ValueType Klasse

Definition

public ref class ValueType abstract

public abstract class ValueType

[System.Serializable]
public abstract class ValueType

[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public abstract class ValueType

type ValueType = class

[<System.Serializable>]
type ValueType = class

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

Public MustInherit Class ValueType

Vererbung

Object

ValueType

Abgeleitet

_GUID

Accessibility.__MIDL_IWinTypes_0009

Accessibility._RemotableHandle

IStream

ISymUnmanagedBinder

Mehr …

Attribute

SerializableAttribute ComVisibleAttribute

Hinweise

ValueType überschreibt die virtuellen Methoden aus Object mit geeigneteren Implementierungen für Werttypen.ValueType overrides the virtual methods from Object with more appropriate implementations for value types. Siehe auch Enum , das von erbt ValueType .See also Enum, which inherits from ValueType.

Datentypen werden in Werttypen und Verweis Typen unterteilt.Data types are separated into value types and reference types. Werttypen werden entweder in einem Stapel zugeordnet oder Inline in einer Struktur zugeordnet.Value types are either stack-allocated or allocated inline in a structure. Verweis Typen werden Heap zugeordnet.Reference types are heap-allocated. Verweis-und Werttypen werden von der Ultimate-Basisklasse abgeleitet Object .Both reference and value types are derived from the ultimate base class Object. In Fällen, in denen es erforderlich ist, dass sich ein Werttyp wie ein Objekt verhält, wird ein Wrapper, der den Werttyp als Verweis Objekt ausgleicht, auf dem Heap zugeordnet, und der Wert des Werttyps wird in ihn kopiert.In cases where it is necessary for a value type to behave like an object, a wrapper that makes the value type look like a reference object is allocated on the heap, and the value type's value is copied into it. Der Wrapper ist so gekennzeichnet, dass das System weiß, dass es einen Werttyp enthält.The wrapper is marked so the system knows that it contains a value type. Dieser Prozess wird als Boxing bezeichnet, und der umgekehrte Prozess wird als Unboxing bezeichnet.This process is known as boxing, and the reverse process is known as unboxing. Beim Boxing und Unboxing kann jeder Typ als Objekt behandelt werden.Boxing and unboxing allow any type to be treated as an object.

Obwohl ValueType die implizite Basisklasse für Werttypen ist, können Sie keine Klasse erstellen, die direkt von erbt ValueType .Although ValueType is the implicit base class for value types, you cannot create a class that inherits from ValueType directly. Stattdessen stellen einzelne Compiler ein sprach Schlüsselwort oder Konstrukt bereit (z struct . b. in c# und Structure ...End StructureInstead, individual compilers provide a language keyword or construct (such as struct in C# and Structure…End Structure in Visual Basic), um die Erstellung von Werttypen zu unterstützen.in Visual Basic) to support the creation of value types.

Abgesehen von der Bereitstellung als Basisklasse für Werttypen im .NET Framework wird die Struktur in der ValueType Regel nicht direkt im Code verwendet.Aside from serving as the base class for value types in the .NET Framework, the ValueType structure is generally not used directly in code. Sie kann jedoch als Parameter in Methoden aufrufen verwendet werden, um mögliche Argumente auf Werttypen anstelle von allen Objekten zu beschränken, oder um eine Methode für die Verarbeitung einer Reihe unterschiedlicher Werttypen zuzulassen.However, it can be used as a parameter in method calls to restrict possible arguments to value types instead of all objects, or to permit a method to handle a number of different value types. Im folgenden Beispiel wird veranschaulicht ValueType , wie die Übergabe von Verweis Typen an-Methoden verhindert.The following example illustrates how ValueType prevents reference types from being passed to methods. Er definiert eine Klasse mit dem Namen Utility , die vier Methoden enthält: IsNumeric , die angibt, ob das Argument eine Zahl ist, IsInteger , gibt an, ob das Argument eine ganze Zahl ist,, gibt an, ob das Argument eine Gleit IsFloat Komma Zahl ist, und gibt Compare die Beziehung zwischen zwei numerischen Werten an.It defines a class named Utility that contains four methods: IsNumeric, which indicates whether its argument is a number; IsInteger, which indicates whether its argument is an integer; IsFloat, which indicates whether its argument is a floating-point number; and Compare, which indicates the relationship between two numeric values. In jedem Fall sind die Methoden Parameter vom Typ ValueType , und die Übergabe von Verweis Typen an die Methoden wird verhindert.In each case, the method parameters are of type ValueType, and reference types are prevented from being passed to the methods.

using System;
using System.Numerics;

public class Utility
{
   public enum NumericRelationship {
      GreaterThan = 1, 
      EqualTo = 0,
      LessThan = -1
   };
   
   public static NumericRelationship Compare(ValueType value1, ValueType value2)
   {
      if (! IsNumeric(value1)) 
         throw new ArgumentException("value1 is not a number.");
      else if (! IsNumeric(value2))
         throw new ArgumentException("value2 is not a number.");

      // Use BigInteger as common integral type
      if (IsInteger(value1) && IsInteger(value2)) {
         BigInteger bigint1 = (BigInteger) value1;
         BigInteger bigint2 = (BigInteger) value2;
         return (NumericRelationship) BigInteger.Compare(bigint1, bigint2);
      }
      // At least one value is floating point; use Double.
      else {
         Double dbl1 = 0;
         Double dbl2 = 0;
         try {
            dbl1 = Convert.ToDouble(value1);
         }
         catch (OverflowException) {
            Console.WriteLine("value1 is outside the range of a Double.");
         }
         try {
            dbl2 = Convert.ToDouble(value2);
         }
         catch (OverflowException) {
            Console.WriteLine("value2 is outside the range of a Double.");
         }
         return (NumericRelationship) dbl1.CompareTo(dbl2);
      }
   }
   
   public static bool IsInteger(ValueType value)
   {         
      return (value is SByte || value is Int16 || value is Int32 
              || value is Int64 || value is Byte || value is UInt16  
              || value is UInt32 || value is UInt64 
              || value is BigInteger); 
   }

   public static bool IsFloat(ValueType value) 
   {         
      return (value is float | value is double | value is Decimal);
   }

   public static bool IsNumeric(ValueType value)
   {
      return (value is Byte ||
              value is Int16 ||
              value is Int32 ||
              value is Int64 ||
              value is SByte ||
              value is UInt16 ||
              value is UInt32 ||
              value is UInt64 ||
              value is BigInteger ||
              value is Decimal ||
              value is Double ||
              value is Single);
   }
}

Imports System.Numerics

Public Class Utility
   Public Enum NumericRelationship As Integer
      GreaterThan = 1
      EqualTo = 0
      LessThan = -1
   End Enum
      
   Public Shared Function Compare(value1 As ValueType, value2 As ValueType) _
                                  As NumericRelationship
      If Not IsNumeric(value1) Then 
         Throw New ArgumentException("value1 is not a number.")
      Else If Not IsNumeric(value2) Then
         Throw New ArgumentException("value2 is not a number.")
      Else
         ' Use BigInteger as common integral type
         If isInteger(value1) And IsInteger(value2) Then
            Dim bigint1 As BigInteger = CType(value1, BigInteger)
            Dim bigInt2 As BigInteger = CType(value2, BigInteger)
            Return CType(BigInteger.Compare(bigint1, bigint2), NumericRelationship)
         ' At least one value is floating point; use Double.
         Else   
            Dim dbl1, dbl2 As Double
            Try
               dbl1 = CDbl(value1)
            Catch e As OverflowException
               Console.WriteLine("value1 is outside the range of a Double.")
            End Try
               
            Try
               dbl2 = CDbl(value2)
            Catch e As OverflowException
               Console.WriteLine("value2 is outside the range of a Double.")
            End Try
            Return CType(dbl1.CompareTo(dbl2), NumericRelationship)
         End If
      End If
   End Function
   
   Public Shared Function IsInteger(value As ValueType) As Boolean         
      Return (TypeOf value Is SByte Or TypeOf value Is Int16 Or TypeOf value Is Int32 _
                 Or TypeOf value Is Int64 Or TypeOf value Is Byte Or TypeOf value Is UInt16 _ 
                 Or TypeOf value Is UInt32 Or TypeOf value Is UInt64 _
                 Or TypeOf value Is BigInteger) 
   End Function

   Public Shared Function IsFloat(value As ValueType) As Boolean         
      Return (TypeOf value Is Single Or TypeOf value Is Double Or TypeOf value Is Decimal)
   End Function

   Public Shared Function IsNumeric(value As ValueType) As Boolean
      Return TypeOf value Is Byte OrElse
         TypeOf value Is Int16 OrElse
         TypeOf value Is Int32 OrElse
         TypeOf value Is Int64 OrElse
         TypeOf value Is SByte OrElse
         TypeOf value Is UInt16 OrElse
         TypeOf value Is UInt32 OrElse
         TypeOf value Is UInt64 OrElse
         TypeOf value Is BigInteger OrElse
         TypeOf value Is Decimal OrElse
         TypeOf value Is Double OrElse
         TypeOf value Is Single
   End Function
End Class

Das folgende Beispiel veranschaulicht Aufrufe der-Methoden der- Utility Klasse.The following example illustrates calls to the methods of the Utility class.

public class Example
{
   public static void Main()
   {
      Console.WriteLine(Utility.IsNumeric(12));
      Console.WriteLine(Utility.IsNumeric(true));
      Console.WriteLine(Utility.IsNumeric('c'));
      Console.WriteLine(Utility.IsNumeric(new DateTime(2012, 1, 1)));
      Console.WriteLine(Utility.IsInteger(12.2));
      Console.WriteLine(Utility.IsInteger(123456789));
      Console.WriteLine(Utility.IsFloat(true));
      Console.WriteLine(Utility.IsFloat(12.2));
      Console.WriteLine(Utility.IsFloat(12));
      Console.WriteLine("{0} {1} {2}", 12.1, Utility.Compare(12.1, 12), 12);
   }
}
// The example displays the following output:
//       True
//       False
//       False
//       False
//       False
//       True
//       False
//       True
//       False
//       12.1 GreaterThan 12

Module Example
   Public Sub Main()
      Console.WriteLine(Utility.IsNumeric(12))
      Console.WriteLine(Utility.IsNumeric(True))
      Console.WriteLine(Utility.IsNumeric("c"c))
      Console.WriteLine(Utility.IsNumeric(#01/01/2012#))
      Console.WriteLine(Utility.IsInteger(12.2))
      Console.WriteLine(Utility.IsInteger(123456789))
      Console.WriteLine(Utility.IsFloat(True))
      Console.WriteLine(Utility.IsFloat(12.2))
      Console.WriteLine(Utility.IsFloat(12))
      Console.WriteLine("{0} {1} {2}", 12.1, Utility.Compare(12.1, 12), 12)
   End Sub
End Module
' The example displays the following output:
'       True
'       False
'       False
'       False
'       False
'       True
'       False
'       True
'       False
'       12.1 GreaterThan 12

Konstruktoren

Methoden

Gilt für:

Siehe auch

• Object
• Enum