Assembly.LoadFrom get Custom Attribute

Question

Question: using only Assembly.LoadFrom and having only the name of a custom attribute how can I find and then instantiate any classes with that named custom attribute?

Code in DLL:

[AttributeUsage(AttributeTargets.All)]
public class ClassAttribute : Attribute
{
    private string myName;
    public ClassAttribute() { }
    public ClassAttribute(string className) 
    {
        myName = className;
    }
    public string MyName { get { return myName; } }
}

//Edit ... added this after initial post
[AttributeUsage(AttributeTargets.All)]
public class MethodAttribute : Attribute
{
    private string myMethodName;
    public MethodAttribute(){}
    public MethodAttribute(string methodName)
    {
        myMethodName = methodName;
    }
    public string MyMethodName { get { return myMethodName; } }
}

[ClassAttribute("The First Class")]
public class myClass
{
    //Edit ... added this after initial post
    [MethodAttribute("Find this method after finding this class")]
    public string methodOne()
    {
        return "This response from myclass methodOne";
    }

    public string methodTwo()
    {
        return "This response from myClass methodTwo";
    }
}

Code in consuming class in separate VS2k12 solution:

Assembly asm = Assembly.LoadFrom(@"C:\References\WebDemoAttributes.dll");

string attributeName = "Find this class using this attribute name";

//using attributeName how can I find WebDemoAttributes.myClass, instantiate it, and then call methodOne()?

Thank you in advance and cheers!

---

This is what I finally came up with for anyone interested in searching for classes in a DLL by custom attribute:

protected void lb_debugInClassLibrary_Click(object sender, EventArgs e)
{
    LinkButton lb = sender as LinkButton;

    Assembly asm1 = Assembly.Load("WebDemoAttributes");

    var classAttributesTypes = asm1.GetTypes().Where(t => t.GetCustomAttributes()
        .Any(a => a.GetType().Name == "ClassAttribute")).ToList();

    foreach (Type type in classAttributesTypes)
    {               
        Attribute[] attrs = Attribute.GetCustomAttributes(type);               

        foreach (Attribute atr in attrs)
        {
            var classWithCustomAttribute = atr as WebDemoAttributes.ClassAttribute;
            if (classWithCustomAttribute.MyName == "The First Class" 
                && lb.ID.ToString().ToLower().Contains("thefirstclass"))
            {
                var mc = Activator.CreateInstance(type) as WebDemoAttributes.MyClass;
                //TODO figure out how to get the attributes decorating mc's methods
                if (lb.ID.ToString().ToLower().Contains("methodone"))
                    lbl_responseFromMyClass.Text = mc.MethodOne();
                else if (lb.ID.ToString().ToLower().Contains("methodtwo"))
                    lbl_responseFromMyClass.Text = mc.MethodTwo();
            } 
            if (classWithCustomAttribute.MyName == "The Second Class" 
                && lb.ID.ToString().ToLower().Contains("thesecondclass"))
            {
                var yc = Activator.CreateInstance(type) as WebDemoAttributes.YourClass;
                if (lb.ID.ToString().ToLower().Contains("methodone"))
                    lbl_responseFromYourClass.Text = yc.MethodOne();
                else if (lb.ID.ToString().ToLower().Contains("methodtwo"))
                    lbl_responseFromYourClass.Text = yc.MethodTwo();
            }
        }
    }
}

Answer 1

var asm = Assembly.LoadFrom(@"C:\References\WebDemoAttributes.dll");

var myClassType = asm.GetTypes()
                     .FirstOrDefault(t => t.GetCustomAttributes()
                     .Any(a => a.GetType().Name == "ClassAttribute"));