Type.IsExplicitLayout 属性


获取指示当前类型的字段是否放置在显式指定的偏移量处的值。Gets a value indicating whether the fields of the current type are laid out at explicitly specified offsets.

 property bool IsExplicitLayout { bool get(); };
public bool IsExplicitLayout { get; }
member this.IsExplicitLayout : bool
Public ReadOnly Property IsExplicitLayout As Boolean


如果当前类型的 true 属性包括 Attributes,则为 ExplicitLayout;否则为 falsetrue if the Attributes property of the current type includes ExplicitLayout; otherwise, false.



下面的示例创建一个类型的实例,并显示其 IsExplicitLayout 属性的值。The following example creates an instance of a type and displays the value of its IsExplicitLayout property. 它使用 MySystemTime 类,该类也在 StructLayoutAttribute的代码示例中。It uses the MySystemTime class, which is also in the code example for StructLayoutAttribute.

using System;
using System.Reflection;
using System.ComponentModel;
using System.Runtime.InteropServices;

// Class to test for the ExplicitLayout property.
[StructLayout(LayoutKind.Explicit, Size=16, CharSet=CharSet.Ansi)]
public class MySystemTime
   [FieldOffset(0)]public ushort wYear;
   [FieldOffset(2)]public ushort wMonth;
   [FieldOffset(4)]public ushort wDayOfWeek;
   [FieldOffset(6)]public ushort wDay;
   [FieldOffset(8)]public ushort wHour;
   [FieldOffset(10)]public ushort wMinute;
   [FieldOffset(12)]public ushort wSecond;
   [FieldOffset(14)]public ushort wMilliseconds;

public class Program
    public static void Main(string[] args)
        // Create an instance of the type using the GetType method.
        Type  t = typeof(MySystemTime);
        // Get and display the IsExplicitLayout property.
        Console.WriteLine("\nIsExplicitLayout for MySystemTime is {0}.",
Imports System.Reflection
Imports System.ComponentModel
Imports System.Runtime.InteropServices

'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}.", _
    End Sub
End Class


提供此属性是为了方便。This property is provided as a convenience. 或者,您可以使用 TypeAttributes.LayoutMask 的枚举值选择类型布局特性,然后测试是否设置了 TypeAttributes.ExplicitLayoutAlternatively, you can use the TypeAttributes.LayoutMask enumeration value to select the type layout attributes, and then test whether TypeAttributes.ExplicitLayout is set. TypeAttributes.AutoLayoutTypeAttributes.ExplicitLayoutTypeAttributes.SequentialLayout 枚举值指示类型的字段在内存中的布局方式。The TypeAttributes.AutoLayout, TypeAttributes.ExplicitLayout, and TypeAttributes.SequentialLayout enumeration values indicate the way the fields of the type are laid out in memory.

对于动态类型,可以在创建类型时指定 TypeAttributes.ExplicitLayoutFor dynamic types, you can specify TypeAttributes.ExplicitLayout when you create the type. 在代码中,将具有 LayoutKind.Explicit 枚举值的 StructLayoutAttribute 特性应用到类型,以指定显式指定字段开始的偏移量。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.


不能使用 GetCustomAttributes 方法来确定 StructLayoutAttribute 是否已应用于类型。You cannot use the GetCustomAttributes method to determine whether the StructLayoutAttribute has been applied to a type.

如果当前 Type 表示构造泛型类型,则此属性应用于构造该类型的泛型类型定义。If the current Type represents a constructed generic type, this property applies to the generic type definition from which the type was constructed. 例如,如果当前 Type 表示 MyGenericType<int>MyGenericType(Of Integer) Visual Basic),则此属性的值由 MyGenericType<T>确定。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>.

如果当前 Type 表示泛型类型或泛型方法的定义中的类型参数,则此属性始终返回 falseIf the current Type represents a type parameter in the definition of a generic type or generic method, this property always returns false.