FieldOffsetAttribute Class

Definition

Namespace:

System.Runtime.InteropServices

Assembly:

System.Runtime.dll

Source:

FieldOffsetAttribute.cs

Indicates the physical position of fields within the unmanaged representation of a class or structure.

public ref class FieldOffsetAttribute sealed : Attribute

[System.AttributeUsage(System.AttributeTargets.Field, Inherited=false)]
public sealed class FieldOffsetAttribute : Attribute

[<System.AttributeUsage(System.AttributeTargets.Field, Inherited=false)>]
type FieldOffsetAttribute = class
    inherit Attribute

Public NotInheritable Class FieldOffsetAttribute
Inherits Attribute

Inheritance

Object

Attribute

FieldOffsetAttribute

Attributes

AttributeUsageAttribute

Examples

The following example demonstrates how to apply the FieldOffsetAttribute to members of a struct or class with an explicit layout.

[StructLayout(LayoutKind::Explicit)]
public ref class SYSTEM_INFO
{
public:

   [FieldOffset(0)]
   UInt64 OemId;

   [FieldOffset(8)]
   UInt64 PageSize;

   [FieldOffset(24)]
   UInt64 ActiveProcessorMask;

   [FieldOffset(32)]
   UInt64 NumberOfProcessors;

   [FieldOffset(40)]
   UInt64 ProcessorType;
};

[StructLayout(LayoutKind.Explicit)]
public struct SYSTEM_INFO
{
[FieldOffset(0)] public ulong OemId;
[FieldOffset(8)] public ulong PageSize;
[FieldOffset(16)] public ulong ActiveProcessorMask;
[FieldOffset(24)] public ulong NumberOfProcessors;
[FieldOffset(32)] public ulong ProcessorType;
}

<StructLayout(LayoutKind.Explicit)> _
Public Class SYSTEM_INFO
    <FieldOffset(0)> Private OemId As System.UInt64
    <FieldOffset(8)> Private PageSize As System.UInt64
    <FieldOffset(16)> Private ActiveProcessorMask As System.UInt64
    <FieldOffset(24)> Private NumberOfProcessors As System.UInt64
    <FieldOffset(32)> Private ProcessorType As System.UInt64
End Class

For a larger example, see the System.Runtime.InteropServices.StructLayoutAttribute class.

Remarks

You can apply this attribute to fields.

This attribute is used when System.Runtime.InteropServices.StructLayoutAttribute, with LayoutKind.Explicit passed to its constructor, is applied to a class or structure to specify the offset of each non- static or constant member within the unmanaged representation of that class or structure.

Constructors

FieldOffsetAttribute(Int32)

Initializes a new instance of the FieldOffsetAttribute class with the offset in the structure to the beginning of the field.

Properties

TypeId	When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute)
Value	Gets the offset from the beginning of the structure to the beginning of the field.

Methods

Equals(Object)	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(Object)	When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)

See also

• LayoutKind