Article
11/18/2011

MethodImplAttribute Class

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Updated: October 2010

This API supports the .NET Framework infrastructure and is not intended to be used directly from your code.

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

'Declaration
<AttributeUsageAttribute(AttributeTargets.Constructor Or AttributeTargets.Method, Inherited := False)> _
<ComVisibleAttribute(True)> _
Public NotInheritable Class MethodImplAttribute _
    Inherits Attribute

[AttributeUsageAttribute(AttributeTargets.Constructor|AttributeTargets.Method, Inherited = false)]
[ComVisibleAttribute(true)]
public sealed class MethodImplAttribute : Attribute

The MethodImplAttribute type exposes the following members.

Constructors

	Name	Description
	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.

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Properties

	Name	Description
	Value	Gets the MethodImplOptions value describing the attributed method.

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Methods

	Name	Description
	Equals	Infrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
	GetHashCode	Returns the hash code for this instance. (Inherited from Attribute.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	Match	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.)

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Fields

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

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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(ByVal 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 Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      ' Use reflection to get a reference to the GetCalendarName method.
      Dim assem As Assembly = Assembly.GetExecutingAssembly()
      Dim type As Type = assem.GetType("SilverlightApplication.Utility")
      Dim methodInfo As MethodInfo = type.GetMethod("GetCalendarName")

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

      ' Get the method's metadata flags.
      Dim flags As MethodImplAttributes = methodInfo.GetMethodImplementationFlags()
      outputBlock.Text += String.Format("Utility.GetCalendarName flags: {0}", flags.ToString()) & vbCrLf
   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 Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      // Use reflection to get a reference to the GetCalendarName method.
      Assembly assem = Assembly.GetExecutingAssembly();
      Type type = assem.GetType("Utility");
      MethodInfo methodInfo = type.GetMethod("GetCalendarName");

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

      }
      else
      {
         outputBlock.Text += "   <None>" + "\n";
      }

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

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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
October 2010	Revised extensively.	Customer feedback.