아티클
11/17/2011

TypeAttributes Enumeration

Microsoft Silverlight will reach end of support after October 2021. Learn more.

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

'Declaration
<FlagsAttribute> _
<ComVisibleAttribute(True)> _
Public Enumeration TypeAttributes

[FlagsAttribute]
[ComVisibleAttribute(true)]
public enum TypeAttributes

Members

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

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.

Note:
To run this example, see Building Examples That Use a Demo Method and a TextBlock Control.

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

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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