subclass

问题 In this post there is the description of "subclass" usage in VBA. I'm looking for the next step of it: when I have first subitem added I want to use it and don't know how. When I write baseItem(1).itemName it doesn't work. I assume it's just because that baseItem is not a collection or an array, but I don't know any other way. 回答1: I assume it's just because that baseItem is not a collection or an array... The baseItem itself is not a collection nor an array. It is just an object of type

问题 RELEVANT INFORMATION: I have a subclass procedure that needs to validate the content of the clipboard before it gets pasted. I have managed to get the content of the clipboard successfully, at least I think so. QUESTION: I do not know how to construct the following if statement ( the following is pseudo code ): if( clipboard content is OK ) defaul handler; else discard message; MY EFFORTS TO SOLVE THIS: So far this is what I have in mind: LRESULT CALLBACK Decimalni( HWND hwnd, UINT message,

问题 How do I subclass QStandardItemModel to use my own Item type (e.g. MyItem instead of QStandardItem )? I mean I know I have to create a class and inherit QStandardItemModel but what next? How do I make it use MyItem everywhere? And yes, MyItem inherits after QStandardItem . 回答1: I think it is impossible. You can subclass QAbstractItemModel to implement a model that use your item class. Also you can use default QStandardItemModel and add your additional object to items using QStandardItem:

问题 I have a Model Property which has subclasses using STI, and which I would like all to use the same controller with only different view partials depending on the subclass. Property Restaurant < Property Landmark < Property It works find except I'm not sure how to discern the subclass inside the controller to render the correct view. Ie. /restaurants works and goes to the properties controller but I can't tell that they want the Restaurant subclass? map.resources :restaurant, :controller =>

问题 I have two classes, public class BookItem { public string BookID { get; set; } public string ItemID { get; set; } public Item Item { get; set; } public ItemType Type { get; set; } public string ParentID { get; set; } public string BoxID { get; set; } public string StyleID { get; set; } public string NotesID { get; set; } public string Code_XAML { get; set; } public string Description_XAML { get; set; } public CompositeCollection SubItems { get; set; } } public class Item : ClaunchBaseClass {

问题 I am trying To subclass My UITableViewDatasource, However My App Crashes with EXC_BAD_ACCESS. No explanations no error messages just crashes. A Sort Version of my DataSource Looks Like This. import UIKit class DataSource :NSObject, UITableViewDataSource{ var tableView:UITableView let CellIdentifier = "Cell" init(tableView : UITableView) { println("Data Source") self.tableView = tableView super.init() self.tableView.dataSource = self } //:MARK UITableViewDataSource //--------------------------

问题 Can a subclass variable be cast to any of its superclasses? Can a superclass variable be assigned any subclass variable? Can a superclass be assigned any variable? If so, can an interface variable be assigned a variable from any implementing class? 回答1: Are all dogs also animals? Are all animals also dogs? If you need an animal, and I give you a dog, is that always acceptable? If you need a dog specifically, but I give you any animal, can that ever be problematic? If you need something you

问题 I am ignoring the warnings and trying to subclass a pandas DataFrame. My reasons for doing so are as follows: I want to retain all the existing methods of DataFrame . I want to set a few additional attributes at class instantiation, which will later be used to define additional methods that I can call on the subclass. Here's a snippet: class SubFrame(pd.DataFrame): def __init__(self, *args, **kwargs): freq = kwargs.pop('freq', None) ddof = kwargs.pop('ddof', None) super(SubFrame, self).__init

问题 For numpy.ndarray subclass, ufunc outputs have the same type. This is good in general but I would like for ufunc with scalar output to return scalar type (such as numpy.float64 ). Example: import numpy as np class MyArray(np.ndarray): def __new__(cls, array): obj = np.asarray(array).view(cls) return obj a = MyArray(np.arange(5)) a*2 # MyArray([0, 2, 4, 6, 8]) => same class as original (i.e. MyArray), ok a.sum() # MyArray(10) => same as original, but here I'd expect np.int64 type(2*a) is type

问题 Maybe its something stupid, but I'm having a problem with a subclass of a DataGridView Control in VS2005 C#. I know I can subclass from almost anything by doing public class MyDataGridView : DataGridView {} no problem, and I put in some things / elements I want applicable globally. Now, I take this gridview and put into a custom user control that will contain other controls too. So I have something like created by the visual designer. I grab some buttons, label, and my derived "MyDataGridView