如何在不使用新的情况下访问类别Froma的另一类 [英] How Do I Access A Class Froma Another Class Without Using New

问题描述

我试过MainWindow主;但它没有任何用处，我也不想使用新的..

i tried MainWindow main;. but it wasn't of any use and i dont want to use new for the same..

推荐答案

当你使用 new 你创建了一个类的新实例，它的所有字段和属性都独立于任何现有实例：它就像汽车一样。你把你的钱包放在汽车的手套箱里，然后买一辆新车 - 你希望在新车的手套箱里找到你的钱包吗？



所以如果您尝试访问现有的主窗口，则表示您不能使用 new - 您需要获取用户正在查看的窗口的实际实例。 />


如果您是在MainWindow类中执行此操作，那么这很简单 - 您无需执行任何操作，因为您的代码将自动引用当前实例你使用属性或字段名称（除非你在静态方法中，没有实例）。



如果你在课外，那么它很多，更难 - 并且将取决于你的代码如何工作 - 因为你通常不希望代码引用外部窗口，因为这打破了OOP原则。您实际需要实现的是什么？

When you use new you create a new instance of the class, which has all it's fields and properties independent to any existing instances: it's like cars. It you put your wallet in the glove box of your car, then buy a new car - would you expect to find your wallet in the new car's glove box?

So you are right not to use new if you are trying to access the existing main window - you need to get the actual instance of the window that the user is looking at.

If you are doing this from within the MainWindow class, then that;s pretty easy - you don't have to do anything because your code will automatically reference the current instance when you use a property or field name (unless you are inside a static method, where there is no instance).

If you are outside the class, then it's a lot, lot harder - and will depend on how your code works - because you wouldn't normally want code to refer to external windows as that breaks the OOPs principles. What are you actually trying to achieve that you need this?

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