如何使用cppwinrt声明OnPointerEntered的处理程序？ [英] How to declare handler for OnPointerEntered using cppwinrt?

问题描述

在cppwinrt（尚未提供xaml）中，我有一个Button的PointerEntered事件的处理程序，它可以正常工作。但是在尝试删除此Button（显示为图像）的默认悬停行为时，似乎我可能需要处理OnPointerEntered事件-我已经看到了涉及使用xaml触发器的解决方案，这似乎与代码等效。但是OnPointerEntered具有不同的参数列表，我找不到一种可以构建它的方法。以下是成功声明PointerEntered事件句柄的方式：

In cppwinrt (xaml not yet available) I have a handler for the PointerEntered event of a Button, and it works fine. But in attempting to remove the default hover behavior of this Button, which displays as an image, it seems I may need to handle the OnPointerEntered event instead - I have seen solutions that involve using a xaml trigger and this would seem to be a code equivalent. But OnPointerEntered has a different argument list, and I can't find a way to invoke it that will build. Here is how the PointerEntered event handle is successfully declared:

button.PointerEntered([&](winrt::Windows::Foundation::IInspectable const & sender, Windows::UI::Xaml::RoutedEventArgs const & args) { EnteredButton(); });

这会生成并正确调用EnteredButton。但是

That builds and correctly calls EnteredButton. But

button.OnPointerEntered([&](winrt::Windows::UI::Xaml::Input::PointerRoutedEventArgs const & e)
{
    EnteredButton();
});

将无法生成-我尝试了多种变体后，声明错误，但不确定如何。 （使用完全限定的名称可能不是必需的，但在任何情况下似乎都不会受到损害）。可以在cppwinrt中使用OnPointerEntered，如果可以的话如何声明？我尝试使用IPointerRoutedEventArgs代替PointerRoutedEventArgs无效。或者-如果有人知道用cppwinrt创建的Button中禁用悬停效果的另一种方法，那将起作用。

will not build - I am declaring it incorrectly but am not sure how, after trying a number of variants. (Using the fully-qualified names is maybe not necessary, but seems not to hurt in either case). Can OnPointerEntered be used in cppwinrt, and how would it be declared if so? I have tried using IPointerRoutedEventArgs instead of PointerRoutedEventArgs with no effect. Or - if anyone knows a different way to disable the hover effect in a Button created with cppwinrt, that would work.

推荐答案

您不能满足你的要求回应IInspectable的评论：

You can't do what you're asking. Echoing IInspectable's comment:

• PointerEntered是Windows :: UI :: Xaml :: UIElement上的事件。您的代码正确地声明了它的处理程序。


• OnPointerEntered是不是事件，因此无法对其进行处理。这是一种可重写的方法，您可以为其提供自己的实现。

• PointerEntered is an event on Windows::UI::Xaml::UIElement. Your code is correctly declaring a handler for it.
• OnPointerEntered is not an event, so there is no way to handle it. It is an overridable method for which you can provide your own implementation.

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