Export (0) Print
Expand All
Expand Minimize

Type.IsExplicitLayout Property

Gets a value indicating whether the fields of the current type are laid out at explicitly specified offsets.

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

'Declaration
Public ReadOnly Property IsExplicitLayout As Boolean

Property Value

Type: System.Boolean
true if the Attributes property of the current type includes TypeAttributes.ExplicitLayout; otherwise, false.

Implements

_Type.IsExplicitLayout

This property is provided as a convenience. Alternatively, you can use the TypeAttributes.LayoutMask enumeration value to select the type layout attributes, and then test whether TypeAttributes.ExplicitLayout is set. The TypeAttributes.AutoLayout, TypeAttributes.ExplicitLayout, and TypeAttributes.SequentialLayout enumeration values indicate the way the fields of the type are laid out in memory.

For dynamic types, you can specify TypeAttributes.ExplicitLayout when you create the type. In code, apply the StructLayoutAttribute attribute with the LayoutKind.Explicit enumeration value to the type, to specify that the offsets at which the fields start are specified explicitly.

NoteNote

You cannot use the GetCustomAttributes method to determine whether the StructLayoutAttribute has been applied to a type.

If the current Type represents a constructed generic type, this property applies to the generic type definition from which the type was constructed. For example, if the current Type represents MyGenericType<int> (MyGenericType(Of Integer) in Visual Basic), the value of this property is determined by MyGenericType<T>.

If the current Type represents a type parameter in the definition of a generic type or generic method, this property always returns false.

The following example creates an instance of a type and displays the value of its IsExplicitLayout property. It uses the MySystemTime class, which is also in the code example for StructLayoutAttribute.

Imports System
Imports System.Reflection
Imports System.ComponentModel
Imports System.Runtime.InteropServices
Imports Microsoft.VisualBasic

'Class to test for the ExplicitLayout property.
   <StructLayout(LayoutKind.Explicit, Size := 16, CharSet := CharSet.Ansi)>  _
   Public Class MySystemTime
      <FieldOffset(0)> Public wYear As Short
      <FieldOffset(2)> Public wMonth As Short
      <FieldOffset(4)> Public wDayOfWeek As Short
      <FieldOffset(6)> Public wDay As Short
      <FieldOffset(8)> Public wHour As Short
      <FieldOffset(10)> Public wMinute As Short
      <FieldOffset(12)> Public wSecond As Short
      <FieldOffset(14)> Public wMilliseconds As Short 
   End Class  

Public Class Program
    Public Shared Sub Main()
        'Create an instance of type using the GetType method. 
        Dim t As Type = GetType(MySystemTime)
        ' Get and display the IsExplicitLayout property.
        Console.WriteLine(vbCrLf & "IsExplicitLayout for MySystemTime is {0}.", _
            t.IsExplicitLayout)
    End Sub 
End Class

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

Show:
© 2014 Microsoft