创建类的句柄财产

发布于 2024-08-31 03:21:43 字数 188 浏览 2 评论 0原文

是否可以为类的属性创建一个句柄（或跟踪句柄）？例如，

System::Windows::Forms::CheckBox^ Box = gcnew System::Windows::Forms::CheckBox()

我想创建 Box 的 Checked 属性的句柄，并使用它来访问和修改该属性。

原文

Would it be possible to create a handle ( or a tracking handle ) to a class' property ? For instance,

System::Windows::Forms::CheckBox^ Box = gcnew System::Windows::Forms::CheckBox()

I'd like to create a handle to Box's Checked property and use it to access and modify the same.

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浮生面具三千个 2024-09-07 03:21:43

属性只不过是 set/get 方法的语法糖，据我所知，没有办法捕获对属性的任何类型的引用（我想类似于绑定方法）。

我能想到的最好的解决方法（需要 VS2010）是传递几个 lambda：

auto set = [=](bool b) { Box->Checked = b; };
auto get = [=]() -> bool { return Box->Checked; };

编辑（因为你没有 VS2010）：

你当然可以恢复到编写专用类的更巴洛克惯例：

public generic<typename T> interface class PropertyProxy
{
    property T Field;
};

public ref class CheckBoxChecked : public PropertyProxy<bool>
{
public:
    CheckBoxChecked(System::Windows::Forms::CheckBox^ box) : _box(box) { }
    property bool Field
    {
        bool get() { return _box->Checked; };
        void set(bool b) { _box->Checked = b; };
    }

private:
    System::Windows::Forms::CheckBox^ _box;
};

如果有人问你 C++ lambda 有什么用处，那么很难跳过这个例子。

Properties are little more than syntactic sugar for set/get methods, and there is, AFAIK, no way to capture any kind of reference to one (something akin to a bound Method, I suppose).

The best workaround I can think of, which requires VS2010, is to pass a couple of lambdas around:

auto set = [=](bool b) { Box->Checked = b; };
auto get = [=]() -> bool { return Box->Checked; };

EDIT (since you don't have VS2010):

You can of course revert to the rather more baroque convention of writing a special-purpose class:

public generic<typename T> interface class PropertyProxy
{
    property T Field;
};

public ref class CheckBoxChecked : public PropertyProxy<bool>
{
public:
    CheckBoxChecked(System::Windows::Forms::CheckBox^ box) : _box(box) { }
    property bool Field
    {
        bool get() { return _box->Checked; };
        void set(bool b) { _box->Checked = b; };
    }

private:
    System::Windows::Forms::CheckBox^ _box;
};

If anyone ever asks you what C++ lambdas are good for, it's hard to go past this example.

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