BindingFlags Výčet

Definice

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

Dědičnost

Object

ValueType

Enum

BindingFlags

Atributy

FlagsAttribute SerializableAttribute ComVisibleAttribute

Pole

Příklady

Následující příklad ukazuje mnoho příznaků vazby.

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.
'-------------------------
'

Poznámky

Tyto BindingFlags řídicí vazby pro velké množství tříd v System, System.Reflectiona System.Runtime obory názvů, které vyvolat, vytvořit, získat, nastavit a najít členy a typy.

BindingFlags se používají v následujících Type metodách a dalších místech, například MethodBase.Invoke:

• MethodBase.Invoke

• GetMembers

• GetEvents

• InvokeMember

• Activator.CreateInstance

• GetConstructor

• GetConstructors

• GetMethod

• GetMethods

• GetField

• GetFields

• GetEvent

• GetProperty

• GetProperties

• GetMember

• FindMembers

InvokeMember a GetMethod jsou obzvláště důležité.

Příznaky vazeb lze kategorizovat podle toho, jak identifikují člena typu, jak je uvedeno v následující tabulce.

Následující tabulka uvádí převody provedené ve výchozím nastavení Binder.ChangeType. Tato tabulka platí zejména pro BindingFlags.ExactBinding příznak vazby. Obecný princip je, že ChangeType by měl provádět pouze rozšiřující převody, které nikdy neztratí data. Příkladem rozšiřujícího převodu je vynucení hodnoty, která je 32bitové celé číslo podepsané na hodnotu, která je 64bitové celé číslo se signedm. Liší se od zužujícího převodu, který může ztratit data. Příkladem zužujícího převodu je vynucení 64bitového celého čísla podepsaného na 32bitové celé číslo se signedm.

Při použití příznaku BindingFlags.ExactBinding vazby modeluje reflexe pravidla přístupnosti společného systému typů. Pokud je například volající ve stejném sestavení, volající nepotřebuje zvláštní oprávnění pro interní členy. Jinak volající potřebuje ReflectionPermission. To je konzistentní s vyhledáváním členů, které jsou chráněny, soukromé atd.