Missing Class

Definition

public ref class Missing sealed

public ref class Missing sealed : System::Runtime::Serialization::ISerializable

public sealed class Missing

public sealed class Missing : System.Runtime.Serialization.ISerializable

[System.Runtime.InteropServices.ComVisible(true)]
[System.Serializable]
public sealed class Missing : System.Runtime.Serialization.ISerializable

type Missing = class

type Missing = class
    interface ISerializable

[<System.Runtime.InteropServices.ComVisible(true)>]
[<System.Serializable>]
type Missing = class
    interface ISerializable

Public NotInheritable Class Missing

Public NotInheritable Class Missing
Implements ISerializable

Inheritance

Object

Missing

Attributes

ComVisibleAttribute SerializableAttribute

Implements

ISerializable

Examples

The following example shows how to use the Missing object to invoke a method with a default argument by using reflection.

using System;
using System.Reflection;

[assembly:CLSCompliant(true)]

public class MissingClass
{
   public static void MethodWithDefault(int value = 33)
   {
      Console.WriteLine("value = {0}", value);
   } 
}

public class Example
{
   public static void Main()
   {
      // Invoke without reflection
      MissingClass.MethodWithDefault();
      
      // Invoke by using reflection.
      Type t = typeof(MissingClass);
      MethodInfo mi = t.GetMethod("MethodWithDefault");
      mi.Invoke(null, new object[] { Missing.Value });
   }
}
// The example displays the following output:
//       value = 33  
//       value = 33

Imports System.Reflection

<Assembly:CLSCompliant(True)>

Public Class MissingClass
   Public Shared Sub MethodWithDefault(Optional value As Integer = 33)
      Console.WriteLine("value = {0}", value)
   End Sub 
End Class   

Public Module Example
   Public Sub Main()
      ' Invoke without reflection.
      MissingClass.MethodWithDefault()
      
      ' Invoke by using reflection.
      Dim t As Type = GetType(MissingClass)
      Dim mi As MethodInfo = t.GetMethod("MethodWithDefault")
      mi.Invoke(Nothing, { Missing.Value })
   End Sub
End Module
' The example displays the following output:
'       value = 33 
'       value = 33

Remarks

The Missing class is used to invoke a method with a default argument, typically when using reflection.

Only one instance of Missing, which is returned by the Value field, ever exists.

See also

• DBNull