How do I get all class using custom attribute

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Hi there.
i have a class AIName extends Attribute like this:

C#

public class AIName : Attribute
    {
        /// <summary>
        /// Return name of AI
        /// </summary>
        /// <returns></returns>
        private string name;
        public AIName(string name)
        {
            this.name = name;
        }
        public string GetAIName()
        {
            return name;
        }
    }

and few class using custom attribute like this:

C#

[AIName("aggressive")]
    public class AggressiveNpcAI2 : GeneralNpcAI2
    {
    }

[AIName("npc")]
    public class NpcAI2 : AITemplate
    {
    }

So i would like to get all custom attribute where classes using AIName attribute.

What I have tried:

I tried this code below but its just can get 1 class that i give class name only.

C#

public void Init()
        {
            Type type = typeof(AggressiveNpcAI2);
            object[] attributes = type.GetCustomAttributes(true);
            foreach (object attribute in attributes)
            {
                AIName da = attribute as AIName;
                if (da != null)
                    Console.WriteLine("AI Name: {0}", da.GetAIName());
                else
                    Console.WriteLine();
            }
        }

Posted 8-Dec-16 4:19am

EADever

Updated 8-Dec-16 5:15am

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Comments

Simon_Whale 8-Dec-16 10:36am

Is there only one attribute per class?

EADever 8-Dec-16 10:38am

Yes, only one attribute per class.

3 solutions

Solution 2

Thanks @OriginalGriff for your sugguestion.
Im done my code and its work well:

C#

Assembly myAssembly = Assembly.GetExecutingAssembly();
            Type[] types = myAssembly.GetTypes();
            foreach (Type typeA in types)
            {
                foreach (object attribute in typeA.GetCustomAttributes(true))
                {
                    AIName da = attribute as AIName;
                    if (da != null)
                    {
                        Add<AggressiveNpcAI2>(da.GetAIName());
                        Console.WriteLine("AI Name: {0}", da.GetAIName());
                    }
                }
            }

Posted 8-Dec-16 5:04am

EADever

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OriginalGriff · Accepted Answer · 2016-12-08T04:50:00

Solution 1

If you can do it for one, named type then you can do it for all the types in your assembly. This will list them all:

C#

Assembly myAssembly = Assembly.GetExecutingAssembly();
Type[] types = myAssembly.GetTypes();
foreach (Type type in types)
    {
    Console.WriteLine(type.FullName);
    }

So you can combine that with your code to find them all.

Posted 8-Dec-16 4:50am

OriginalGriff

Comments

EADever 8-Dec-16 10:58am

can you give more details?

OriginalGriff 8-Dec-16 11:04am

What more details do you need?
You have code you wrote to check if a specific type is decorated with your attribute, and I gave you code to find all the types in your assembly.
So what is the problem with putting the two bits of code together?

Simon_Whale · Accepted Answer · 2016-12-08T05:15:00

To add to what Griff has given

C#

Assembly asm = Assembly.GetExecutingAssembly();
foreach(Type type in asm.GetTypes())
{
  //Now if your classes are in a different folder in the same assembly then
  //you will need to specify the full name space address for example
  //"projectName.Classes" (I have assumed that you have a folder in the app called Classes)
  if(type.Namespace == "full namespace address here")
  {
    //do what is needed here
  }
}

if you are having to load the files from an external assembly then change the first line to

C#

Assembly asm - Assembly.LoadFromFile("path to dll");

reflection - Loading DLLs at runtime in C# - Stack Overflow[^]