object o= t.GetProperty(propertyname).GetValue()obj,null;
泛型<你定义的类型> p = o as  泛型<你定义的类型>;

泛型<你定义的类型> p = o as  泛型<你定义的类型>; 
p.add();

我的所有对像都是用反射创建的不能用上面的方法

if ((item.PropertyType.IsGenericType) && (column.SubItems != null))
                            {
                                Type ftype = value.GetType();
                                var slistobj = CreateObject(column.SubItems.Assembly, column.SubItems.Type, true);
                                Type ssType = slistobj.GetType();
                                MethodInfo method = ssType.GetMethod("Add");
                                BindingFlags flag = BindingFlags.Public;

                                //List<object> liobj = new List<object>();                                
                                _tobj = CreateObject(column.SubItems.Assembly, column.SubItems.Type);

                                int count = Convert.ToInt32(ftype.GetProperty("Count").GetValue(value, null));
                                object[] arrobj=new object[count];

                                for (int i = 0; i < count; i++)
                                {                                   
                                    object listItem = ftype.GetProperty("Item").GetValue(value, new object[] { i });
                                    GetSubItem(column.SubItems, listItem, ref _tobj, listItem.GetType(), _tobj.GetType());
                                    
                                    object[] parameters = new object[1];
                                    parameters[0] = _tobj;

                                    Object robj = method.Invoke(slistobj, flag, Type.DefaultBinder, parameters, null);
                                    //GetSubItem(column.SubItems, listItem, ref _tobj, listItem.GetType(), _tobj.GetType());
                                    //GetSubItem(column.SubItems, listItem, ref slistobj, listItem.GetType(), _tobj.GetType());
                                    //arrobj[i] = listItem;
                                    //liobj.Add(_tobj);
                                    //liobj.Add(ss);
                                    //item.SetValue(Tobj, listItem,null;
                                }

                                item.SetValue(Tobj, slistobj, null);                                
                            }