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.NET Framework Class Library
MethodImplAttribute Class

Updated: September 2010

Specifies the details of how a method is implemented. This class cannot be inherited.

Inheritance Hierarchy
System..::.Object
  System..::.Attribute
    System.Runtime.CompilerServices..::.MethodImplAttribute

Namespace: System.Runtime.CompilerServices
Assembly: mscorlib (in mscorlib.dll)
Syntax
<SerializableAttribute> _
<ComVisibleAttribute(True)> _
<AttributeUsageAttribute(AttributeTargets.Constructor Or AttributeTargets.Method, Inherited := False)> _
Public NotInheritable Class MethodImplAttribute _
	Inherits Attribute
[SerializableAttribute]
[ComVisibleAttribute(true)]
[AttributeUsageAttribute(AttributeTargets.Constructor|AttributeTargets.Method, Inherited = false)]
public sealed class MethodImplAttribute : Attribute
[SerializableAttribute]
[ComVisibleAttribute(true)]
[AttributeUsageAttribute(AttributeTargets::Constructor|AttributeTargets::Method, Inherited = false)]
public ref class MethodImplAttribute sealed : public Attribute
[<Sealed>]
[<SerializableAttribute>]
[<ComVisibleAttribute(true)>]
[<AttributeUsageAttribute(AttributeTargets.Constructor|AttributeTargets.Method, Inherited = false)>]
type MethodImplAttribute =  
    class
        inherit Attribute
    end

The MethodImplAttribute type exposes the following members.

Constructors
 NameDescription
Public methodSupported by the XNA FrameworkMethodImplAttribute()()()Initializes a new instance of the MethodImplAttribute class.
Public methodSupported by the XNA FrameworkMethodImplAttribute(Int16)Initializes a new instance of the MethodImplAttribute class with the specified MethodImplOptions value.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryMethodImplAttribute(MethodImplOptions)Initializes a new instance of the MethodImplAttribute class with the specified MethodImplOptions value.
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Properties
 NameDescription
Public propertyTypeIdWhen implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)
Public propertySupported by the XNA FrameworkSupported by Portable Class LibraryValueGets the MethodImplOptions value describing the attributed method.
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Methods
 NameDescription
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryEqualsInfrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Protected methodSupported by the XNA FrameworkSupported by Portable Class LibraryFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryGetHashCodeReturns the hash code for this instance. (Inherited from Attribute.)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodIsDefaultAttributeWhen overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public methodSupported by the XNA FrameworkMatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Protected methodSupported by the XNA FrameworkSupported by Portable Class LibraryMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryToStringReturns a string that represents the current object. (Inherited from Object.)
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Fields
 NameDescription
Public fieldSupported by the XNA FrameworkMethodCodeTypeA MethodCodeType value indicating what kind of implementation is provided for this method.
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Explicit Interface Implementations
 NameDescription
Explicit interface implemetationPrivate method_Attribute..::.GetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute..::.GetTypeInfoRetrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute..::.GetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute..::.InvokeProvides access to properties and methods exposed by an object. (Inherited from Attribute.)
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Remarks

You can apply this attribute to methods or constructors.

This attribute lets you customize the configuration of the method or constructor to which it applies by supplying a MethodImplOptions value to its class constructor. The members of the MethodImplOptions enumeration correspond to bit fields in the CorMethodImpl metadata table. This means that information on the attribute cannot be retrieved at run time by calling the MemberInfo..::.GetCustomAttributes method; instead, it is retrieved by calling either the MethodInfo.GetMethodImplementationFlags or the ConstructorInfo.GetMethodImplementationFlags method.

Examples

The following example applies the MethodImplAttribute to the GetCalendarName method to ensure that it is not inlined at run time by the just-in-time (JIT) compiler.


Imports System.Globalization
Imports System.Runtime.CompilerServices

Public Class Utility
   <MethodImplAttribute(MethodImplOptions.NoInlining)>
   Public Shared Function GetCalendarName(cal As Calendar) As String
      Return cal.ToString().Replace("System.Globalization.", "").Replace("Calendar", "")
   End Function
End Class


using System;
using System.Globalization;
using System.Runtime.CompilerServices;

public class Utility
{
   [MethodImplAttribute(MethodImplOptions.NoInlining)] 
   public static string GetCalendarName(Calendar cal)
   {
      return cal.ToString().Replace("System.Globalization.", "").
                 Replace("Calendar", "");
   }
}

The following example then calls the MethodInfo.GetMethodImplementationFlags method to determine which flags are set for the GetCalendarName method. It also demonstrates that this information is not retrieved by the MemberInfo..::.GetCustomAttributes method.


Imports System.Reflection

Module Example
   Public Sub Main()
      ' Use reflection to get a reference to the GetCalendarName method.
      Dim assem As Assembly = Assembly.LoadFrom(".\Example.dll")
      Dim type As Type = assem.GetType("Utility")
      Dim methodInfo As MethodInfo = type.GetMethod("GetCalendarName")

      ' Determine whether the method has any custom attributes.
      Console.Write("Utility.GetCalendarName custom attributes:")
      Dim attribs() As Object = methodInfo.GetCustomAttributes(False)
      If attribs.Length > 0 Then
         Console.WriteLine()
         For Each attrib As Object In attribs
            Console.WriteLine("   " + attrib.ToString())   
         Next
      Else
         Console.WriteLine("   <None>")
      End If

      ' Get the method's metadata flags.
      Dim flags As MethodImplAttributes = methodInfo.GetMethodImplementationFlags()
      Console.WriteLine("Utility.GetCalendarName flags: {0}", flags.ToString())      
   End Sub
End Module
' The example displays the following output:
'     Utility.GetCalendarName custom attributes:   <None>
'     Utility.GetCalendarName flags: NoInlining


using System;
using System.Reflection;

public class Example
{
   public static void Main()
   {
      // Use reflection to get a reference to the GetCalendarName method.
      Assembly assem = Assembly.LoadFrom(@".\Example.dll");
      Type type = assem.GetType("Utility");
      MethodInfo methodInfo = type.GetMethod("GetCalendarName");

      // Determine whether the method has any custom attributes.
      Console.Write("Utility.GetCalendarName custom attributes:");
      object[] attribs = methodInfo.GetCustomAttributes(false);
      if (attribs.Length > 0) {
         Console.WriteLine();
         foreach (var attrib in attribs)
            Console.WriteLine("   " + attrib.ToString());   

      }
      else {
         Console.WriteLine("   <None>");
      }

      // Get the method's metadata flags.
      MethodImplAttributes flags = methodInfo.GetMethodImplementationFlags();
      Console.WriteLine("Utility.GetCalendarName flags: {0}", 
                        flags.ToString());      
   }
}
// The example displays the following output:
//     Utility.GetCalendarName custom attributes:   <None>
//     Utility.GetCalendarName flags: NoInlining

Version Information

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library
Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Thread Safety
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
Change History

Date

History

Reason

September 2010

Revised extensively.

Customer feedback.