BindingFlags Enumerazione

Definizione

public enum class BindingFlags

[System.Flags]
public enum BindingFlags

[System.Flags]
[System.Serializable]
public enum BindingFlags

[System.Flags]
[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public enum BindingFlags

[<System.Flags>]
type BindingFlags = 

[<System.Flags>]
[<System.Serializable>]
type BindingFlags = 

[<System.Flags>]
[<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type BindingFlags = 

Public Enum BindingFlags

Ereditarietà

Object

ValueType

Enum

BindingFlags

Attributi

FlagsAttribute SerializableAttribute ComVisibleAttribute

Campi

Esempio

Nell'esempio seguente vengono illustrati molti flag di associazione.

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

//namespace BindingFlagsSnippet {
public ref class TestClass
{
public:
   String^ Name;

private:
   array<Object^>^ values;
   int methodCalled;

public:

   property Object^ Item [int]
   {
      Object^ get( int index )
      {
         return values[ index ];
      }

      void set( int index, Object^ value )
      {
         values[ index ] = value;
      }
   }

   property Object^ Value
   {
      Object^ get()
      {
         return "the value";
      }
   }

   TestClass() 
   {
      Name = "initialName";
      values = gcnew array<Object^> {(int^)0,1,2,3,4,5,6,7,8,9};
      methodCalled = 0;
   }
   
   TestClass(String^ initName)
   {
      Name = initName;
      values = gcnew array<Object^> {(int^)0,1,2,3,4,5,6,7,8,9};
      methodCalled = 0;
   }

   static void SayHello()
   {
      Console::WriteLine( "Hello" );
   }

   void AddUp()
   {
      methodCalled++;
      Console::WriteLine( "AddUp Called {0} times", methodCalled );
   }

   static double ComputeSum( double d1, double d2 )
   {
      return d1 + d2;
   }

   static void PrintName( String^ firstName, String^ lastName )
   {
      Console::WriteLine( "{0},{1}", lastName, firstName );
   }

   void PrintTime()
   {
      Console::WriteLine( DateTime::Now );
   }

   void Swap( interior_ptr<int> a, interior_ptr<int> b )
   {
      int x =  *a;
       *a =  *b;
       *b = x;
   }
};


[DefaultMemberAttribute("PrintTime")]
public ref class TestClass2
{
public:
   void PrintTime()
   {
      Console::WriteLine( DateTime::Now );
   }

};

public ref class Base
{
private:
    static int BaseOnlyPrivate = 0;
protected:
    static int BaseOnly = 0;
};

public ref class Derived : Base
{
public:
    static int DerivedOnly = 0;
};

public ref class MostDerived : Derived {};

void main()
{
   array<Object^>^ noArguments;

   // BindingFlags::InvokeMethod
   // Call a static method.
   Type^ t = TestClass::typeid;
   Console::WriteLine();
   Console::WriteLine( "Invoking a static method." );
   Console::WriteLine( "-------------------------" );
   t->InvokeMember( "SayHello", BindingFlags::InvokeMethod | BindingFlags::Public | BindingFlags::Static, 
         nullptr, nullptr, noArguments );

   // BindingFlags::InvokeMethod
   // Call an instance method.
   TestClass^ c = gcnew TestClass;
   Console::WriteLine();
   Console::WriteLine( "Invoking an instance method." );
   Console::WriteLine( "----------------------------" );
   c->GetType()->InvokeMember( "AddUp", BindingFlags::InvokeMethod, nullptr, c, noArguments );
   c->GetType()->InvokeMember( "AddUp", BindingFlags::InvokeMethod, nullptr, c, noArguments );

   // BindingFlags::InvokeMethod
   // Call a method with parameters.
   array<Object^>^args = {100.09,184.45};
   Object^ result;
   Console::WriteLine();
   Console::WriteLine( "Invoking a method with parameters." );
   Console::WriteLine( "---------------------------------" );
   result = t->InvokeMember( "ComputeSum", BindingFlags::InvokeMethod, nullptr, nullptr, args );
   Console::WriteLine( " {0} + {1} = {2}", args[ 0 ], args[ 1 ], result );

   // BindingFlags::GetField, SetField
   Console::WriteLine();
   Console::WriteLine( "Invoking a field (getting and setting.)" );
   Console::WriteLine( "--------------------------------------" );

   // Get a field value.
   result = t->InvokeMember( "Name", BindingFlags::GetField, nullptr, c, noArguments );
   Console::WriteLine( "Name == {0}", result );

   // Set a field.
   array<Object^>^obj2 = {"NewName"};
   t->InvokeMember( "Name", BindingFlags::SetField, nullptr, c, obj2 );
   result = t->InvokeMember( "Name", BindingFlags::GetField, nullptr, c, noArguments );
   Console::WriteLine( "Name == {0}", result );
   Console::WriteLine();
   Console::WriteLine( "Invoking an indexed property (getting and setting.)" );
   Console::WriteLine( "--------------------------------------------------" );

   // BindingFlags::GetProperty
   // Get an indexed property value.
   int index = 3;
   array<Object^>^obj3 = {index};
   result = t->InvokeMember( "Item", BindingFlags::GetProperty, nullptr, c, obj3 );
   Console::WriteLine( "Item->Item[ {0}] == {1}", index, result );

   // BindingFlags::SetProperty
   // Set an indexed property value.
   index = 3;
   array<Object^>^obj4 = {index,"NewValue"};
   t->InvokeMember( "Item", BindingFlags::SetProperty, nullptr, c, obj4 );
   result = t->InvokeMember( "Item", BindingFlags::GetProperty, nullptr, c, obj3 );
   Console::WriteLine( "Item->Item[ {0}] == {1}", index, result );
   Console::WriteLine();
   Console::WriteLine( "Getting a field or property." );
   Console::WriteLine( "----------------------------" );

   // BindingFlags::GetField
   // Get a field or property.
   result = t->InvokeMember( "Name", static_cast<BindingFlags>(BindingFlags::GetField | 
       BindingFlags::GetProperty), nullptr, c, noArguments );
   Console::WriteLine( "Name == {0}", result );

   // BindingFlags::GetProperty
   result = t->InvokeMember( "Value", static_cast<BindingFlags>(BindingFlags::GetField | 
       BindingFlags::GetProperty), nullptr, c, noArguments );
   Console::WriteLine( "Value == {0}", result );
   Console::WriteLine();
   Console::WriteLine( "Invoking a method with named parameters." );
   Console::WriteLine( "---------------------------------------" );

   // BindingFlags::InvokeMethod
   // Call a method using named parameters.
   array<Object^>^argValues = {"Mouse","Micky"};
   array<String^>^argNames = {"lastName","firstName"};
   t->InvokeMember( "PrintName", BindingFlags::InvokeMethod, nullptr, nullptr, argValues, nullptr, 
       nullptr, argNames );
   Console::WriteLine();
   Console::WriteLine( "Invoking a default member of a type." );
   Console::WriteLine( "------------------------------------" );

   // BindingFlags::Default
   // Call the default member of a type.
   Type^ t3 = TestClass2::typeid;
   t3->InvokeMember( "", static_cast<BindingFlags>(BindingFlags::InvokeMethod | BindingFlags::Default), 
        nullptr, gcnew TestClass2, noArguments );

   // BindingFlags::Static, NonPublic, and Public
   // Invoking a member with ref parameters.
   Console::WriteLine();
   Console::WriteLine( "Invoking a method with ref parameters." );
   Console::WriteLine( "--------------------------------------" );
   MethodInfo^ m = t->GetMethod( "Swap" );
   args = gcnew array<Object^>(2);
   args[ 0 ] = 1;
   args[ 1 ] = 2;
   m->Invoke( gcnew TestClass, args );
   Console::WriteLine( "{0}, {1}", args[ 0 ], args[ 1 ] );

   // BindingFlags::CreateInstance
   // Creating an instance with a parameterless constructor.
   Console::WriteLine();
   Console::WriteLine( "Creating an instance with a parameterless constructor." );
   Console::WriteLine( "------------------------------------------------------" );
   Object^ obj = t->InvokeMember( "TestClass", static_cast<BindingFlags>(BindingFlags::Public | 
       BindingFlags::Instance | BindingFlags::CreateInstance), nullptr, nullptr, noArguments );
   Console::WriteLine("Instance of {0} created.", obj->GetType()->Name);

   // Creating an instance with a constructor that has parameters.
   Console::WriteLine();
   Console::WriteLine( "Creating an instance with a constructor that has parameters." );
   Console::WriteLine( "------------------------------------------------------------" );
   obj = t->InvokeMember( "TestClass", static_cast<BindingFlags>(BindingFlags::Public | 
       BindingFlags::Instance | BindingFlags::CreateInstance), nullptr, nullptr, 
       gcnew array<Object^> { "Hello, World!" } );
   Console::WriteLine("Instance of {0} created with initial value '{1}'.", obj->GetType()->Name, 
       obj->GetType()->InvokeMember("Name", BindingFlags::GetField, nullptr, obj, noArguments));

   // BindingFlags::DeclaredOnly
   Console::WriteLine();
   Console::WriteLine( "DeclaredOnly instance members." );
   Console::WriteLine( "------------------------------" );
   array<System::Reflection::MemberInfo^>^memInfo = t->GetMembers( BindingFlags::DeclaredOnly | 
       BindingFlags::Instance | BindingFlags::Public);
   for ( int i = 0; i < memInfo->Length; i++ )
   {
      Console::WriteLine( memInfo[ i ]->Name );

   }

   // BindingFlags::IgnoreCase
   Console::WriteLine();
   Console::WriteLine( "Using IgnoreCase and invoking the PrintName method." );
   Console::WriteLine( "---------------------------------------------------" );
   t->InvokeMember( "printname", static_cast<BindingFlags>(BindingFlags::IgnoreCase | 
                BindingFlags::Static | BindingFlags::Public | BindingFlags::InvokeMethod), 
                nullptr, nullptr, gcnew array<Object^> {"Brad","Smith"});

   // BindingFlags::FlattenHierarchy
   Console::WriteLine();
   Console::WriteLine( "Using FlattenHierarchy to get inherited static protected and public members." );
   Console::WriteLine( "----------------------------------------------------------------------------" );
   array<FieldInfo^>^ finfos = MostDerived::typeid->GetFields(BindingFlags::NonPublic | 
         BindingFlags::Public | BindingFlags::Static | BindingFlags::FlattenHierarchy);
   for each (FieldInfo^ finfo in finfos)
   {
       Console::WriteLine("{0} defined in {1}.", finfo->Name, finfo->DeclaringType->Name);
   }

   Console::WriteLine();
   Console::WriteLine("Without FlattenHierarchy." );
   Console::WriteLine("-------------------------");
   finfos = MostDerived::typeid->GetFields(BindingFlags::NonPublic | BindingFlags::Public |
         BindingFlags::Static);
   for each (FieldInfo^ finfo in finfos)
   {
       Console::WriteLine("{0} defined in {1}.", finfo->Name, finfo->DeclaringType->Name);
   }
};

/* This example produces output similar to the following:

Invoking a static method.
-------------------------
Hello

Invoking an instance method.
----------------------------
AddUp Called 1 times
AddUp Called 2 times

Invoking a method with parameters.
---------------------------------
 100.09 + 184.45 = 284.54

Invoking a field (getting and setting.)
--------------------------------------
Name == initialName
Name == NewName

Invoking an indexed property (getting and setting.)
--------------------------------------------------
Item->Item[ 3] == 3
Item->Item[ 3] == NewValue

Getting a field or property.
----------------------------
Name == NewName
Value == the value

Invoking a method with named parameters.
---------------------------------------
Mouse,Micky

Invoking a default member of a type.
------------------------------------
12/23/2009 4:19:06 PM

Invoking a method with ref parameters.
--------------------------------------
2, 1

Creating an instance with a parameterless constructor.
------------------------------------------------------
Instance of TestClass created.

Creating an instance with a constructor that has parameters.
------------------------------------------------------------
Instance of TestClass created with initial value 'Hello, World!'.

DeclaredOnly instance members.
------------------------------
get_Item
set_Item
get_Value
AddUp
PrintTime
Swap
.ctor
.ctor
Value
Item
Name
methodCalled

Using IgnoreCase and invoking the PrintName method.
---------------------------------------------------
Smith,Brad

Using FlattenHierarchy to get inherited static protected and public members.
----------------------------------------------------------------------------
DerivedOnly defined in Derived.
BaseOnly defined in Base.

Without FlattenHierarchy.
-------------------------

 */

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

namespace BindingFlagsSnippet
{
    class Example
    {
        static void Main()
        {
            // BindingFlags.InvokeMethod
            // Call a static method.
            Type t = typeof (TestClass);

            Console.WriteLine();
            Console.WriteLine("Invoking a static method.");
            Console.WriteLine("-------------------------");
            t.InvokeMember ("SayHello", BindingFlags.InvokeMethod | BindingFlags.Public |
                BindingFlags.Static, null, null, new object [] {});

            // BindingFlags.InvokeMethod
            // Call an instance method.
            TestClass c = new TestClass ();
            Console.WriteLine();
            Console.WriteLine("Invoking an instance method.");
            Console.WriteLine("----------------------------");
            c.GetType().InvokeMember ("AddUp", BindingFlags.InvokeMethod, null, c, new object [] {});
            c.GetType().InvokeMember ("AddUp", BindingFlags.InvokeMethod, null, c, new object [] {});

            // BindingFlags.InvokeMethod
            // Call a method with parameters.
            object [] args = new object [] {100.09, 184.45};
            object result;
            Console.WriteLine();
            Console.WriteLine("Invoking a method with parameters.");
            Console.WriteLine("---------------------------------");
            result = t.InvokeMember ("ComputeSum", BindingFlags.InvokeMethod, null, null, args);
            Console.WriteLine ("{0} + {1} = {2}", args[0], args[1], result);

            // BindingFlags.GetField, SetField
            Console.WriteLine();
            Console.WriteLine("Invoking a field (getting and setting.)");
            Console.WriteLine("--------------------------------------");
            // Get a field value.
            result = t.InvokeMember ("Name", BindingFlags.GetField, null, c, new object [] {});
            Console.WriteLine ("Name == {0}", result);
            // Set a field.
            t.InvokeMember ("Name", BindingFlags.SetField, null, c, new object [] {"NewName"});
            result = t.InvokeMember ("Name", BindingFlags.GetField, null, c, new object [] {});
            Console.WriteLine ("Name == {0}", result);

            Console.WriteLine();
            Console.WriteLine("Invoking an indexed property (getting and setting.)");
            Console.WriteLine("--------------------------------------------------");
            // BindingFlags.GetProperty
            // Get an indexed property value.
            int  index = 3;
            result = t.InvokeMember ("Item", BindingFlags.GetProperty, null, c, new object [] {index});
            Console.WriteLine ("Item[{0}] == {1}", index, result);
            // BindingFlags.SetProperty
            // Set an indexed property value.
            index = 3;
            t.InvokeMember ("Item", BindingFlags.SetProperty, null, c, new object [] {index, "NewValue"});
            result = t.InvokeMember ("Item", BindingFlags.GetProperty , null, c, new object [] {index});
            Console.WriteLine ("Item[{0}] == {1}", index, result);

            Console.WriteLine();
            Console.WriteLine("Getting a field or property.");
            Console.WriteLine("----------------------------");
            // BindingFlags.GetField
            // Get a field or property.
            result = t.InvokeMember ("Name", BindingFlags.GetField | BindingFlags.GetProperty, null, c,
                new object [] {});
            Console.WriteLine ("Name == {0}", result);
            // BindingFlags.GetProperty
            result = t.InvokeMember ("Value", BindingFlags.GetField | BindingFlags.GetProperty, null, c,
                new object [] {});
            Console.WriteLine ("Value == {0}", result);

            Console.WriteLine();
            Console.WriteLine("Invoking a method with named parameters.");
            Console.WriteLine("---------------------------------------");
            // BindingFlags.InvokeMethod
            // Call a method using named parameters.
            object[] argValues = new object [] {"Mouse", "Micky"};
            String [] argNames = new String [] {"lastName", "firstName"};
            t.InvokeMember ("PrintName", BindingFlags.InvokeMethod, null, null, argValues, null, null,
                argNames);

            Console.WriteLine();
            Console.WriteLine("Invoking a default member of a type.");
            Console.WriteLine("------------------------------------");
            // BindingFlags.Default
            // Call the default member of a type.
            Type t3 = typeof (TestClass2);
            t3.InvokeMember ("", BindingFlags.InvokeMethod | BindingFlags.Default, null, new TestClass2(),
                new object [] {});

            // BindingFlags.Static, NonPublic, and Public
            // Invoking a member with ref parameters.
            Console.WriteLine();
            Console.WriteLine("Invoking a method with ref parameters.");
            Console.WriteLine("--------------------------------------");
            MethodInfo m = t.GetMethod("Swap");
            args = new object[2];
            args[0] = 1;
            args[1] = 2;
            m.Invoke(new TestClass(),args);
            Console.WriteLine ("{0}, {1}", args[0], args[1]);

            // BindingFlags.CreateInstance
            // Creating an instance with a parameterless constructor.
            Console.WriteLine();
            Console.WriteLine("Creating an instance with a parameterless constructor.");
            Console.WriteLine("------------------------------------------------------");
            object cobj = t.InvokeMember ("TestClass", BindingFlags.Public |
                BindingFlags.Instance | BindingFlags.CreateInstance,
                null, null, new object [] {});
            Console.WriteLine("Instance of {0} created.", cobj.GetType().Name);

            // Creating an instance with a constructor that has parameters.
            Console.WriteLine();
            Console.WriteLine("Creating an instance with a constructor that has parameters.");
            Console.WriteLine("------------------------------------------------------------");
            cobj = t.InvokeMember ("TestClass", BindingFlags.Public |
                BindingFlags.Instance | BindingFlags.CreateInstance,
                null, null, new object [] { "Hello, World!" });
            Console.WriteLine("Instance of {0} created with initial value '{1}'.", cobj.GetType().Name,
                cobj.GetType().InvokeMember("Name", BindingFlags.GetField, null, cobj, null));

            // BindingFlags.DeclaredOnly
            Console.WriteLine();
            Console.WriteLine("DeclaredOnly instance members.");
            Console.WriteLine("------------------------------");
            System.Reflection.MemberInfo[] memInfo =
                t.GetMembers(BindingFlags.DeclaredOnly | BindingFlags.Instance |
                BindingFlags.Public);
            for(int i=0;i<memInfo.Length;i++)
            {
                Console.WriteLine(memInfo[i].Name);
            }

            // BindingFlags.IgnoreCase
            Console.WriteLine();
            Console.WriteLine("Using IgnoreCase and invoking the PrintName method.");
            Console.WriteLine("---------------------------------------------------");
            t.InvokeMember("printname", BindingFlags.IgnoreCase | BindingFlags.Static |
                BindingFlags.Public | BindingFlags.InvokeMethod, null, null, new object[]
                {"Brad","Smith"});

            // BindingFlags.FlattenHierarchy
            Console.WriteLine();
            Console.WriteLine("Using FlattenHierarchy to get inherited static protected and public members." );
            Console.WriteLine("----------------------------------------------------------------------------");
            FieldInfo[] finfos = typeof(MostDerived).GetFields(BindingFlags.NonPublic | BindingFlags.Public |
                  BindingFlags.Static | BindingFlags.FlattenHierarchy);
            foreach (FieldInfo finfo in finfos)
            {
                Console.WriteLine("{0} defined in {1}.", finfo.Name, finfo.DeclaringType.Name);
            }

            Console.WriteLine();
            Console.WriteLine("Without FlattenHierarchy." );
            Console.WriteLine("-------------------------");
            finfos = typeof(MostDerived).GetFields(BindingFlags.NonPublic | BindingFlags.Public |
                  BindingFlags.Static);
            foreach (FieldInfo finfo in finfos)
            {
                Console.WriteLine("{0} defined in {1}.", finfo.Name, finfo.DeclaringType.Name);
            }
        }
    }

    public class TestClass
    {
        public String Name;
        private Object [] values = new Object [] {0, 1,2,3,4,5,6,7,8,9};

        public Object this [int index]
        {
            get
            {
                return values[index];
            }
            set
            {
                values[index] = value;
            }
        }

        public Object Value
        {
            get
            {
                return "the value";
            }
        }

        public TestClass () : this("initialName") {}
        public TestClass (string initName)
        {
            Name = initName;
        }

        int methodCalled = 0;

        public static void SayHello ()
        {
            Console.WriteLine ("Hello");
        }

        public void AddUp ()
        {
            methodCalled++;
            Console.WriteLine ("AddUp Called {0} times", methodCalled);
        }

        public static double ComputeSum (double d1, double d2)
        {
            return d1 + d2;
        }

        public static void PrintName (String firstName, String lastName)
        {
            Console.WriteLine ("{0},{1}", lastName,firstName);
        }

        public void PrintTime ()
        {
            Console.WriteLine (DateTime.Now);
        }

        public void Swap(ref int a, ref int b)
        {
            int x = a;
            a = b;
            b = x;
        }
    }

    [DefaultMemberAttribute ("PrintTime")]
    public class TestClass2
    {
        public void PrintTime ()
        {
            Console.WriteLine (DateTime.Now);
        }
    }

    public class Base
    {
        static int BaseOnlyPrivate = 0;
        protected static int BaseOnly = 0;
    }
    public class Derived : Base
    {
        public static int DerivedOnly = 0;
    }
    public class MostDerived : Derived {}
}

/* This example produces output similar to the following:

Invoking a static method.
-------------------------
Hello

Invoking an instance method.
----------------------------
AddUp Called 1 times
AddUp Called 2 times

Invoking a method with parameters.
---------------------------------
100.09 + 184.45 = 284.54

Invoking a field (getting and setting.)
--------------------------------------
Name == initialName
Name == NewName

Invoking an indexed property (getting and setting.)
--------------------------------------------------
Item[3] == 3
Item[3] == NewValue

Getting a field or property.
----------------------------
Name == NewName
Value == the value

Invoking a method with named parameters.
---------------------------------------
Mouse,Micky

Invoking a default member of a type.
------------------------------------
12/23/2009 4:29:21 PM

Invoking a method with ref parameters.
--------------------------------------
2, 1

Creating an instance with a parameterless constructor.
------------------------------------------------------
Instance of TestClass created.

Creating an instance with a constructor that has parameters.
------------------------------------------------------------
Instance of TestClass created with initial value 'Hello, World!'.

DeclaredOnly instance members.
------------------------------
get_Item
set_Item
get_Value
AddUp
PrintTime
Swap
.ctor
.ctor
Item
Value
Name

Using IgnoreCase and invoking the PrintName method.
---------------------------------------------------
Smith,Brad

Using FlattenHierarchy to get inherited static protected and public members.
----------------------------------------------------------------------------
DerivedOnly defined in Derived.
BaseOnly defined in Base.

Without FlattenHierarchy.
-------------------------

 */

Imports System.Reflection
Imports System.IO

Class Invoke

    Public Shared Sub Main()
        ' BindingFlags.InvokeMethod
        ' Call a static method.
        Dim t As Type = GetType(TestClass)

        Console.WriteLine()
        Console.WriteLine("Invoking a static method.")
        Console.WriteLine("-------------------------")
        t.InvokeMember("SayHello", BindingFlags.InvokeMethod Or BindingFlags.Public _
            Or BindingFlags.Static, Nothing, Nothing, New Object() {})

        ' BindingFlags.InvokeMethod
        ' Call an instance method.
        Dim c As New TestClass()
        Console.WriteLine()
        Console.WriteLine("Invoking an instance method.")
        Console.WriteLine("----------------------------")
        c.GetType().InvokeMember("AddUp", BindingFlags.InvokeMethod, Nothing, c, New Object() {})
        c.GetType().InvokeMember("AddUp", BindingFlags.InvokeMethod, Nothing, c, New Object() {})

        ' BindingFlags.InvokeMethod
        ' Call a method with parameters.
        Dim args() As Object = {100.09, 184.45}
        Dim result As Object
        Console.WriteLine()
        Console.WriteLine("Invoking a method with parameters.")
        Console.WriteLine("---------------------------------")
        result = t.InvokeMember("ComputeSum", BindingFlags.InvokeMethod, Nothing, Nothing, args)
        Console.WriteLine("{0} + {1} = {2}", args(0), args(1), result)

        ' BindingFlags.GetField, SetField
        Console.WriteLine()
        Console.WriteLine("Invoking a field (getting and setting.)")
        Console.WriteLine("--------------------------------------")
        ' Get a field value.
        result = t.InvokeMember("Name", BindingFlags.GetField, Nothing, c, New Object() {})
        Console.WriteLine("Name == {0}", result)
        ' Set a field.
        t.InvokeMember("Name", BindingFlags.SetField, Nothing, c, New Object() {"NewName"})
        result = t.InvokeMember("Name", BindingFlags.GetField, Nothing, c, New Object() {})
        Console.WriteLine("Name == {0}", result)

        Console.WriteLine()
        Console.WriteLine("Invoking an indexed property (getting and setting.)")
        Console.WriteLine("--------------------------------------------------")
        ' BindingFlags.GetProperty 
        ' Get an indexed property value.
        Dim index As Integer = 3
        result = t.InvokeMember("Item", BindingFlags.GetProperty, Nothing, c, New Object() {index})
        Console.WriteLine("Item[{0}] == {1}", index, result)
        ' BindingFlags.SetProperty
        ' Set an indexed property value.
        index = 3
        t.InvokeMember("Item", BindingFlags.SetProperty, Nothing, c, New Object() {index, "NewValue"})
        result = t.InvokeMember("Item", BindingFlags.GetProperty, Nothing, c, New Object() {index})
        Console.WriteLine("Item[{0}] == {1}", index, result)

        Console.WriteLine()
        Console.WriteLine("Getting a field or property.")
        Console.WriteLine("----------------------------")
        ' BindingFlags.GetField
        ' Get a field or property.
        result = t.InvokeMember("Name", BindingFlags.GetField Or BindingFlags.GetProperty, Nothing, _
            c, New Object() {})
        Console.WriteLine("Name == {0}", result)
        ' BindingFlags.GetProperty
        result = t.InvokeMember("Value", BindingFlags.GetField Or BindingFlags.GetProperty, Nothing, _
            c, New Object() {})
        Console.WriteLine("Value == {0}", result)

        Console.WriteLine()
        Console.WriteLine("Invoking a method with named parameters.")
        Console.WriteLine("---------------------------------------")
        ' BindingFlags.InvokeMethod
        ' Call a method using named parameters.
        Dim argValues() As Object = {"Mouse", "Micky"}
        Dim argNames() As [String] = {"lastName", "firstName"}
        t.InvokeMember("PrintName", BindingFlags.InvokeMethod, Nothing, Nothing, argValues, Nothing, _
            Nothing, argNames)

        Console.WriteLine()
        Console.WriteLine("Invoking a default member of a type.")
        Console.WriteLine("------------------------------------")
        ' BindingFlags.Default
        ' Call the default member of a type.
        Dim t3 As Type = GetType(TestClass2)
        t3.InvokeMember("", BindingFlags.InvokeMethod Or BindingFlags.Default, Nothing, _
            New TestClass2(), New Object() {})

        Console.WriteLine()
        Console.WriteLine("Invoking a method with ByRef parameters.")
        Console.WriteLine("----------------------------------------")
        ' BindingFlags.Static, NonPublic, and Public
        ' Invoking a member by reference.
        Dim m As MethodInfo = t.GetMethod("Swap")
        args = New Object(1) {}
        args(0) = 1
        args(1) = 2
        m.Invoke(New TestClass(), args)
        Console.WriteLine("{0}, {1}", args(0), args(1))

        ' BindingFlags.CreateInstance
        ' Creating an instance.
        Console.WriteLine()
        Console.WriteLine("Creating an instance with parameterless constructor.")
        Console.WriteLine("----------------------------------------------------")
        Dim obj As Object = GetType(TestClass).InvokeMember("TestClass", BindingFlags.CreateInstance, _
            Nothing, Nothing, New Object() {})
        Console.WriteLine("Instance of {0} created.", obj.GetType().Name)

        Console.WriteLine()
        Console.WriteLine("Creating an instance with a constructor that has parameters.")
        Console.WriteLine("------------------------------------------------------------")
        obj = GetType(TestClass).InvokeMember("TestClass", BindingFlags.CreateInstance, Nothing, _
            Nothing, New Object() { "Hello, World!" })
        Console.WriteLine("Instance of {0} created with initial value '{1}'.", obj.GetType().Name, _
            obj.GetType().InvokeMember("Name", BindingFlags.GetField, Nothing, obj, Nothing))

        ' BindingFlags.DeclaredOnly
        Console.WriteLine()
        Console.WriteLine("DeclaredOnly instance members.")
        Console.WriteLine("------------------------------")
        Dim memInfo As System.Reflection.MemberInfo() = t.GetMembers(BindingFlags.DeclaredOnly Or _
            BindingFlags.Public Or BindingFlags.Instance)
        Dim i As Integer
        For i = 0 To memInfo.Length - 1
            Console.WriteLine(memInfo(i).Name)
        Next i

        ' BindingFlags.IgnoreCase
        Console.WriteLine()
        Console.WriteLine("Using IgnoreCase and invoking the PrintName method.")
        Console.WriteLine("---------------------------------------------------")
        t.InvokeMember("printname", BindingFlags.IgnoreCase Or BindingFlags.Public Or _
            BindingFlags.Static Or BindingFlags.InvokeMethod, Nothing, Nothing, _
            New Object() {"Brad", "Smith"})

        ' BindingFlags.FlattenHierarchy
        Console.WriteLine()
        Console.WriteLine("Using FlattenHierarchy to get inherited static protected and public members." )
        Console.WriteLine("----------------------------------------------------------------------------")
        Dim finfos() As FieldInfo = GetType(MostDerived).GetFields(BindingFlags.NonPublic Or _
              BindingFlags.Public Or BindingFlags.Static Or BindingFlags.FlattenHierarchy)
        For Each finfo As FieldInfo In finfos
            Console.WriteLine("{0} defined in {1}.", finfo.Name, finfo.DeclaringType.Name)
        Next

        Console.WriteLine()
        Console.WriteLine("Without FlattenHierarchy." )
        Console.WriteLine("-------------------------")
        finfos = GetType(MostDerived).GetFields(BindingFlags.NonPublic Or BindingFlags.Public Or _
              BindingFlags.Static)
        For Each finfo As FieldInfo In finfos
            Console.WriteLine("{0} defined in {1}.", finfo.Name, finfo.DeclaringType.Name)
        Next
    End Sub
End Class

Public Class TestClass
    Public Name As String
    Private values() As [Object] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}

    Default Public Property Item(ByVal index As Integer) As [Object]
        Get
            Return values(index)
        End Get
        Set(ByVal Value As [Object])
            values(index) = Value
        End Set
    End Property

    Public ReadOnly Property Value() As [Object]
        Get
            Return "the value"
        End Get
    End Property

    Public Sub New(ByVal initName As String)
        Name = initName
    End Sub 

    Public Sub New()
        MyClass.New("initialName")
    End Sub 

    Private methodCalled As Integer = 0

    Public Shared Sub SayHello()
        Console.WriteLine("Hello")
    End Sub 

    Public Sub AddUp()
        methodCalled += 1
        Console.WriteLine("AddUp Called {0} times", methodCalled)
    End Sub 

    Public Shared Function ComputeSum(ByVal d1 As Double, ByVal d2 As Double) As Double
        Return d1 + d2
    End Function 

    Public Shared Sub PrintName(ByVal firstName As [String], ByVal lastName As [String])
        Console.WriteLine("{0},{1}", lastName, firstName)
    End Sub 

    Public Sub PrintTime()
        Console.WriteLine(DateTime.Now)
    End Sub 

    Public Sub Swap(ByRef a As Integer, ByRef b As Integer)
        Dim x As Integer = a
        a = b
        b = x
    End Sub
End Class

<DefaultMemberAttribute("PrintTime")> _
Public Class TestClass2

    Public Sub PrintTime()
        Console.WriteLine(DateTime.Now)
    End Sub 
End Class

Public Class Base
    Shared BaseOnlyPrivate As Integer = 0
    Protected Shared BaseOnly As Integer = 0
End Class

Public Class Derived 
    Inherits Base
    Public Shared DerivedOnly As Integer = 0
End Class

Public Class MostDerived 
    Inherits Derived
End Class

' This example produces output similar to the following:
'
'Invoking a static method.
'-------------------------
'Hello
'
'Invoking an instance method.
'----------------------------
'AddUp Called 1 times
'AddUp Called 2 times
'
'Invoking a method with parameters.
'---------------------------------
'100.09 + 184.45 = 284.54
'
'Invoking a field (getting and setting.)
'--------------------------------------
'Name == initialName
'Name == NewName
'
'Invoking an indexed property (getting and setting.)
'--------------------------------------------------
'Item[3] == 3
'Item[3] == NewValue
'
'Getting a field or property.
'----------------------------
'Name == NewName
'Value == the value
'
'Invoking a method with named parameters.
'---------------------------------------
'Mouse,Micky
'
'Invoking a default member of a type.
'------------------------------------
'12/23/2009 4:34:22 PM
'
'Invoking a method with ByRef parameters.
'----------------------------------------
'2, 1
'
'Creating an instance with parameterless constructor.
'----------------------------------------------------
'Instance of TestClass created.
'
'Creating an instance with a constructor that has parameters.
'------------------------------------------------------------
'Instance of TestClass created with initial value 'Hello, World!'.
'
'DeclaredOnly instance members.
'------------------------------
'get_Item
'set_Item
'get_Value
'AddUp
'PrintTime
'Swap
'.ctor
'.ctor
'Item
'Value
'Name
'
'Using IgnoreCase and invoking the PrintName method.
'---------------------------------------------------
'Smith,Brad
'
'Using FlattenHierarchy to get inherited static protected and public members.
'----------------------------------------------------------------------------
'DerivedOnly defined in Derived.
'BaseOnly defined in Base.
'
'Without FlattenHierarchy.
'-------------------------
'

Commenti

Queste BindingFlags associazioni di controllo per molte classi negli Systemspazi dei nomi , System.Reflectione System.Runtime che richiamano, creano, ottengono, impostano e trovano membri e tipi.

BindingFlags vengono usati nei metodi seguenti Type e in altre posizioni, ad MethodBase.Invokeesempio :

• MethodBase.Invoke

• GetMembers

• GetEvents

• InvokeMember

• Activator.CreateInstance

• GetConstructor

• GetConstructors

• GetMethod

• GetMethods

• GetField

• GetFields

• GetEvent

• GetProperty

• GetProperties

• GetMember

• FindMembers

InvokeMember e GetMethod sono particolarmente importanti.

I flag di associazione possono essere classificati in base al modo in cui identificano un membro del tipo, come indicato nella tabella seguente.

Nella tabella seguente sono elencate le coercioni eseguite dal valore predefinito Binder.ChangeType. Questa tabella si applica soprattutto al flag di BindingFlags.ExactBinding associazione. Il principio generale è che ChangeType deve eseguire solo coercioni ampliati, che non perderanno mai dati. Un esempio di coercizione di estensione consiste nel coercing di un valore con segno a 32 bit su un valore intero con segno a 64 bit. Questo è distinto da una coercizione ristretta, che può perdere dati. Un esempio di coercizione ristretta prevede la coercing di un intero con segno a 64 bit in un intero con segno a 32 bit.

Quando viene usato il BindingFlags.ExactBinding flag di associazione, la reflection modella le regole di accessibilità del sistema di tipi comuni. Ad esempio, se il chiamante si trova nello stesso assembly, il chiamante non richiede autorizzazioni speciali per i membri interni. In caso contrario, il chiamante necessita ReflectionPermissiondi . Ciò è coerente con la ricerca di membri protetti, privati e così via.

Si applica a