DefaultMemberAttribute DefaultMemberAttribute DefaultMemberAttribute DefaultMemberAttribute Class

定义

public ref class DefaultMemberAttribute sealed : Attribute
[System.Runtime.InteropServices.ComVisible(true)]
[System.AttributeUsage(System.AttributeTargets.Class | System.AttributeTargets.Interface | System.AttributeTargets.Struct)]
[System.Serializable]
public sealed class DefaultMemberAttribute : Attribute
type DefaultMemberAttribute = class
    inherit Attribute
Public NotInheritable Class DefaultMemberAttribute
Inherits Attribute
继承
DefaultMemberAttributeDefaultMemberAttributeDefaultMemberAttributeDefaultMemberAttribute
属性

示例

下面的示例使用DefaultMemberAttribute属性将Age属性设为MyClass类的默认成员。The following example uses the DefaultMemberAttribute attribute to make the Age property the default member of the MyClass class.

using namespace System;
using namespace System::Reflection;
using namespace System::IO;

[DefaultMemberAttribute("Age")]
public ref class MyClass
{
public:
   void Name( String^ s ){}


   property int Age 
   {
      int get()
      {
         return 20;
      }

   }

};

int main()
{
   try
   {
      Type^ myType = MyClass::typeid;
      array<MemberInfo^>^memberInfoArray = myType->GetDefaultMembers();
      if ( memberInfoArray->Length > 0 )
      {
         System::Collections::IEnumerator^ myEnum = memberInfoArray->GetEnumerator();
         while ( myEnum->MoveNext() )
         {
            MemberInfo^ memberInfoObj = safe_cast<MemberInfo^>(myEnum->Current);
            Console::WriteLine( "The default member name is: {0}", memberInfoObj );
         }
      }
      else
      {
         Console::WriteLine( "No default members are available." );
      }
   }
   catch ( InvalidOperationException^ e ) 
   {
      Console::WriteLine( "InvalidOperationException: {0}", e->Message );
   }
   catch ( IOException^ e ) 
   {
      Console::WriteLine( "IOException: {0}", e->Message );
   }
   catch ( Exception^ e ) 
   {
      Console::WriteLine( "Exception: {0}", e->Message );
   }
}

using System;
using System.Reflection;
using System.IO;

[DefaultMemberAttribute("Age")]   
public class MyClass
{
    public void Name(String s) {}
    public int Age
    {
        get
        {
            return 20;
        }
    }
    public static void Main()
    {
        try
        {
            Type  myType = typeof(MyClass);
            MemberInfo[] memberInfoArray = myType.GetDefaultMembers();
            if (memberInfoArray.Length > 0)
            {
                foreach(MemberInfo memberInfoObj in memberInfoArray)
                {
                    Console.WriteLine("The default member name is: " + memberInfoObj.ToString());
                }
            }
            else
            {
                Console.WriteLine("No default members are available."); 
            }
        }
        catch(InvalidOperationException e)
        {
            Console.WriteLine("InvalidOperationException: " + e.Message);
        }
        catch(IOException e)
        {
            Console.WriteLine("IOException: " + e.Message);
        }
        catch(Exception e)
        {
            Console.WriteLine("Exception: " + e.Message);
        }
    }
}
Imports System.Reflection
Imports System.IO

<DefaultMemberAttribute("Age")> Public Class [MyClass]

    Public Sub Name(ByVal s As String)
    End Sub 'Name

    Public ReadOnly Property Age() As Integer
        Get
            Return 20
        End Get
    End Property

    Public Shared Sub Main()
        Try
            Dim myType As Type = GetType([MyClass])
            Dim memberInfoArray As MemberInfo() = myType.GetDefaultMembers()
            If memberInfoArray.Length > 0 Then
                Dim memberInfoObj As MemberInfo
                For Each memberInfoObj In memberInfoArray
                    Console.WriteLine("The default member name is: " + memberInfoObj.ToString())
                Next memberInfoObj
            Else
                Console.WriteLine("No default members are available.")
            End If
        Catch e As InvalidOperationException
            Console.WriteLine("InvalidOperationException: " + e.Message)
        Catch e As IOException
            Console.WriteLine("IOException: " + e.Message)
        Catch e As Exception
            Console.WriteLine("Exception: " + e.Message)
        End Try
    End Sub 'Main
End Class '[MyClass]

注解

如果属性具有参数并且属性的名称或其访问器之一与指定DefaultMemberAttribute的名称匹配,则会将属性作为索引器(Visual Basic 中的默认索引属性)导入。A property is imported as an indexer (default indexed property in Visual Basic) if the property has arguments and if the name of the property or one of its accessors matches the name specified by the DefaultMemberAttribute. DefaultMemberAttribute如果在包含类型上不存在,则该类型不具有索引器。If the DefaultMemberAttribute is not present on the containing type, then the type does not have an indexer. C#编译器在包含索引DefaultMemberAttribute器的任何类型上发出。The C# compiler emits the DefaultMemberAttribute on any type containing an indexer. 在C#中, DefaultMemberAttribute如果类型还声明了索引器,则手动将类型的属性特性为错误。In C# it is an error to manually attribute a type with the DefaultMemberAttribute if the type also declares an indexer.

构造函数

DefaultMemberAttribute(String) DefaultMemberAttribute(String) DefaultMemberAttribute(String) DefaultMemberAttribute(String)

初始化 DefaultMemberAttribute 类的新实例。Initializes a new instance of the DefaultMemberAttribute class.

属性

MemberName MemberName MemberName MemberName

从属性中获取名称。Gets the name from the attribute.

TypeId TypeId TypeId TypeId

在派生类中实现时,获取此 Attribute 的唯一标识符。When implemented in a derived class, gets a unique identifier for this Attribute.

(Inherited from Attribute)

方法

Equals(Object) Equals(Object) Equals(Object) Equals(Object)

返回一个值,该值指示此实例是否与指定的对象相等。Returns a value that indicates whether this instance is equal to a specified object.

(Inherited from Attribute)
GetHashCode() GetHashCode() GetHashCode() GetHashCode()

返回此实例的哈希代码。Returns the hash code for this instance.

(Inherited from Attribute)
GetType() GetType() GetType() GetType()

获取当前实例的 TypeGets the Type of the current instance.

(Inherited from Object)
IsDefaultAttribute() IsDefaultAttribute() IsDefaultAttribute() IsDefaultAttribute()

在派生类中重写时,指示此实例的值是否是派生类的默认值。When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class.

(Inherited from Attribute)
Match(Object) Match(Object) Match(Object) Match(Object)

当在派生类中重写时,返回一个指示此实例是否等于指定对象的值。When overridden in a derived class, returns a value that indicates whether this instance equals a specified object.

(Inherited from Attribute)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

创建当前 Object 的浅表副本。Creates a shallow copy of the current Object.

(Inherited from Object)
ToString() ToString() ToString() ToString()

返回表示当前对象的字符串。Returns a string that represents the current object.

(Inherited from Object)

显式界面实现

_Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr) _Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr) _Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr) _Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr)

将一组名称映射为对应的一组调度标识符。Maps a set of names to a corresponding set of dispatch identifiers.

(Inherited from Attribute)
_Attribute.GetTypeInfo(UInt32, UInt32, IntPtr) _Attribute.GetTypeInfo(UInt32, UInt32, IntPtr) _Attribute.GetTypeInfo(UInt32, UInt32, IntPtr) _Attribute.GetTypeInfo(UInt32, UInt32, IntPtr)

检索对象的类型信息,然后可以使用该信息获取接口的类型信息。Retrieves the type information for an object, which can be used to get the type information for an interface.

(Inherited from Attribute)
_Attribute.GetTypeInfoCount(UInt32) _Attribute.GetTypeInfoCount(UInt32) _Attribute.GetTypeInfoCount(UInt32) _Attribute.GetTypeInfoCount(UInt32)

检索对象提供的类型信息接口的数量(0 或 1)。Retrieves the number of type information interfaces that an object provides (either 0 or 1).

(Inherited from Attribute)
_Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr) _Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr) _Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr) _Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)

提供对某一对象公开的属性和方法的访问。Provides access to properties and methods exposed by an object.

(Inherited from Attribute)

适用于