Type.IsLayoutSequential Property

Definition

Namespace:

System

Assembly:

System.Runtime.dll

Source:

Type.cs

Gets a value indicating whether the fields of the current type are laid out sequentially, in the order that they were defined or emitted to the metadata.

public:
 property bool IsLayoutSequential { bool get(); };

public bool IsLayoutSequential { get; }

member this.IsLayoutSequential : bool

Public ReadOnly Property IsLayoutSequential As Boolean

Property Value

Boolean

true if the Attributes property of the current type includes SequentialLayout; otherwise, false.

Examples

The following example creates an instance of a class for which the LayoutKind.Sequential enumeration value in the StructLayoutAttribute class has been set, checks for the IsLayoutSequential property, and displays the result.

#using <System.dll>

using namespace System;
using namespace System::Reflection;
using namespace System::ComponentModel;
using namespace System::Runtime::InteropServices;
ref class MyTypeSequential1{};


[StructLayoutAttribute(LayoutKind::Sequential)]
ref class MyTypeSequential2{};

int main()
{
   try
   {
      
      // Create an instance of myTypeSeq1.
      MyTypeSequential1^ myObj1 = gcnew MyTypeSequential1;
      
      // Check for and display the SequentialLayout attribute.
      Console::WriteLine( "\nThe object myObj1 has IsLayoutSequential: {0}.", myObj1->GetType()->IsLayoutSequential );
      
      // Create an instance of 'myTypeSeq2' class.
      MyTypeSequential2^ myObj2 = gcnew MyTypeSequential2;
      
      // Check for and display the SequentialLayout attribute.
      Console::WriteLine( "\nThe object myObj2 has IsLayoutSequential: {0}.", myObj2->GetType()->IsLayoutSequential );
   }
   catch ( Exception^ e ) 
   {
      Console::WriteLine( "\nAn exception occurred: {0}", e->Message );
   }

}

using System;
using System.Reflection;
using System.ComponentModel;
using System.Runtime.InteropServices;
class MyTypeSequential1
{
}
[StructLayoutAttribute(LayoutKind.Sequential)]
class MyTypeSequential2
{
    public static void Main(string []args)
    {
        try
        {
            // Create an instance of myTypeSeq1.
            MyTypeSequential1 myObj1 = new MyTypeSequential1();
            Type myTypeObj1 = myObj1.GetType();
            // Check for and display the SequentialLayout attribute.
            Console.WriteLine("\nThe object myObj1 has IsLayoutSequential: {0}.", myObj1.GetType().IsLayoutSequential);
            // Create an instance of 'myTypeSeq2' class.
            MyTypeSequential2 myObj2 = new MyTypeSequential2();
            Type myTypeObj2 = myObj2.GetType();
            // Check for and display the SequentialLayout attribute.
            Console.WriteLine("\nThe object myObj2 has IsLayoutSequential: {0}.", myObj2.GetType().IsLayoutSequential);
        }
        catch(Exception e)
        {
            Console.WriteLine("\nAn exception occurred: {0}", e.Message);
        }
    }
}

open System.Runtime.InteropServices

type MyTypeSequential1 = struct end

[<StructLayoutAttribute(LayoutKind.Sequential)>]
type MyTypeSequential2 = struct end

try
    // Create an instance of myTypeSeq1.
    let myObj1 = MyTypeSequential1()
    let myTypeObj1 = myObj1.GetType()
    // Check for and display the SequentialLayout attribute.
    printfn $"\nThe object myObj1 has IsLayoutSequential: {myTypeObj1.IsLayoutSequential}."
    // Create an instance of 'myTypeSeq2' class.
    let myObj2 = MyTypeSequential2()
    let myTypeObj2 = myObj2.GetType()
    // Check for and display the SequentialLayout attribute.
    printfn $"\nThe object myObj2 has IsLayoutSequential: {myTypeObj2.IsLayoutSequential}."
with e ->
    printfn $"\nAn exception occurred: {e.Message}"

Imports System.Reflection
Imports System.ComponentModel
Imports System.Runtime.InteropServices

Class MyTypeSequential1
End Class
<StructLayoutAttribute(LayoutKind.Sequential)> Class MyTypeSequential2
    Public Shared Sub Main()
        Try
            ' Create an instance of MyTypeSequential1.
            Dim myObj1 As New MyTypeSequential1()
            Dim myTypeObj1 As Type = myObj1.GetType()
            ' Check for and display the SequentialLayout attribute.
            Console.WriteLine(ControlChars.Cr + "The object myObj1 has IsLayoutSequential: {0}.", myObj1.GetType().IsLayoutSequential.ToString())
            ' Create an instance of MyTypeSequential2.
            Dim myObj2 As New MyTypeSequential2()
            Dim myTypeObj2 As Type = myObj2.GetType()
            ' Check for and display the SequentialLayout attribute.
            Console.WriteLine(ControlChars.Cr + "The object myObj2 has IsLayoutSequential: {0}.", myObj2.GetType().IsLayoutSequential.ToString())
        Catch e As Exception
            Console.WriteLine(ControlChars.Cr + "An exception occurred: {0}", e.Message.ToString())
        End Try
    End Sub
End Class

Remarks

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.SequentialLayout 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.SequentialLayout when you create the type. In code, apply the StructLayoutAttribute attribute with the LayoutKind.Sequential enumeration value to the type, to specify that layout is sequential.

Note

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

For more information, see section 9.1.2 of the specification for the Common Language Infrastructure (CLI) documentation, "Partition II: Metadata Definition and Semantics".

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.

See also

• TypeAttributes
• IsAutoLayout
• IsExplicitLayout
• Metadata and Self-Describing Components