MethodImplAttribute Class

Definition

Namespace:

System.Runtime.CompilerServices

Assembly:

System.Runtime.dll

Source:

MethodImplAttribute.cs

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

public ref class MethodImplAttribute sealed : Attribute

[System.AttributeUsage(System.AttributeTargets.Constructor | System.AttributeTargets.Method, Inherited=false)]
public sealed class MethodImplAttribute : Attribute

[<System.AttributeUsage(System.AttributeTargets.Constructor | System.AttributeTargets.Method, Inherited=false)>]
type MethodImplAttribute = class
    inherit Attribute

Public NotInheritable Class MethodImplAttribute
Inherits Attribute

Inheritance

Object

Attribute

MethodImplAttribute

Attributes

AttributeUsageAttribute

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.

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", "");
   }
}

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

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.

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

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

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.

Constructors

MethodImplAttribute()	Initializes a new instance of the MethodImplAttribute class.
MethodImplAttribute(Int16)	Initializes a new instance of the MethodImplAttribute class with the specified MethodImplOptions value.
MethodImplAttribute(MethodImplOptions)	Initializes a new instance of the MethodImplAttribute class with the specified MethodImplOptions value.

Fields

MethodCodeType

A MethodCodeType value indicating what kind of implementation is provided for this method.

Properties

TypeId	When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute)
Value	Gets the MethodImplOptions value describing the attributed method.

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

• GetMethodImplementationFlags()