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MethodBase.IsHideBySig Property

Gets a value indicating whether only a member of the same kind with exactly the same signature is hidden in the derived class.

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

public bool IsHideBySig { get; }

Property Value

Type: System.Boolean
true if the member is hidden by signature; otherwise, false.

When a member in a derived class is declared with the C# new modifier or the Visual Basic Shadows modifier, it can hide a member of the same name in the base class. C# hides base class members by signature. That is, if the base class member has multiple overloads, the only one that is hidden is the one that has the identical signature. By contrast, Visual Basic hides all the base class overloads. Thus, IsHideBySig returns false on a member declared with the Visual Basic Shadows modifier, and true on a member declared with the C# new modifier.

Caution noteCaution

This property does not determine whether a method has the NewSlot attribute. A method that is declared with either the new or the Shadows modifier will have the NewSlot attribute, but only methods declared with new (that is, only C# methods) will have the IsHideBySig property set to true. To determine whether a method has the NewSlot attribute, use code similar to the following: if ((myMethodInfo.Attributes & MethodAttributes.VtableLayoutMask) == MethodAttributes.NewSlot) in C# or If (myMethodInfo.Attributes And MethodAttributes.VtableLayoutMask) = MethodAttributes.NewSlot in Visual Basic. Note, however, that although all methods declared with new or Shadows have the NewSlot attribute, not all methods that have the NewSlot attribute are declared with new or Shadows.

The following code example contains a base class with an overloaded method, and a derived class that hides one of the overloads. In the Visual Basic version of the code example, the IsHideBySig property returns false for the member in the derived class. In the C# version of the code sample, the property returns true for the member in the derived class.


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)
*/



.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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