| title | description | dev_langs | ms.date | ms.topic | keywords | ms.workload | ||
|---|---|---|---|---|---|---|---|---|
winrt::unbox_value_or function template (C++/WinRT) |
A function template that unwraps (or *unboxes*) a scalar value from inside a reference class object, with a fallback value, so that it can be processed in a function that expects **IInspectable**. |
|
04/10/2018 |
reference |
windows 10, uwp, standard, c++, cpp, winrt, projection, api, reference, box, boxing, unbox, unboxing |
|
Note
You can unbox only scalar values (not arrays) by using the winrt::unbox_value_or function.
A function template that unwraps (or unboxes) a scalar value from inside a reference class object, with a fallback value, so that it can be processed in a function that expects IInspectable. An overload of the function also exists for winrt::hstring. For more details, and code examples, see Boxing and unboxing values to IInspectable with C++/WinRT.
template <typename T>
hstring unbox_value_or(winrt::Windows::Foundation::IInspectable const& value, winrt::hstring const& default_value);
template <typename T, typename = std::enable_if_t<!std::is_same_v<T, winrt::hstring>>>
T unbox_value_or(winrt::Windows::Foundation::IInspectable const& value, T const& default_value);
typename T
A scalar type.
default_value
A fallback value to use should coercing the reference class object to the specified value type not be possible.
value
A reference class object containing a boxed value.
The scalar value contained inside the reference class object, or default_value if unboxing to the specified value type is not possible.
Minimum supported SDK: Windows SDK version 10.0.17134.0 (Windows 10, version 1803)
Namespace: winrt
Header: %WindowsSdkDir%Include<WindowsTargetPlatformVersion>\cppwinrt\winrt\Windows.Foundation.h