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)

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.

This property is provided as a convenience. Alternatively, you can use the TypeAttributes.LayoutMaskenumeration 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.

System_CAPS_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
Available since 1.1
Windows Phone Silverlight
Available since 8.0
Return to top
Show: