CODEWITHSUNDEEP
uwpc++17winrt-xamlc++-winrt
Dean Chalk
Dean Chalk

Reputation: 20471

Cannot access Windows::UI::Xaml::Controls::ItemCollection.Size

Im fairly new to C++ so sorry if this is obvious, but I cannot access the property 'Size' on the type Windows::UI::Xaml::Controls::ItemCollection.

Here is my code:

Windows::UI::Xaml::Controls::ItemCollection& items = Items(); // Items in a property of Windows::UI::Xaml::Controls::GridView which my class derives from
auto count = items.Size(); // -> build error

The error is 'winrt::impl::consume_Windows_Foundation_Collections_IVector::Size': a function that returns 'auto' cannot be used before it is defined

I know that ItemCollection has a Size property, so why is the compiler complaining that it isnt defined.

Any help would be really appreciated

Thanks

Upvotes: 0

Views: 95

Answers (1)

IInspectable
IInspectable

Reputation: 51497

You forgot to include a header file that provides the definition of the template, probably <winrt/Windows.Foundation.Collections.h. This particular compiler error used to be a linker error, that was a lot harder to interpret.

Raymond Chen blogged about the changes that went into C++/WinRT to 'promote' this linker error into a compiler error: Why does my C++/WinRT project get errors of the form “consume_Something: function that returns ‘auto’ cannot be used before it is defined”?

Upvotes: 2

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