Attribute.Match 方法
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。
**命名空间:**System
**程序集:**mscorlib（在 mscorlib.dll 中）
语法
声明
Public Overridable Function Match ( _
obj As Object _
) As Boolean
用法
Dim instance As Attribute
Dim obj As Object
Dim returnValue As Boolean
returnValue = instance.Match(obj)
public virtual bool Match (
Object obj
)
public:
virtual bool Match (
Object^ obj
)
public boolean Match (
Object obj
)
public function Match (
obj : Object
) : boolean
参数
返回值
如果该实例等于 obj，则为 true；否则，为 false。
备注
此方法确定两个 Attribute 是否相等。其默认实现与执行值引用比较的 Equals 相同。重写此方法以实现对由本身有意义的组件组成的属性值（如标志或位域）的支持。
例如，请考虑一个值为被分成标志位域的二进制字段的属性。该属性的两个实例的标志集一个共有的，而所有其他标志都不同。Equals 方法无法确定这两个实例是否具有相同的标志集，但 Match 方法可以确定。
示例
下面的代码示例演示在 Attribute 上下文中 Match 的用法。
Imports System
Imports System.Reflection
Module DemoModule
' A custom attribute to allow 2 authors per method.
<AttributeUsage(AttributeTargets.Method)> _
Public Class AuthorsAttribute
Inherits Attribute
Public Sub New(ByVal name1 As String, ByVal name2 As String)
myAuthorName1 = name1
myAuthorName2 = name2
End Sub
Protected myAuthorName1 As String
Protected myAuthorName2 As String
Public Property AuthorName1() As String
Get
Return myAuthorName1
End Get
Set(ByVal Value As String)
myAuthorName1 = AuthorName1
End Set
End Property
Public Property AuthorName2() As String
Get
Return myAuthorName2
End Get
Set(ByVal Value As String)
myAuthorName2 = AuthorName2
End Set
End Property
' Use the hash code of the string objects and xor them together.
Public Overrides Function GetHashCode() As Integer
Return myAuthorName1.GetHashCode() Xor myAuthorName2.GetHashCode()
End Function
' Determine if the object is a match to this one.
Public Overrides Function Match(ByVal obj As Object) As Boolean
' Obviously a match.
If obj Is Me Then
Return True
End If
' Obviously we're not nothing, so no.
If obj Is Nothing Then
Return False
End If
If TypeOf obj Is AuthorsAttribute Then
' Combine the hash codes and see if they're unchanged.
Dim authObj As AuthorsAttribute = CType(obj, AuthorsAttribute)
Dim firstHash As Integer = authObj.GetHashCode() And GetHashCode()
If firstHash = GetHashCode() Then
Return True
Else
Return False
End If
Else
Return False
End If
End Function
End Class
' Add some authors to methods of a class.
Public Class TestClass1
<Authors("William Shakespeare", "Herman Melville")> _
Public Sub Method1()
End Sub
<Authors("Leo Tolstoy", "John Milton")> _
Public Sub Method2()
End Sub
End Class
' Add authors to a second class's methods.
Public Class TestClass2
<Authors("William Shakespeare", "Herman Melville")> _
Public Sub Method1()
End Sub
<Authors("Leo Tolstoy", "John Milton")> _
Public Sub Method2()
End Sub
<Authors("Francis Bacon", "Miguel Cervantes")> _
Public Sub Method3()
End Sub
End Class
Sub Main()
' Get the type for both classes to access their metadata.
Dim clsType1 As Type = GetType(TestClass1)
Dim clsType2 As Type = GetType(TestClass2)
Dim mInfo1 As MethodInfo
' Iterate through each method of the first class.
For Each mInfo1 In clsType1.GetMethods()
' Check each method for the Authors attribute.
Dim attr1 As Attribute = Attribute.GetCustomAttribute(mInfo1, _
GetType(AuthorsAttribute))
If Not attr1 Is Nothing And TypeOf attr1 Is AuthorsAttribute Then
Dim authAttr1 As AuthorsAttribute = _
CType(attr1, AuthorsAttribute)
' Display the authors.
Console.WriteLine("Method {0} was authored by {1} and {2}.", _
mInfo1.Name, authAttr1.AuthorName1, _
authAttr1.AuthorName2)
Dim mInfo2 As MethodInfo
' Iterate through each method of the second class.
For Each mInfo2 In clsType2.GetMethods()
' Check each method for the Authors attribute.
Dim attr2 As Attribute = Attribute.GetCustomAttribute( _
mInfo2, GetType(AuthorsAttribute))
If Not attr2 Is Nothing And _
TypeOf attr2 Is AuthorsAttribute Then
Dim authAttr2 As AuthorsAttribute = _
CType(attr2, AuthorsAttribute)
' Compare with the authors in the first class.
If authAttr2.Match(authAttr1) = True Then
Console.WriteLine("Method {0} in class {1} was " + _
"also authored by the same team.", _
mInfo2.Name, clsType2.Name)
End If
End If
Next
Console.WriteLine("")
End If
Next
End Sub
End Module
' Output:
' Method Method1 was authored by William Shakespeare and Herman Melville.
' Method Method1 in class TestClass2 was also authored by the same team.
'
' Method Method2 was authored by Leo Tolstoy and John Milton.
' Method Method2 in class TestClass2 was also authored by the same team.
using System;
using System.Reflection;
namespace MatchCS {
// A custom attribute to allow 2 authors per method.
public class AuthorsAttribute : Attribute {
public AuthorsAttribute(string name1, string name2) {
authorName1 = name1;
authorName2 = name2;
}
protected string authorName1;
protected string authorName2;
public string AuthorName1 {
get { return authorName1; }
set { authorName1 = AuthorName1; }
}
public string AuthorName2 {
get { return authorName2; }
set { authorName2 = AuthorName2; }
}
// Use the hash code of the string objects and xor them together.
public override int GetHashCode() {
return authorName1.GetHashCode() ^ authorName2.GetHashCode();
}
// Determine if the object is a match to this one.
public override bool Match(object obj) {
// Obviously a match.
if (obj == this)
return true;
// Obviously we're not null, so no.
if (obj == null)
return false;
if (obj is AuthorsAttribute)
// Combine the hash codes and see if they're unchanged.
return (((AuthorsAttribute)obj).GetHashCode() & GetHashCode())
== GetHashCode();
else
return false;
}
}
// Add some authors to methods of a class.
public class TestClass1 {
[Authors("William Shakespeare", "Herman Melville")]
public void Method1()
{}
[Authors("Leo Tolstoy", "John Milton")]
public void Method2()
{}
}
// Add authors to a second class's methods.
public class TestClass2 {
[Authors("William Shakespeare", "Herman Melville")]
public void Method1()
{}
[Authors("Leo Tolstoy", "John Milton")]
public void Method2()
{}
[Authors("William Shakespeare", "John Milton")]
public void Method3()
{}
}
class DemoClass {
static void Main(string[] args) {
// Get the type for both classes to access their metadata.
Type clsType1 = typeof(TestClass1);
Type clsType2 = typeof(TestClass2);
// Iterate through each method of the first class.
foreach(MethodInfo mInfo1 in clsType1.GetMethods()) {
// Check each method for the Authors attribute.
AuthorsAttribute authAttr1 = (AuthorsAttribute)
Attribute.GetCustomAttribute(mInfo1,
typeof(AuthorsAttribute));
if (authAttr1 != null) {
// Display the authors.
Console.WriteLine("Method {0} was authored by {1} " +
"and {2}.", mInfo1.Name,
authAttr1.AuthorName1,
authAttr1.AuthorName2);
// Iterate through each method of the second class.
foreach(MethodInfo mInfo2 in clsType2.GetMethods()) {
// Check each method for the Authors attribute.
AuthorsAttribute authAttr2 = (AuthorsAttribute)
Attribute.GetCustomAttribute(mInfo2,
typeof(AuthorsAttribute));
// Compare with the authors in the first class.
if (authAttr2 != null && authAttr2.Match(authAttr1))
Console.WriteLine("Method {0} in class {1} " +
"was authored by the same team.",
mInfo2.Name, clsType2.Name);
}
Console.WriteLine("");
}
}
}
}
}
/*
* Output:
* Method Method1 was authored by William Shakespeare and Herman Melville.
* Method Method1 in class TestClass2 was authored by the same team.
* Method Method2 was authored by Leo Tolstoy and John Milton.
* Method Method2 in class TestClass2 was authored by the same team.
*/
using namespace System;
using namespace System::Reflection;
// A custom attribute to allow 2 authors per method.
public ref class AuthorsAttribute: public Attribute
{
public:
AuthorsAttribute( String^ name1, String^ name2 )
{
authorName1 = name1;
authorName2 = name2;
}
protected:
String^ authorName1;
String^ authorName2;
public:
property String^ AuthorName1
{
String^ get()
{
return authorName1;
}
void set( String^ value )
{
authorName1 = value;
}
}
property String^ AuthorName2
{
String^ get()
{
return authorName2;
}
void set( String^ value )
{
authorName2 = value;
}
}
// Use the hash code of the string objects and xor them together.
virtual int GetHashCode() override
{
return authorName1->GetHashCode() ^ authorName2->GetHashCode();
}
// Determine if the object is a match to this one.
virtual bool Match( Object^ obj ) override
{
// Obviously a match.
if ( obj == this )
return true;
// Obviously we're not null, so no.
if ( obj == nullptr )
return false;
if ( dynamic_cast<AuthorsAttribute^>(obj) )
// Combine the hash codes and see if they're unchanged.
return (dynamic_cast<AuthorsAttribute^>(obj)->GetHashCode() & GetHashCode()) == GetHashCode();
else
return false;
}
};
// Add some authors to methods of a class.
public ref class TestClass1
{
public:
[Authors("William Shakespeare","Herman Melville")]
void Method1(){}
[Authors("Leo Tolstoy","John Milton")]
void Method2(){}
};
// Add authors to a second class's methods.
public ref class TestClass2
{
public:
[Authors("William Shakespeare","Herman Melville")]
void Method1(){}
[Authors("Leo Tolstoy","John Milton")]
void Method2(){}
[Authors("William Shakespeare","John Milton")]
void Method3(){}
};
int main()
{
// Get the type for both classes to access their metadata.
Type^ clsType1 = TestClass1::typeid;
Type^ clsType2 = TestClass2::typeid;
// Iterate through each method of the first class.
System::Collections::IEnumerator^ myEnum = clsType1->GetMethods()->GetEnumerator();
while ( myEnum->MoveNext() )
{
MethodInfo^ mInfo1 = safe_cast<MethodInfo^>(myEnum->Current);
// Check each method for the Authors attribute.
AuthorsAttribute^ authAttr1 = dynamic_cast<AuthorsAttribute^>(Attribute::GetCustomAttribute( mInfo1, AuthorsAttribute::typeid ));
if ( authAttr1 != nullptr )
{
// Display the authors.
Console::WriteLine( "Method {0} was authored by {1} and {2}.", mInfo1->Name, authAttr1->AuthorName1, authAttr1->AuthorName2 );
// Iterate through each method of the second class.
System::Collections::IEnumerator^ myEnum1 = clsType2->GetMethods()->GetEnumerator();
while ( myEnum1->MoveNext() )
{
MethodInfo^ mInfo2 = safe_cast<MethodInfo^>(myEnum1->Current);
// Check each method for the Authors attribute.
AuthorsAttribute^ authAttr2 = dynamic_cast<AuthorsAttribute^>(Attribute::GetCustomAttribute( mInfo2, AuthorsAttribute::typeid ));
// Compare with the authors in the first class.
if ( authAttr2 != nullptr && authAttr2->Match(authAttr1) )
Console::WriteLine( "Method {0} in class {1} was authored by the same team.", mInfo2->Name, clsType2->Name );
}
Console::WriteLine();
}
}
}
/*
* Output:
* Method Method1 was authored by William Shakespeare and Herman Melville.
* Method Method1 in class TestClass2 was authored by the same team.
* Method Method2 was authored by Leo Tolstoy and John Milton.
* Method Method2 in class TestClass2 was authored by the same team.
*/
package MatchJSL;
import System.*;
import System.Reflection.*;
// A custom attribute to allow 2 authors per method.
/** @attribute AttributeUsage(AttributeTargets.Method, AllowMultiple = true)
*/
public class AuthorsAttribute extends Attribute
{
public AuthorsAttribute(String name1, String name2)
{
authorName1 = name1;
authorName2 = name2;
} //AuthorsAttribute
protected String authorName1;
protected String authorName2;
/** @property
*/
public String get_AuthorName1()
{
return authorName1;
} //get_AuthorName1
/** @property
*/
public void set_AuthorName1(String value)
{
authorName1 = value;
} //set_AuthorName1
/** @property
*/
public String get_AuthorName2()
{
return authorName2;
} //get_AuthorName2
/** @property
*/
public void set_AuthorName2(String value)
{
authorName2 = value;
} //set_AuthorName2
// Use the hash code of the string objects and xor them together.
public int GetHashCode()
{
return authorName1.GetHashCode() ^ authorName2.GetHashCode();
} //GetHashCode
// Determine if the object is a match to this one.
public boolean Match(Object obj)
{
// Obviously a match.
if (obj.Equals(this)) {
return true;
}
// Obviously we're not null, so no.
if (obj == null) {
return false;
}
if (obj instanceof AuthorsAttribute) {
// Combine the hash codes and see if they're unchanged.
return (((AuthorsAttribute)obj).GetHashCode() & GetHashCode())
== GetHashCode();
}
else {
return false;
}
} //Match
} //AuthorsAttribute
// Add some authors to methods of a class.
public class TestClass1
{
/** @attribute Authors("William Shakespeare", "Herman Melville")
*/
public void Method1()
{
} //Method1
/** @attribute Authors("Leo Tolstoy", "John Milton")
*/
public void Method2()
{
} //Method2
} //TestClass1
// Add authors to a second class's methods.
public class TestClass2
{
/** @attribute Authors("William Shakespeare", "Herman Melville")
*/
public void Method1()
{
} //Method1
/** @attribute Authors("Leo Tolstoy", "John Milton")
*/
public void Method2()
{
} //Method2
/** @attribute Authors("William Shakespeare", "John Milton")
*/
public void Method3()
{
} //Method3
} //TestClass2
class DemoClass
{
public static void main(String[] args)
{
// Get the type for both classes to access their metadata.
Type clsType1 = TestClass1.class.ToType();
Type clsType2 = TestClass2.class.ToType();
// Iterate through each method of the first class.
for (int iCtr1 = 0; iCtr1 < clsType1.GetMethods().get_Length();
iCtr1++) {
MethodInfo mInfo1 =
(MethodInfo)clsType1.GetMethods().get_Item(iCtr1);
// Check each method for the Authors attribute.
AuthorsAttribute authAttr1 =
(AuthorsAttribute)Attribute.GetCustomAttribute(mInfo1,
AuthorsAttribute.class.ToType());
if (authAttr1 != null) {
// Display the authors.
Console.WriteLine("Method {0} was authored by {1} "
+ "and {2}.", mInfo1.get_Name(),
authAttr1.get_AuthorName1(), authAttr1.get_AuthorName2());
// Iterate through each method of the second class.
for (int iCtr2 = 0; iCtr2 < clsType1.GetMethods().get_Length();
iCtr2++) {
MethodInfo mInfo2 = (MethodInfo)clsType1.GetMethods().
get_Item(iCtr2);
// Check each method for the Authors attribute.
AuthorsAttribute authAttr2 = (AuthorsAttribute)Attribute.
GetCustomAttribute(mInfo2,
AuthorsAttribute.class.ToType());
// Compare with the authors in the first class.
if (authAttr2 != null && authAttr2.Match(authAttr1)) {
Console.WriteLine("Method {0} in class {1} "
+ "was authored by the same team.",
mInfo2.get_Name(), clsType2.get_Name());
}
}
Console.WriteLine("");
}
}
} //main
} //DemoClass
/*
* Output:
* Method Method1 was authored by William Shakespeare and Herman Melville.
* Method Method1 in class TestClass2 was authored by the same team.
* Method Method2 was authored by Leo Tolstoy and John Milton.
* Method Method2 in class TestClass2 was authored by the same team.
*/
import System;
import System.Reflection;
package MatchJS {
// A custom attribute to allow 2 authors per method.
AttributeUsage(AttributeTargets.Method) public class AuthorsAttribute extends Attribute {
public function AuthorsAttribute(name1 : String, name2 : String) {
authorName1 = name1;
authorName2 = name2;
}
protected var authorName1 : String;
protected var authorName2 : String ;
public function get AuthorName1() : String {
return authorName1;
}
public function set AuthorName1( value: String ) {
authorName1 = value;
}
public function get AuthorName2() : String {
return authorName2;
}
public function set AuthorName2(value : String){
authorName2 = AuthorName2;
}
// Use the hash code of the string objects and xor them together.
public override function GetHashCode() : int {
return authorName1.GetHashCode() ^ authorName2.GetHashCode();
}
// Determine if the object is a match to this one.
public override function Match(obj) : boolean {
// Obviously a match.
if (obj == this)
return true;
// Obviously we're not null, so no.
if (obj == null)
return false;
if (obj instanceof AuthorsAttribute)
// Combine the hash codes and see if they're unchanged.
return (AuthorsAttribute(obj).GetHashCode() & GetHashCode())
== GetHashCode();
else
return false;
}
}
// Add some authors to methods of a class.
public class TestClass1 {
Authors("William Shakespeare", "Herman Melville")
public function Method1() : void
{}
Authors("Leo Tolstoy", "John Milton")
public function Method2() : void
{}
}
// Add authors to a second class's methods.
public class TestClass2 {
Authors("William Shakespeare", "Herman Melville")
public function Method1() : void
{}
Authors("Leo Tolstoy", "John Milton")
public function Method2() : void
{}
Authors("William Shakespeare", "John Milton")
public function Method3() : void
{}
}
class DemoClass {
static function Main() : void {
// Get the type for both classes to access their metadata.
var clsType1 : Type = TestClass1;
var clsType2 : Type = TestClass2;
// Iterate through each method of the first class.
var methods1 : MethodInfo[] = clsType1.GetMethods();
for(var i : int in methods1) {
var mInfo1 : MethodInfo = methods1[i];
// Check each method for the Authors attribute.
var authAttr1 : AuthorsAttribute = AuthorsAttribute(
Attribute.GetCustomAttribute(mInfo1, AuthorsAttribute));
if (authAttr1 != null) {
// Display the authors.
Console.WriteLine("Method {0} was authored by {1} " +
"and {2}.", mInfo1.Name,
authAttr1.AuthorName1,
authAttr1.AuthorName2);
// Iterate through each method of the second class.
var methods2 : MethodInfo[] = clsType2.GetMethods()
for( var j : int in methods2) {
var mInfo2 : MethodInfo = methods2[j];
// Check each method for the Authors attribute.
var authAttr2 : AuthorsAttribute = AuthorsAttribute(
Attribute.GetCustomAttribute(mInfo2,
AuthorsAttribute));
// Compare with the authors in the first class.
if (authAttr2 != null && authAttr2.Match(authAttr1))
Console.WriteLine("Method {0} in class {1} " +
"was authored by the same team.",
mInfo2.Name, clsType2.Name);
}
Console.WriteLine("");
}
}
}
}
}
MatchJS.DemoClass.Main();
/*
* Output:
* Method Method1 was authored by William Shakespeare and Herman Melville.
* Method Method1 in class TestClass2 was authored by the same team.
* Method Method2 was authored by Leo Tolstoy and John Milton.
* Method Method2 in class TestClass2 was authored by the same team.
*/
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