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,该类也在的代码StructLayoutAttribute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枚举值选择类型布局特性,然后测试是否TypeAttributes.ExplicitLayout已设置。Alternatively, you can use the TypeAttributes.LayoutMask enumeration value to select the type layout attributes, and then test whether TypeAttributes.ExplicitLayout is set. TypeAttributes.AutoLayout、和枚举TypeAttributes.SequentialLayout值指示类型的字段在内存中的布局方式。 TypeAttributes.ExplicitLayoutThe 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TypeAttributes.ExplicitLayout类型时指定。For dynamic types, you can specify TypeAttributes.ExplicitLayout when you create the type. 在代码中,将StructLayoutAttribute LayoutKind.Explicit具有枚举值的属性应用到类型,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Type当前表示MyGenericType<int>MyGenericType(Of Integer)在 Visual Basic 中),则此属性的值由确定MyGenericType<T>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.