Lets you control the physical layout of the data fields of a class or structure in memory.
Assemblies: System.Runtime (in System.Runtime.dll)
mscorlib (in mscorlib.dll)
Thetype exposes the following members.
|StructLayoutAttribute(Int16)||Initalizes a new instance of the class with the specified System.Runtime.InteropServices.LayoutKind enumeration member.|
|StructLayoutAttribute(LayoutKind)||Initalizes a new instance of the class with the specified System.Runtime.InteropServices.LayoutKind enumeration member.|
|Equals||Infrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)|
|GetHashCode||Returns the hash code for this instance. (Inherited from Attribute.)|
|GetType||Gets the Type of the current instance. (Inherited from Object.)|
|IsDefaultAttribute||When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)|
|Match||When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)|
|ToString||Returns a string that represents the current object. (Inherited from Object.)|
|_Attribute.GetIDsOfNames||Maps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)|
|_Attribute.GetTypeInfo||Retrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)|
|_Attribute.GetTypeInfoCount||Retrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)|
|_Attribute.Invoke||Provides access to properties and methods exposed by an object. (Inherited from Attribute.)|
You can apply this attribute to classes or structures.
The common language runtime controls the physical layout of the data fields of a class or structure in managed memory. However, if you want to pass the type to unmanaged code, you can use the attribute to control the unmanaged layout of the type. Use the attribute with LayoutKind.Sequential to force the members to be laid out sequentially in the order they appear. For blittable types, LayoutKind.Sequential controls both the layout in managed memory and the layout in unmanaged memory. For non-blittable types, it controls the layout when the class or structure is marshaled to unmanaged code, but does not control the layout in managed memory. Use the attribute with LayoutKind.Explicit to control the precise position of each data member. This affects both managed and unmanaged layout, for both blittable and non-blittable types. Using LayoutKind.Explicit requires that you use the FieldOffsetAttribute attribute to indicate the position of each field within the type.
C#, Visual Basic, and C++ compilers apply the Sequential layout value to structures by default. For classes, you must apply the LayoutKind.Sequential value explicitly. The Tlbimp.exe (Type Library Importer) also applies the attribute; it always applies the LayoutKind.Sequential value when it imports a type library.
The following example demonstrates a managed declaration of the GetSystemTime function and defines MySystemTime class with LayoutKind.Explicit layout. GetSystemTime gets the system time and prints to the console.
.NET FrameworkSupported in: 4.5.3, 4, 3.5, 3.0, 2.0, 1.1, 1.0
.NET Framework Client ProfileSupported in: 4, 3.5 SP1
Portable Class LibrarySupported in: Portable Class Library
.NET for Windows Store appsSupported in: Windows 8
Supported in: Windows Phone 8.1
Supported in: Windows Phone Silverlight 8.1
Supported in: Windows Phone Silverlight 8
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.