreted automatically.
AutoLayout Specifies that class fields are automatically laid out by the common language runtime.
BeforeFieldInit Specifies that calling static methods of the type does not force the system to initialize the type.
Class Specifies that the type is a class.
ClassSemanticsMask Specifies class semantics information; the current class is contextful (else agile).
CustomFormatClass 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.
CustomFormatMask 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.
ExplicitLayout Specifies that class fields are laid out at the specified offsets.
HasSecurity Type has security associate with it.
Import Specifies that the class or interface is imported from another module.
Interface Specifies that the type is an interface.
LayoutMask Specifies class layout information.
NestedAssembly Specifies that the class is nested with assembly visibility, and is thus accessible only by methods within its assembly.
NestedFamANDAssem 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.
NestedFamily Specifies that the class is nested with family visibility, and is thus accessible only by methods within its own type and any subtypes.
NestedFamORAssem 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.
NestedPrivate Specifies that the class is nested with private visibility.
NestedPublic Specifies that the class is nested with public visibility.
NotPublic Specifies that the class is not public.
Public Specifies that the class is public.
ReservedMask Attributes reserved for runtime use.
RTSpecialName Runtime should check name encoding.
Sealed Specifies that the class is concrete and cannot be extended.
SequentialLayout Specifies that class fields are laid out sequentially, in the order that the fields were emitted to the metadata.
Serializable Specifies that the class can be serialized.
SpecialName Specifies that the class is special in a way denoted by the name.
StringFormatMask Used to retrieve string information for native interoperability.
UnicodeClass LPTSTR is interpreted as UNICODE.
VisibilityMask Specifies type visibility information.
WindowsRuntime Specifies a Windows Runtime type.

Remarks

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

Examples

The following example shows the use of type attributes. The fact that there is a member in each of several groupings that has the value zero means that you must use masks before testing for those members.

For most purposes, properties like Type..::.IsClass, Type..::.IsAutoLayout, and Type..::.IsSpecialName are easier to use than type attributes.

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

    Private Shared outputBlock As System.Windows.Controls.TextBlock

    Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)

        Example.outputBlock = outputBlock

        DisplayAttributes(GetType(Example))
        DisplayAttributes(GetType(NestedClass))
        DisplayAttributes(GetType(INested))
        DisplayAttributes(GetType(S))

    End Sub

    Private Shared Sub DisplayAttributes(ByVal t As Type)

        outputBlock.Text &= "Attributes for type " & t.Name & ":" & vbLf

        Dim attr As TypeAttributes = t.Attributes

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

        Dim layout As TypeAttributes = attr And TypeAttributes.LayoutMask
        Select Case layout
            Case TypeAttributes.AutoLayout:
                outputBlock.Text &= "   ...is AutoLayout" & vbLf
            Case TypeAttributes.SequentialLayout:
                outputBlock.Text &= "   ...is SequentialLayout" & vbLf
            Case TypeAttributes.ExplicitLayout:
                outputBlock.Text &= "   ...is ExplicitLayout" & vbLf
        End Select

        Dim classSemantics As TypeAttributes = attr And TypeAttributes.ClassSemanticsMask
        Select Case classSemantics
            Case TypeAttributes.Class:
                If t.IsValueType Then
                    outputBlock.Text &= "   ...is a value type" & vbLf
                Else
                    outputBlock.Text &= "   ...is a class" & vbLf
                End If
            Case TypeAttributes.Interface:
                outputBlock.Text &= "   ...is an interface" & vbLf
        End Select

        If 0 <> (attr And TypeAttributes.Abstract) Then _
            outputBlock.Text &= "   ...is MustInherit" & vbLf

        If 0 <> (attr And TypeAttributes.Sealed) Then _
            outputBlock.Text &= "   ...is NotInheritable" & vbLf
   End Sub 
End Class 

' This example produces 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
using System;
using System.Reflection;

internal struct S
{
    public int X;
}

public abstract class Example
{
    protected sealed class NestedClass {}

    public interface INested {}

    private static System.Windows.Controls.TextBlock outputBlock;

    public static void Demo(System.Windows.Controls.TextBlock outputBlock)
    {
        Example.outputBlock = outputBlock;

        DisplayAttributes(typeof(Example));
        DisplayAttributes(typeof(NestedClass));
        DisplayAttributes(typeof(INested));
        DisplayAttributes(typeof(S));
    }

    private static void DisplayAttributes(Type t)
    {
        outputBlock.Text += "Attributes for type "+t.Name+":\n";

        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:
                outputBlock.Text += "   ...is not public\n";
                break;
            case TypeAttributes.Public:
                outputBlock.Text += "   ...is public\n";
                break;
            case TypeAttributes.NestedPublic:
                outputBlock.Text += "   ...is nested and public\n";
                break;
            case TypeAttributes.NestedPrivate:
                outputBlock.Text += "   ...is nested and private\n";
                break;
            case TypeAttributes.NestedFamANDAssem:
                outputBlock.Text += "   ...is nested, and inheritable only within the assembly" +
                   "\n         (cannot be declared in C#)\n";
                break;
            case TypeAttributes.NestedAssembly:
                outputBlock.Text += "   ...is nested and internal\n";
                break;
            case TypeAttributes.NestedFamily:
                outputBlock.Text += "   ...is nested and protected\n";
                break;
            case TypeAttributes.NestedFamORAssem:
                outputBlock.Text += "   ...is nested and protected internal\n";
                break;
        }

        TypeAttributes layout = attr & TypeAttributes.LayoutMask;
        switch (layout)
        {
            case TypeAttributes.AutoLayout:
                outputBlock.Text += "   ...is AutoLayout\n";
                break;
            case TypeAttributes.SequentialLayout:
                outputBlock.Text += "   ...is SequentialLayout\n";
                break;
            case TypeAttributes.ExplicitLayout:
                outputBlock.Text += "   ...is ExplicitLayout\n";
                break;
        }

        TypeAttributes classSemantics = attr & TypeAttributes.ClassSemanticsMask;
        switch (classSemantics)
        {
            case TypeAttributes.Class:
                if (t.IsValueType)
                {
                    outputBlock.Text += "   ...is a value type\n";
                }
                else
                {
                    outputBlock.Text += "   ...is a class\n";
                }
                break;
            case TypeAttributes.Interface:
                outputBlock.Text += "   ...is an interface\n";
                break;
        }

        if (0!=(attr & TypeAttributes.Abstract)) 
        {
            outputBlock.Text += "   ...is abstract\n";
        }

        if (0!=(attr & TypeAttributes.Sealed)) 
        {
            outputBlock.Text += "   ...is sealed\n";
        }
    }
}

/* This example produces 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
 */

Version Information

Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Platforms

Windows Phone

See Also

Reference

System.Reflection Namespace

Type..::.Attributes