c++ - 尝试创建回调时出错

Question

#include "stdafx.h"

#include <iostream>
#include <Windows.Foundation.h>
#include <wrl\wrappers\corewrappers.h>
#include <wrl\client.h>
#include <wrl\event.h>
#include <stdio.h>
#include <../winrt/windows.devices.bluetooth.h>
#include <../winrt/windows.devices.bluetooth.advertisement.h>
#include <memory>
#include <functional>

using namespace std;
using namespace Microsoft::WRL;
using namespace Microsoft::WRL::Wrappers;
using namespace ABI::Windows::Foundation;
using namespace ABI::Windows::Devices::Bluetooth::Advertisement;
using namespace ABI::Windows::UI::Input;


// Prints an error string for the provided source code line and HRESULT
// value and returns the HRESULT value as an int.
int PrintError(unsigned int line, HRESULT hr)
{
    wprintf_s(L"ERROR: Line:%d HRESULT: 0x%X\n", line, hr);
    return hr;
}
struct Test {
    Test() {}
    Test(int i) {}

    HRESULT OnConnectionReceived(BluetoothLEAdvertisementWatcher* watcher, BluetoothLEAdvertisementReceivedEventArgs* args) {
        MessageBox(0, L"connected", L"MessageBox caption", MB_OK);
        return S_OK;
    }
};

EventRegistrationToken *watcherToken;


int main()
{
    watcherToken = new EventRegistrationToken();

    // Initialize the Windows Runtime.
    RoInitializeWrapper initialize(RO_INIT_MULTITHREADED);
    if (FAILED(initialize))
    {
        return PrintError(__LINE__, initialize);
    }

    // Get the activation factory for the IBluetoothLEAdvertisementWatcherFactory interface.
    ComPtr<IBluetoothLEAdvertisementWatcherFactory> bleAdvWatcherFactory;
    HRESULT hr = GetActivationFactory(HStringReference(RuntimeClass_Windows_Devices_Bluetooth_Advertisement_BluetoothLEAdvertisementWatcher).Get(), &bleAdvWatcherFactory);
    if (FAILED(hr))
    {
        return PrintError(__LINE__, hr);
    }


    ComPtr<IBluetoothLEAdvertisementWatcher> bleWatcher;
    ComPtr<IBluetoothLEAdvertisementFilter> bleFilter;


    Wrappers::HStringReference class_id_filter2(RuntimeClass_Windows_Devices_Bluetooth_Advertisement_BluetoothLEAdvertisementFilter);
    hr = RoActivateInstance(class_id_filter2.Get(), reinterpret_cast<IInspectable**>(bleFilter.GetAddressOf()));
    hr = bleAdvWatcherFactory->Create(bleFilter.Get(), &bleWatcher);



    if (bleWatcher == NULL)
    {
        cout << "bleWatcher is NULL, err is " << hex << hr;
    }
    else
    {
        bleWatcher->Start();
        Test test;
        //Problem is here
        ComPtr<ITypedEventHandler<BluetoothLEAdvertisementWatcher*, BluetoothLEAdvertisementReceivedEventArgs*>> handler;
        handler = Callback<ITypedEventHandler<BluetoothLEAdvertisementWatcher*, BluetoothLEAdvertisementReceivedEventArgs*> > 
            (std::bind(
                &Test::OnConnectionReceived,
                &test,
                placeholders::_1,
                placeholders::_2
            ));

    hr = bleWatcher->add_Received(handler.Get(), watcherToken);
        while (1) {

            Sleep(1000);
        }
    }


    return 0;
}

我正在尝试处理接收到连接时 bleWatcher 生成的事件，当我尝试创建回调时收到错误消息，错误 C2664“HRESULT Microsoft::WRL::DelegateTraits::CheckReturn(HRESULT)”:无法将参数 1 从“std::_Unforced”转换为“HRESULT”

https://social.msdn.microsoft.com/Forums/Lync/en-US/e321cb3c-462a-4b16-b7e4-febdb3d0c7d6/windows-10-pairing-a-ble-device-from-code?forum=wdk&prof=required

用户 steno916 似乎已经想出了如何处理这个问题，但我无法从他提供的代码中理解他做了什么。

Answer 1

note: while compiling class template member function 'HRESULT Microsoft::WRL::Details::InvokeHelper::Invoke(ABI::Windows::Devices::Bluetooth::Advertisement::IBluetoothLEAdvertisementWatcher *,ABI::Windows::Devices::Bluetooth::Advertisement::IBluetoothLEAdvertisementReceivedEventArgs *)'

模板编译错误消息可能会很痛苦。这个肯定是妈妈的，问题跟HRESULT无关。查看“输出”窗口以阅读完整的错误消息非常重要。这是消息的一部分，提供重要提示以帮助您诊断问题所在。

尽管如此，即使您看了一个小时或一天，仍然看不到它。有时将其编辑下来很有用，将很长的名称替换为较短的名称以降低噪音水平。可能会揭示基本细节，请注意它如何将接口(interface)指针 传递给 Invoke()。因此，回调必须在其签名中同样使用接口(interface)指针。添加两个 I:

HRESULT OnConnectionReceived(IBluetoothLEAdvertisementWatcher* watcher,
                             IBluetoothLEAdvertisementReceivedEventArgs* args) {
    // etc...
}