Question

I have found following code to get all action from controller name.

Type t = typeof(YourControllerType);
MethodInfo[] mi = t.GetMethods();
foreach (MethodInfo m in mi)
{
    if (m.IsPublic)
        if (typeof(ActionResult).IsAssignableFrom(m.ReturnParameter.ParameterType))
            methods = m.Name + Environment.NewLine + methods;
}

I want to make following code dynamic as function by passing controller name as follows:

 public string get_all_action(type ob)
        {
            string methods = "";
            Type t = typeof(ob);
            MethodInfo[] mi = t.GetMethods();

            foreach (MethodInfo m in mi)
            {
                if (m.IsPublic)
                    if (typeof(ActionResult).IsAssignableFrom(m.ReturnParameter.ParameterType))
                        methods = m.Name + Environment.NewLine + methods;
            }

            return methods;
        }

But I am confuse what type of parameter should passed to the function at definition and while calling the function.
I have following code to get all controller and pass controller name to get_all_action().

var asm = Assembly.GetExecutingAssembly();
            var controllerTypes = from d in asm.GetExportedTypes() where typeof(IController).IsAssignableFrom(d) select d;
            foreach(var val in controllerTypes)
            {                
               string actionname = get_all_action(val.Name);


            }

Here, val.Name is in string type therefore it throws exception:

Object reference not set to an instance of an object.

Answer 1

Your get_all_action method is expecting to receive a Type as the input parameter, whereas you’re attempting to call it with a String (i.e. the Type name) as the input parameter.

The line here:

string actionname = get_all_action(val.Name);

should instead be:

string actionname = get_all_action(val);

And the first few lines of your get_all_action method should be changed to be:

public string get_all_action(Type controllerType)
{
    string methods = "";
    MethodInfo[] mi = controllerType.GetMethods();