MethodBase.IsHideBySig-Eigenschaft

Artikel
08/20/2007

Ruft einen Wert ab, der angibt, ob nur ein Member derselben Art mit einer identischen Signatur in der abgeleiteten Klasse verborgen ist.

Namespace: System.Reflection
Assembly: mscorlib (in mscorlib.dll)

Syntax

'Declaration
Public ReadOnly Property IsHideBySig As Boolean
'Usage
Dim instance As MethodBase
Dim value As Boolean

value = instance.IsHideBySig

public bool IsHideBySig { get; }

public:
virtual property bool IsHideBySig {
    bool get () sealed;
}

/** @property */
public final boolean get_IsHideBySig ()

public final function get IsHideBySig () : boolean

Eigenschaftenwert

true, wenn der Member durch die Signatur verborgen ist, andernfalls false.

Hinweise

Wenn ein Member in einer abgeleiteten Klasse mit dem C#-Modifizierer new oder dem Visual Basic-Modifizierer Shadows deklariert wurde, kann er einen Member desselben Namens in der Basisklasse verdecken. C# verdeckt Basisklassenmember über die Signatur. Das heißt, wenn der Basisklassenmember über mehrere Überladungen verfügt, wird nur die verdeckt, die über eine identische Signatur verfügt. Im Gegensatz dazu verdeckt Visual Basic alle Überladungen der Basisklasse. Daher gibt IsHideBySig für einen mit dem Visual Basic-Modifizierer Shadows deklarierten Member false zurück und true, wenn ein Member mit dem C#-Modifizierer new deklariert wurde.

Beispiel

Das folgende Codebeispiel enthält eine Basisklasse mit einer überladenen Methode und eine abgeleitete Klasse, die eine dieser Überladungen verdeckt. In der Visual Basic-Version des Codebeispiels gibt die IsHideBySig-Eigenschaft für den Member in der abgeleiteten Klasse false zurück. Im C#-Codebeispiel gibt die Eigenschaft für den Member in der abgeleiteten Klasse true zurück.

Imports System
Imports System.Reflection

' The base class B contains an overloaded method M.
'
Public Class B
    Public Overridable Sub M()
        Console.WriteLine("B's M()")
    End Sub
    Public Overridable Sub M(ByVal x As Integer)
        Console.WriteLine("B's M({0})", x)
    End Sub
End Class

' The derived class D hides the inherited method M.
'
Public Class D
    Inherits B
    Shadows Public Sub M(ByVal i As Integer)
        Console.WriteLine("D's M({0})", i)
    End Sub
End Class

Public Class Test
    Public Shared Sub Main()
        Dim dinst As New D()
        ' In Visual Basic, the method in the derived class hides by
        ' name, rather than by signature.  Thus, although a list of all the 
        ' overloads of M shows three overloads, only one can be called from
        ' class D.  
        '
        Console.WriteLine("------ List the overloads of M in the derived class D ------")
        Dim t As Type = dinst.GetType()
        For Each minfo As MethodInfo In t.GetMethods()
            If minfo.Name = "M" Then Console.WriteLine( _
                "Overload of M: {0}  IsHideBySig = {1}, DeclaringType = {2}", _
                minfo, minfo.IsHideBySig, minfo.DeclaringType)
        Next

        ' The method M in the derived class hides the method in B.
        '
        Console.WriteLine("------ Call the overloads of M available in D ------")
        ' The following line causes a compile error, because both overloads
        ' in the base class are hidden.  Contrast this with C#, where only 
        ' one of the overloads of B would be hidden.
        'dinst.M()
        dinst.M(42)
        
        ' If D is cast to the base type B, both overloads of the 
        ' shadowed method can be called.
        '
        Console.WriteLine("------ Call the shadowed overloads of M ------")
        Dim binst As B = dinst
        binst.M()
        binst.M(42)         
    End Sub 'Main
End Class 'Test

' This code example produces the following output:
' ------ List the overloads of M in the derived class D ------
' Overload of M: Void M(Int32)  IsHideBySig = False, DeclaringType = B
' Overload of M: Void M()  IsHideBySig = False, DeclaringType = B
' Overload of M: Void M(Int32)  IsHideBySig = False, DeclaringType = D
' ------ Call the overloads of M available in D ------
' D's M(42)
' ------ Call the shadowed overloads of M ------
' B's M()
' B's M(42)

using System;
using System.Reflection;

// The base class B contains an overloaded method M.
//
public class B
{
    public virtual void M()
    {
        Console.WriteLine("B's M()");
    }
    public virtual void M(int x)
    {
        Console.WriteLine("B's M({0})", x);
    }
}

// The derived class D hides one overload of the inherited 
// method M.
//
public class D:
    B
{
    new public void M(int i)
    {
        Console.WriteLine("D's M({0})", i);
    }
}

public class Test
{
    public static void Main()
    {
        D dinst = new D();
        // In C#, the method in the derived class hides by name and by
        // signature, so the overload in the derived class hides only one
        // of the overloads in the base class.
        //
        Console.WriteLine("------ List the overloads of M in the derived class D ------");
        Type t = dinst.GetType();
        foreach( MethodInfo minfo in t.GetMethods() )
        {
            if (minfo.Name=="M") {Console.WriteLine("Overload of M: {0}  IsHideBySig = {1}, DeclaringType = {2}", minfo, minfo.IsHideBySig, minfo.DeclaringType);}
        }

        // The method M in the derived class hides one overload of the 
        // method in B.  Contrast this with Visual Basic, which hides by
        // name instead of by name and signature.  In Visual Basic, the
        // parameterless overload of M would be unavailable from D.
        //
        Console.WriteLine("------ Call the overloads of M available in D ------");
        dinst.M();
        dinst.M(42);
        
        // If D is cast to the base type B, both overloads of the 
        // shadowed method can be called.
        //
        Console.WriteLine("------ Call the shadowed overloads of M ------");
        B binst = dinst;
        binst.M();
        binst.M(42);
    } //Main
} //Test

/* This code example produces the following output:

------ List the overloads of M in the derived class D ------
Overload of M: Void M(Int32)  IsHideBySig = True, DeclaringType = B
Overload of M: Void M()  IsHideBySig = True, DeclaringType = B
Overload of M: Void M(Int32)  IsHideBySig = True, DeclaringType = D
------ Call the overloads of M available in D ------
B's M()
D's M(42)
------ Call the shadowed overloads of M ------
B's M()
B's M(42)
*/

using namespace System;
using namespace System::Reflection;

// The base class Parent contains an overloaded method PrintCall.
//
public ref class Parent
{
public:
    virtual void PrintCall()
    {
        Console::WriteLine("Parent's PrintCall()");
    }
public:
    virtual void PrintCall(int x)
    {
        Console::WriteLine("Parent's PrintCall({0})", x);
    }
};

// The derived class Child hides one overload of the inherited 
// method PrintCall.
//
public ref class Child : public Parent
{
public:
    void PrintCall(int i) new
    {
        Console::WriteLine("Child's PrintCall({0})", i);
    }
};

int main()
{
    Child^ childInstance = gcnew Child();

    // In C#, the method in the derived class hides by name and by
    // signature, so the overload in the derived class hides only one
    // of the overloads in the base class.
    //
    Console::WriteLine("------ List the overloads of PrintCall in the " +
        "derived class Child ------");
    Type^ t = childInstance->GetType();
    for each(MethodInfo^ minfo in t->GetMethods())
    {
        if (minfo->Name == "PrintCall")
        {
            Console::WriteLine("Overload of PrintCall: {0}" +
                " IsHideBySig = {1}, DeclaringType = {2}", 
                minfo, minfo->IsHideBySig, minfo->DeclaringType);
        }
    }

    // The method PrintCall in the derived class hides one overload of the 
    // method in Parent.  Contrast this with Visual Basic, which hides by
    // name instead of by name and signature.  In Visual Basic, the
    // parameterless overload of PrintCall would be unavailable from Child.
    //
    Console::WriteLine(
        "------ Call the overloads of PrintCall available in Child ------");
    childInstance->PrintCall();
    childInstance->PrintCall(42);

    // If Child is cast to the base type Parent, both overloads of the 
    // shadowed method can be called.
    //
    Console::WriteLine(
        "------ Call the shadowed overloads of PrintCall ------");
    Parent^ parentInstance = childInstance;
    parentInstance->PrintCall();
    parentInstance->PrintCall(42);
}

/* This code example produces the following output:

------ List the overloads of PrintCall in the derived class Child ------
Overload of PrintCall: Void PrintCall(Int32) IsHideBySig = True, DeclaringType = Child
Overload of PrintCall: Void PrintCall() IsHideBySig = True, DeclaringType = Parent
Overload of PrintCall: Void PrintCall(Int32) IsHideBySig = True, DeclaringType = Parent
------ Call the overloads of PrintCall available in Child ------
Parent's PrintCall()
Child's PrintCall(42)
------ Call the shadowed overloads of PrintCall ------
Parent's PrintCall()
Parent's PrintCall(42)

*/

import System.*;
import System.Reflection.*;

// The base class B contains an overloaded method M.
//
public class B
{
    public void M()
    {
        Console.WriteLine("B's M()");
    } //M

    public void M(int x)
    {
        Console.WriteLine("B's M({0})", (Int32)x);
    } //M
} //B

// The derived class D hides one overload of the inherited 
// method M.
//
public class D extends B
{
    public void M(int i)
    {
        Console.WriteLine("D's M({0})", (Int32)i);
    } //M
} //D

public class Test
{
    public static void main(String[] args)
    {
        D dInst = new D();
        // In VJ#, the method in the derived class hides by name and by
        // signature, so the overload in the derived class hides only one
        // of the overloads in the base class.
        //
        Console.WriteLine("------ List the overloads of M in the "
            + "derived class D ------");
        Type t = dInst.GetType();
        for (int iCtr = 0; iCtr < t.GetMethods().get_Length(); iCtr++) {
            MethodInfo mInfo = (MethodInfo)t.GetMethods().get_Item(iCtr);
            if (mInfo.get_Name().Equals("M")) {
                Console.WriteLine("Overload of M: {0}  IsHideBySig = {1}, "
                    + "DeclaringType = {2}", mInfo, 
                    (System.Boolean)mInfo.get_IsHideBySig(), 
                    mInfo.get_DeclaringType().ToString());
            }
        }
        // The method M in the derived class hides one overload of the 
        // method in B.  Contrast this with Visual Basic, which hides by
        // name instead of by name and signature.  In Visual Basic, the
        // parameterless overload of M would be unavailable from D.
        //
        Console.WriteLine("------ Call the overloads of M available in D ------");
        dInst.M();
        dInst.M(42);
        // If D is cast to the base type B, both overloads of the 
        // shadowed method can be called.
        //
        Console.WriteLine("------ Call the shadowed overloads of M ------");
        B bInst = dInst;
        bInst.M();
        bInst.M(42);
    } //main 
} //Test
/* This code example produces the following output:

------ List the overloads of M in the derived class D ------
Overload of M: Void M(Int32)  IsHideBySig = True, DeclaringType = D
Overload of M: Void M()  IsHideBySig = True, DeclaringType = B
------ Call the overloads of M available in D ------
B's M()
D's M(42)
------ Call the shadowed overloads of M ------
B's M()
D's M(42)

*/

Plattformen

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile für Pocket PC, Windows Mobile für Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.

Freigeben über

MethodBase.IsHideBySig-Eigenschaft

Syntax

Eigenschaftenwert

Hinweise

Beispiel

Plattformen

Versionsinformationen

.NET Framework

.NET Compact Framework

Siehe auch

Referenz

Zusätzliche Ressourcen