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MemberInfo.GetCustomAttributes Method (Boolean)

Updated: January 2010

When overridden in a derived class, returns an array of all custom attributes applied to this member.

Namespace:  System.Reflection
Assembly:  mscorlib (in mscorlib.dll)
public abstract Object[] GetCustomAttributes(
	bool inherit
)

Parameters

inherit
Type: System.Boolean
true to search this member's inheritance chain to find the attributes; otherwise, false. This parameter is ignored for properties and events; see Remarks.

Return Value

Type: System.Object[]
An array that contains all the custom attributes applied to this member, or an array with zero elements if no attributes are defined.

Implements

ICustomAttributeProvider.GetCustomAttributes(Boolean)
_MemberInfo.GetCustomAttributes(Boolean)
Exception Condition
InvalidOperationException

This member belongs to a type that is loaded into the reflection-only context. See How to: Load Assemblies into the Reflection-Only Context.

TypeLoadException

A custom attribute type could not be loaded.

This method ignores the inherit parameter for properties and events. To search the inheritance chain for attributes on properties and events, use the appropriate overloads of the Attribute.GetCustomAttributes method.

Note Note:

In the .NET Framework version 2.0, this method returns security attributes on methods, constructors, and types if they are stored in the new metadata format. Assemblies compiled with version 2.0 use this format. Dynamic assemblies and assemblies compiled with earlier versions of the .NET Framework use the old XML format. See Emitting Declarative Security Attributes.

The following example defines a custom attribute and associates the attribute with MyClass.MyMethod, retrieves the attribute at run time, and displays the result.

using System;
using System.Reflection;

// Define a custom attribute with one named parameter.
[AttributeUsage(AttributeTargets.All)]
public class MyAttribute : Attribute
{
    private string myName;
    public MyAttribute(string name)
    {
        myName = name;
    }
    public string Name
    {
        get
        {
            return myName;
        }
    }
}

// Define a class that has the custom attribute associated with one of its members.
public class MyClass1
{
    [MyAttribute("This is an example attribute.")]
    public void MyMethod(int i)
    {
        return;
    }
}

public class MemberInfo_GetCustomAttributes
{
    public static void Main()
    {
        try
        {
            // Get the type of MyClass1.
            Type myType = typeof(MyClass1);
            // Get the members associated with MyClass1.
            MemberInfo[] myMembers = myType.GetMembers();

            // Display the attributes for each of the members of MyClass1.
            for(int i = 0; i < myMembers.Length; i++)
            {
                Object[] myAttributes = myMembers[i].GetCustomAttributes(true);
                if(myAttributes.Length > 0)
                {
                    Console.WriteLine("\nThe attributes for the member {0} are: \n", myMembers[i]);
                    for(int j = 0; j < myAttributes.Length; j++)
                        Console.WriteLine("The type of the attribute is {0}.", myAttributes[j]);
                }
            }
        }
        catch(Exception e)
        {
            Console.WriteLine("An exception occurred: {0}", e.Message);
        }
    }
}


Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

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

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

Date

History

Reason

January 2010

Clarified that the inherit parameter is ignored for properties and events.

Customer feedback.

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Generic extensions for retrieving custom attributes

As most of the Reflection classes, such as Type, MemberInfo, and ParameterInfo, all implement ICustomAttributeProvider, you can add some extension methods (new to C# 3.0 and Visual Basic 9.0) to extend this interface to make retrieving attributes a little easier.

For example:

[C#]
using System;
using System.Reflection;

public static class CustomAttributeProviderExtensions
{
public static T[] GetCustomAttributes<T>(this ICustomAttributeProvider provider) where T : Attribute
{
return GetCustomAttributes<T>(provider, true);
}

    public static T[] GetCustomAttributes<T>(this ICustomAttributeProvider provider, bool inherit) where T : Attribute
{
if (provider == null)
throw new ArgumentNullException("provider");

        T[] attributes = provider.GetCustomAttributes(typeof(T), inherit) as T[];
if (attributes == null)
{ // WORKAROUND: Due to a bug in the code for retrieving attributes
// from a dynamic generated parameter, GetCustomAttributes can return
// an instance of an object[] instead of T[], and hence the cast above
// will return null.
            return new T[0];
}

        return attributes;
}
}

This allows you to do the following:

[C#]

[Serializable]
class Program
{
static void Main(string[] args)
{
SerializableAttribute[] attributes = typeof(Program).GetCustomAttributes<SerializableAttribute>();
        foreach (var attribute in attributes)
{
Console.WriteLine(attribute);
}
}
}

Which outputs the following:

SerializableAttribute