What is the process for creating a C++/WinRT class that can receive Win32 structures as input for its methods?

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The process for creating a C++/WinRT class that can receive Win32 structures as input for its methods is as follows:

1. Include the necessary Win32 header files in your C++/WinRT class.

2. Declare the Win32 structure as a member of your C++/WinRT class.

3. Define the method(s) that will accept the Win32 structure as input.

4. Inside the method(s), cast the Win32 structure to the equivalent C++/WinRT struct or class.

5. Use the converted C++/WinRT struct or class to perform the necessary operations.

6. When returning values from the method(s), convert the C++/WinRT struct or class back to the Win32 structure.

7. Note that some Win32 structures may require special handling or additional conversion steps, depending on their complexity and data types.

For example, if you were creating a C++/WinRT class to interact with Windows Registry keys, you might define a Win32 REGKEYINFO structure as a member of your class, and create a method that accepts this structure as input:

#include <winreg.h>

namespace winrt::RegistryHelper::implementation
{
    struct RegistryHelper : RegistryHelperT<RegistryHelper>
    {
        REGKEYINFO keyinfo;

        fire_and_forget SetKeyInfo(REGKEYINFO input);

        ...
    };
}

Inside the SetKeyInfo method, you would convert the input REGKEYINFO structure to the equivalent C++/WinRT REGKEYINFO class, and use this class to set the corresponding values:

fire_and_forget SetKeyInfo(REGKEYINFO input)
{
    auto winrtKeyInfo = winrt::RegistryKeyInfo{ input.hKey, input.dwType, input.cbData };
    keyinfo.hKey = winrtKeyInfo.HKey();
    keyinfo.dwType = winrtKeyInfo.Type();
    keyinfo.cbData = winrtKeyInfo.DataSize();

    co_return;
}

When returning values from the method, you would convert the keyinfo member back to a REGKEYINFO structure:

REGKEYINFO GetKeyInfo()
{
    auto winrtKeyInfo = winrt::RegistryKeyInfo{ keyinfo.hKey, keyinfo.dwType, keyinfo.cbData };
    REGKEYINFO output = { winrtKeyInfo.HKey(), winrtKeyInfo.Type(), winrtKeyInfo.DataSize() };
    return output;
}