Question

I have following function to return the selectlist of the action name from controller name of string type:

public ActionResult get_all_action(string controllername)
        {
            Type t = Type.GetType(controllername);
            MethodInfo[] mi = t.GetMethods();

            List<SelectListItem> action = new List<SelectListItem>();

            foreach (MethodInfo m in mi)
            {
                if (m.IsPublic)
                    if (typeof(ActionResult).IsAssignableFrom(m.ReturnParameter.ParameterType))
                    {
                        action.Add(new SelectListItem() { Value = m.Name, Text = m.Name });
                    }
            }

            var List = new SelectList(action, "Value", "Text");

            return Json(List, JsonRequestBehavior.AllowGet);
        }

The parameter controllername of get_all_action() is passed as for example “AccountController”. But the exception is thrown at

MethodInfo[] mi = t.GetMethods();

as:

Object reference not set to an instance of an object.

Answer 1

"AccountController" is not a full type name; it needs to be something like "YourApp.Whatever.AccountController" for GetType() to find it. It is also worth making it explicit which assembly it is in, for example:

var thisType = GetType();
Type t = thisType.Assembly.GetType(
    thisType.Namespace + "." + controllerName);

(which assumes we mean the same assembly / namespace)