LayoutKind LayoutKind LayoutKind LayoutKind Enum

Definición

Controla el diseño de un objeto cuando se exporta a código no administrado.Controls the layout of an object when exported to unmanaged code.

public enum class LayoutKind
[System.Runtime.InteropServices.ComVisible(true)]
[System.Serializable]
public enum LayoutKind
type LayoutKind = 
Public Enum LayoutKind
Herencia
Atributos

Campos

Auto Auto Auto Auto 3

El motor en tiempo de ejecución elige un diseño apropiado para los miembros de un objeto en la memoria no administrada.The runtime automatically chooses an appropriate layout for the members of an object in unmanaged memory. Los objetos definidos con este miembro de enumeración no se pueden exponer fuera del código administrado.Objects defined with this enumeration member cannot be exposed outside of managed code. Si se intenta hacer esto, se genera una excepción.Attempting to do so generates an exception.

Explicit Explicit Explicit Explicit 2

La posición exacta de cada miembro de un objeto en memoria no administrada se controla explícitamente, sujeta al valor del campo Pack.The precise position of each member of an object in unmanaged memory is explicitly controlled, subject to the setting of the Pack field. Cada miembro debe utilizar FieldOffsetAttribute para indicar la posición del campo dentro del tipo.Each member must use the FieldOffsetAttribute to indicate the position of that field within the type.

Sequential Sequential Sequential Sequential 0

Los miembros del objeto se disponen secuencialmente, en el orden en que aparecen cuando se exporta a la memoria no administrada.The members of the object are laid out sequentially, in the order in which they appear when exported to unmanaged memory. Los miembros se disponen de acuerdo con el empaquetado especificado en Pack y pueden no ser contiguos.The members are laid out according to the packing specified in Pack, and can be noncontiguous.

Ejemplos

En el ejemplo siguiente se muestra la declaración administrada de la PtInRect función, que comprueba si un punto está dentro de un rectángulo y define una Point estructura con diseño Rect secuencial y una estructura con diseño explícito.The following example shows the managed declaration of the PtInRect function, which checks whether a point lies within a rectangle, and defines a Point structure with Sequential layout and a Rect structure with Explicit layout.

enum class Bool
{
   False = 0,
   True
};


[StructLayout(LayoutKind::Sequential)]
value struct Point
{
public:
   int x;
   int y;
};


[StructLayout(LayoutKind::Explicit)]
value struct Rect
{
public:

   [FieldOffset(0)]
   int left;

   [FieldOffset(4)]
   int top;

   [FieldOffset(8)]
   int right;

   [FieldOffset(12)]
   int bottom;
};

ref class NativeMethods
{
public:

   [DllImport("user32.dll",CallingConvention=CallingConvention::StdCall)]
   static Bool PtInRect( Rect * r, Point p );
};

int main()
{
   try
   {
      Bool bPointInRect = (Bool)0;
      Rect myRect = Rect(  );
      myRect.left = 10;
      myRect.right = 100;
      myRect.top = 10;
      myRect.bottom = 100;
      Point myPoint = Point(  );
      myPoint.x = 50;
      myPoint.y = 50;
      bPointInRect = NativeMethods::PtInRect(  &myRect, myPoint );
      if ( bPointInRect == Bool::True )
            Console::WriteLine( "Point lies within the Rect" );
      else
            Console::WriteLine( "Point did not lie within the Rect" );
   }
   catch ( Exception^ e ) 
   {
      Console::WriteLine( "Exception : {0}", e->Message );
   }

}

enum Bool
{
   False = 0,
   True
};
[StructLayout(LayoutKind.Sequential)]
public struct Point 
{
   public int x;
   public int y;
}   

[StructLayout(LayoutKind.Explicit)]
public struct Rect 
{
   [FieldOffset(0)] public int left;
   [FieldOffset(4)] public int top;
   [FieldOffset(8)] public int right;
   [FieldOffset(12)] public int bottom;
}   

internal static class NativeMethods
{
   [DllImport("user32.dll", CallingConvention=CallingConvention.StdCall)]
   internal static extern Bool PtInRect(ref Rect r, Point p);
};

class TestApplication
{
   public static void Main()
   {
      try
      {
         Bool bPointInRect = 0;
         Rect myRect = new Rect();
         myRect.left = 10;
         myRect.right = 100;
         myRect.top = 10;
         myRect.bottom = 100;
         Point myPoint = new Point();
         myPoint.x = 50;
         myPoint.y = 50;
         bPointInRect = NativeMethods.PtInRect(ref myRect, myPoint);
         if(bPointInRect == Bool.True)
            Console.WriteLine("Point lies within the Rect");
         else
            Console.WriteLine("Point did not lie within the Rect");
      }
      catch(Exception e)
      {
         Console.WriteLine("Exception : " + e.Message);
      }
   }
}
'  The program shows a managed declaration of the PtInRect function and defines Point
'  structure with sequential layout and Rect structure with explicit layout. The PtInRect
'  checks the point lies within the rectangle or not.
Imports System.Runtime.InteropServices

   Enum Bool
      [False] = 0
      [True]
   End Enum 
   <StructLayout(LayoutKind.Sequential)>  _
   Public Structure Point
      Public x As Integer
      Public y As Integer
   End Structure 
   
   <StructLayout(LayoutKind.Explicit)>  _   
   Public Structure Rect
      <FieldOffset(0)> Public left As Integer
      <FieldOffset(4)> Public top As Integer
      <FieldOffset(8)> Public right As Integer
      <FieldOffset(12)> Public bottom As Integer
   End Structure 
   
   
   Friend Class NativeMethods
      
      <DllImport("user32.dll", CallingConvention := CallingConvention.StdCall)>  _
      Friend Shared Function PtInRect(ByRef r As Rect, p As Point) As Bool
      End Function	
   End Class
   
   
   Class TestApplication
      
      Public Shared Sub Main()
         Try
            Dim bPointInRect As Bool = 0
            Dim myRect As New Rect()
            myRect.left = 10
            myRect.right = 100
            myRect.top = 10
            myRect.bottom = 100
            Dim myPoint As New Point()
            myPoint.x = 50
            myPoint.y = 50
            bPointInRect = NativeMethods.PtInRect(myRect, myPoint)
            If bPointInRect = Bool.True Then
               Console.WriteLine("Point lies within the Rect")
            Else
               Console.WriteLine("Point did not lie within the Rect")
            End If
         Catch e As Exception
            Console.WriteLine(("Exception : " + e.Message.ToString()))
         End Try
      End Sub 
   End Class 

Comentarios

Esta enumeración se utiliza StructLayoutAttributecon.This enumeration is used with StructLayoutAttribute. De forma predeterminada, Auto el Common Language Runtime utiliza el valor de diseño.The common language runtime uses the Auto layout value by default. Para reducir los problemas relacionados con el diseño asociados Auto al valor C#,, Visual Basic y C++ los compiladores Sequential especifican el diseño de los tipos de valor.To reduce layout-related problems associated with the Auto value, C#, Visual Basic, and C++ compilers specify Sequential layout for value types.

Importante

El StructLayoutAttribute.Pack campo controla la alineación de los campos de datos y, por tanto, afecta al LayoutKind diseño, independientemente del valor que se especifique.The StructLayoutAttribute.Pack field controls the alignment of data fields, and thus affects the layout regardless of the LayoutKind value you specify. De forma predeterminada, el valor Pack de es 0, que indica el tamaño de empaquetado predeterminado para la plataforma actual.By default, the value of Pack is 0, which indicates the default packing size for the current platform. Por ejemplo, si usa el Explicit valor de diseño y especifica las alineaciones de campo en los límites de bytes, debe establecer Pack en 1 para obtener el resultado deseado.For example, when you use the Explicit layout value and specify field alignments on byte boundaries, you must set Pack to 1 to get the desired result.

Se aplica a