MemberInfo.IsDefined 方法
在派生类中被重写时，指示是否 attributeType 的一个或多个实例应用于此成员。
**命名空间:**System.Reflection
**程序集:**mscorlib（在 mscorlib.dll 中）
语法
声明
Public MustOverride Function IsDefined ( _
attributeType As Type, _
inherit As Boolean _
) As Boolean
用法
Dim instance As MemberInfo
Dim attributeType As Type
Dim inherit As Boolean
Dim returnValue As Boolean
returnValue = instance.IsDefined(attributeType, inherit)
public abstract bool IsDefined (
Type attributeType,
bool inherit
)
public:
virtual bool IsDefined (
Type^ attributeType,
bool inherit
) abstract
public abstract boolean IsDefined (
Type attributeType,
boolean inherit
)
public abstract function IsDefined (
attributeType : Type,
inherit : boolean
) : boolean
参数
- attributeType
自定义属性应用于的 Type 对象。
- inherit
指定是否搜索该成员的继承链以查找这些属性。
返回值
如果 attributeType 的一个或多个实例应用于此成员，则为 true；否则为 false。
示例
下面的示例确定指定的属性是否应用于指定的成员。
Imports System
Imports System.Reflection
Imports Microsoft.VisualBasic
' Define a custom attribute with one named parameter.
<AttributeUsage(AttributeTargets.All)> Public Class MyAttribute
Inherits Attribute
Private myName As String
Public Sub New(ByVal name As String)
myName = name
End Sub 'New
Public ReadOnly Property Name() As String
Get
Return myName
End Get
End Property
End Class 'MyAttribute
' Define a class that has the custom attribute associated with one of its members.
Public Class MyClass1
<MyAttribute("This is an example attribute.")> Public Sub MyMethod(ByVal i As Integer)
Return
End Sub 'MyMethod
End Class 'MyClass1
Public Class MemberInfo_GetCustomAttributes_IsDefined
Public Shared Sub Main()
Try
' Get the type of MyClass1.
Dim myType As Type = GetType(MyClass1)
' Get the members associated with MyClass1.
Dim myMembers As MemberInfo() = myType.GetMembers()
' Display the attributes for each of the members of MyClass1.
Dim i As Integer
For i = 0 To myMembers.Length - 1
' Display the attribute if it is of type MyAttribute.
If myMembers(i).IsDefined(GetType(MyAttribute), False) Then
Dim myAttributes As [Object]() = myMembers(i).GetCustomAttributes(GetType(MyAttribute), False)
Console.WriteLine(ControlChars.Cr + "The attributes of type MyAttribute for the member {0} are: " + ControlChars.Cr, myMembers(i))
Dim j As Integer
For j = 0 To myAttributes.Length - 1
' Display the value associated with the attribute.
Console.WriteLine("The value of the attribute is : ""{0}""", CType(myAttributes(j), MyAttribute).Name)
Next j
End If
Next i
Catch e As Exception
Console.WriteLine("An exception occurred: {0}", e.Message)
End Try
End Sub 'Main
End Class 'MemberInfo_GetCustomAttributes_IsDefined
using System;
using System.Reflection;
// Define a custom attribute with one named parameter.
[AttributeUsage(AttributeTargets.All)]
public class MyAttribute : Attribute
{
private string myName;
public MyAttribute(string name)
{
myName = name;
}
public string Name
{
get
{
return myName;
}
}
}
// Define a class that has the custom attribute associated with one of its members.
public class MyClass1
{
[MyAttribute("This is an example attribute.")]
public void MyMethod(int i)
{
return;
}
}
public class MemberInfo_GetCustomAttributes_IsDefined
{
public static void Main()
{
try
{
// Get the type of MyClass1.
Type myType = typeof(MyClass1);
// Get the members associated with MyClass1.
MemberInfo[] myMembers = myType.GetMembers();
// Display the attributes for each of the members of MyClass1.
for(int i = 0; i < myMembers.Length; i++)
{
// Display the attribute if it is of type MyAttribute.
if(myMembers[i].IsDefined(typeof(MyAttribute), false))
{
Object[] myAttributes = myMembers[i].GetCustomAttributes(typeof(MyAttribute), false);
Console.WriteLine("\nThe attributes of type MyAttribute for the member {0} are: \n",
myMembers[i]);
for(int j = 0; j < myAttributes.Length; j++)
// Display the value associated with the attribute.
Console.WriteLine("The value of the attribute is : \"{0}\"",
((MyAttribute)myAttributes[j]).Name);
}
}
}
catch(Exception e)
{
Console.WriteLine("An exception occurred: {0}", e.Message);
}
}
}
using namespace System;
using namespace System::Reflection;
// Define a custom attribute with one named parameter.
[AttributeUsage(AttributeTargets::All)]
public ref class MyAttribute: public Attribute
{
private:
String^ myName;
public:
MyAttribute( String^ name )
{
myName = name;
}
property String^ Name
{
String^ get()
{
return myName;
}
}
};
// Define a class that has the custom attribute associated with one of its members.
public ref class MyClass1
{
public:
[MyAttribute("This is an example attribute.")]
void MyMethod( int i ){}
};
int main()
{
try
{
// Get the type of MyClass1.
Type^ myType = MyClass1::typeid;
// Get the members associated with MyClass1.
array<MemberInfo^>^myMembers = myType->GetMembers();
// Display the attributes for each of the members of MyClass1.
for ( int i = 0; i < myMembers->Length; i++ )
{
// Display the attribute if it is of type MyAttribute.
if ( myMembers[ i ]->IsDefined( MyAttribute::typeid, false ) )
{
array<Object^>^myAttributes = myMembers[ i ]->GetCustomAttributes( MyAttribute::typeid, false );
Console::WriteLine( "\nThe attributes of type MyAttribute for the member {0} are: \n", myMembers[ i ] );
for ( int j = 0; j < myAttributes->Length; j++ )
// Display the value associated with the attribute.
Console::WriteLine( "The value of the attribute is : \"{0}\"",
(safe_cast<MyAttribute^>(myAttributes[ j ]))->Name );
}
}
}
catch ( Exception^ e )
{
Console::WriteLine( "An exception occurred: {0}", e->Message );
}
}
import System.*;
import System.Reflection.*;
// Define a custom attribute with one named parameter.
/** @attribute AttributeUsage(AttributeTargets.All)
*/
public class MyAttribute extends Attribute
{
private String myName;
public MyAttribute(String name)
{
myName = name;
} //MyAttribute
/** @property
*/
public String get_Name()
{
return myName;
} //get_Name
} //MyAttribute
// Define a class that has the custom attribute associated
// with one of its members.
public class MyClass1
{
/** @attribute MyAttribute("This is an example attribute.")
*/
public void MyMethod(int i)
{
return;
} //MyMethod
} //MyClass1
public class MemberInfo_GetCustomAttributes_IsDefined
{
public static void main(String[] args)
{
try {
// Get the type of MyClass1.
Type myType = MyClass1.class.ToType();
// Get the members associated with MyClass1.
MemberInfo myMembers[] = myType.GetMembers();
// Display the attributes for each of the members of MyClass1.
for (int i = 0; i < myMembers.length; i++) {
// Display the attribute if it is of type MyAttribute.
if (((MemberInfo)myMembers.get_Item(i)).
IsDefined(MyAttribute.class.ToType(), false)) {
Object myAttributes[] = ((MemberInfo)myMembers.get_Item(i)).
GetCustomAttributes(MyAttribute.class.ToType(), false);
Console.WriteLine("\nThe attributes of type MyAttribute for"
+ " the member {0} are: \n", myMembers.get_Item(i));
for (int j = 0; j < myAttributes.length; j++) {
// Display the value associated with the attribute.
Console.WriteLine("The value of the attribute is : \""
+ "{0}\"", ((MyAttribute)myAttributes.get_Item(j)).
get_Name());
}
}
}
}
catch (System.Exception e) {
Console.WriteLine("An exception occurred: {0}", e.get_Message());
}
} //main
} //MemberInfo_GetCustomAttributes_IsDefined
平台
Windows 98、Windows 2000 SP4、Windows CE、Windows Millennium Edition、Windows Mobile for Pocket PC、Windows Mobile for Smartphone、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition
.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。
版本信息
.NET Framework
受以下版本支持：2.0、1.1、1.0
.NET Compact Framework
受以下版本支持：2.0、1.0