Find methods that have custom attribute using reflection

Question

I have a custom attribute:

public class MenuItemAttribute : Attribute
{
}

and a class with a few methods:

public class HelloWorld
{
    [MenuItemAttribute]
    public void Shout()
    {
    }

    [MenuItemAttribute]
    public void Cry()
    {
    }

    public void RunLikeHell()
    {
    }
}

How can I get only the methods that are decorated with the custom attribute?

So far, I have this:

string assemblyName = fileInfo.FullName;
byte[] assemblyBytes = File.ReadAllBytes(assemblyName);
Assembly assembly = Assembly.Load(assemblyBytes);

foreach (Type type in assembly.GetTypes())
{
     System.Attribute[] attributes = System.Attribute.GetCustomAttributes(type);

     foreach (Attribute attribute in attributes)
     {
         if (attribute is MenuItemAttribute)
         {
             //Get me the method info
             //MethodInfo[] methods = attribute.GetType().GetMethods();
         }
     }
}

What I need now is to get the method name, the return type, as well as the parameters it accepts.

SLaks · Accepted Answer · 2010-08-12 12:49:48Z

118

Your code is completely wrong.
You are looping through every type that has the attribute, which will not find any types.

You need to loop through every method on every type and check whether it has your attribute.

For example:

var methods = assembly.GetTypes()
                      .SelectMany(t => t.GetMethods())
                      .Where(m => m.GetCustomAttributes(typeof(MenuItemAttribute), false).Length > 0)
                      .ToArray();

answered Aug 12, 2010 at 12:49

SLaks

891k182 gold badges1.9k silver badges2k bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

stoic Over a year ago

am i doing it ass-about-front here? cause right now i look for all the attributes and i then try and get the associated method

SLaks Over a year ago

I tried it with your classes; it works for me. Are you searching the right assembly?

stoic Over a year ago

doh... changed some of the code to make it simple for stackoverflow readers... never changed it back... thanx... yours is correct

SLaks Over a year ago

@Tom: GetCustomAttributes() returns an array anyway, so .Any() won't help.

Sachin Joseph Over a year ago

use Assembly.GetExecutingAssembly() for the currently executing assembly

|

JordanBean · Accepted Answer · 2013-01-16 15:45:04Z

25

Dictionary<string, MethodInfo> methods = assembly
    .GetTypes()
    .SelectMany(x => x.GetMethods())
    .Where(y => y.GetCustomAttributes().OfType<MethodAttribute>().Any())
    .ToDictionary(z => z.Name);

answered Jan 16, 2013 at 15:45

JordanBean

2,8512 gold badges28 silver badges32 bronze badges

Comments

Matt · Accepted Answer · 2021-10-08 11:21:27Z

6

var classType = new ClassNAME();
var methods = classType.GetType().GetMethods().Where(m=>m.GetCustomAttributes(typeof(MyAttribute), false).Length > 0)
.ToArray();

Now you have all methods with this attribute MyAttribute in class classNAME. You can invoke it anywhere.

public class ClassNAME
{
    [MyAttribute]
    public void Method1(){}

    [MyAttribute]
    public void Method2(){}

    public void Method3(){}
}

class MyAttribute: Attribute { }

edited Oct 8, 2021 at 11:21

Matt

27.4k19 gold badges131 silver badges202 bronze badges

answered Jul 3, 2019 at 11:36

Unknown Artist

1531 silver badge9 bronze badges

Collectives™ on Stack Overflow

Find methods that have custom attribute using reflection

3 Answers 3

6 Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

6 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related