在c++中获取错误命名空间“std”没有成员“towstring”如何修复?

错误在这一行:

std::wstring xml = L"<pitch absmiddle='" + std::to_wstring(pitch) + L"'>Pitch Adjust</pitch>";

错误是:命名空间“std”没有成员“to_wstring”

我还收到两个错误:'to_wstring':不是'std'的成员 “to_wstring”:未找到标识符

我试图在visual studio中更改C/C++中的应用程序属性>语言>C++语言标准转换为ISO C++20标准(/std:C++20),但在单击应用并确定并重建后,错误仍然存在。所以我试着把它改成17,也改成14,但错误仍然存在。

属性设置的屏幕截图:

以下是任何情况下的完整代码:

#include "pch.h"
#include "WindowsVoice.h"
#include <sapi.h>

namespace WindowsVoice {

    static ISpVoice* pVoice = NULL;  // Global voice pointer

    void speechThreadFunc()
    {
        if (FAILED(::CoInitializeEx(NULL, COINITBASE_MULTITHREADED)))
        {
            theStatusMessage = L"Failed to initialize COM for Voice.";
            return;
        }

        HRESULT hr = CoCreateInstance(CLSID_SpVoice, NULL, CLSCTX_ALL, IID_ISpVoice, (void**)&pVoice);
        if (!SUCCEEDED(hr))
        {
            theStatusMessage = L"Failed to create Voice instance.";
            return;
        }
        theStatusMessage = L"Speech ready.";

        SPVOICESTATUS voiceStatus;
        wchar_t* priorText = nullptr;
        while (!shouldTerminate)
        {
            pVoice->GetStatus(&voiceStatus, NULL);
            if (voiceStatus.dwRunningState == SPRS_IS_SPEAKING)
            {
                if (priorText == nullptr)
                    theStatusMessage = L"Error: SPRS_IS_SPEAKING but text is NULL";
                else
                {
                    theStatusMessage = L"Speaking: ";
                    theStatusMessage.append(priorText);
                    if (!theSpeechQueue.empty())
                    {
                        theMutex.lock();
                        if (lstrcmpW(theSpeechQueue.front(), priorText) == 0)
                        {
                            delete[] theSpeechQueue.front();
                            theSpeechQueue.pop_front();
                        }
                        theMutex.unlock();
                    }
                }
            }
            else
            {
                theStatusMessage = L"Waiting.";
                if (priorText != NULL)
                {
                    delete[] priorText;
                    priorText = NULL;
                }
                if (!theSpeechQueue.empty())
                {
                    theMutex.lock();
                    priorText = theSpeechQueue.front();
                    theSpeechQueue.pop_front();
                    theMutex.unlock();
                    pVoice->Speak(priorText, SPF_IS_XML | SPF_ASYNC, NULL);
                }
            }
            Sleep(50);
        }
        pVoice->Pause();
        pVoice->Release();

        theStatusMessage = L"Speech thread terminated.";
    }

    void addToSpeechQueue(const char* text)
    {
        if (text)
        {
            int len = strlen(text) + 1;
            wchar_t* wText = new wchar_t[len];

            memset(wText, 0, len);
            ::MultiByteToWideChar(CP_UTF8, NULL, text, -1, wText, len);

            theMutex.lock();
            theSpeechQueue.push_back(wText);
            theMutex.unlock();
        }
    }

    void clearSpeechQueue()
    {
        theMutex.lock();
        theSpeechQueue.clear();
        theMutex.unlock();
    }

    void initSpeech()
    {
        shouldTerminate = false;
        if (theSpeechThread != nullptr)
        {
            theStatusMessage = L"Windows Voice thread already started.";
            return;
        }
        theStatusMessage = L"Starting Windows Voice.";
        theSpeechThread = new std::thread(WindowsVoice::speechThreadFunc);
    }

    void destroySpeech()
    {
        if (theSpeechThread == nullptr)
        {
            theStatusMessage = L"Speech thread already destroyed or not started.";
            return;
        }
        theStatusMessage = L"Destroying speech.";
        shouldTerminate = true;
        theSpeechThread->join();
        theSpeechQueue.clear();
        delete theSpeechThread;
        theSpeechThread = nullptr;
        CoUninitialize();
        theStatusMessage = L"Speech destroyed.";
    }

    void statusMessage(char* msg, int msgLen)
    {
        size_t count;
        wcstombs_s(&count, msg, msgLen, theStatusMessage.c_str(), msgLen);
    }

    // New Functions for Rate, Volume, and Pitch
    void setSpeechRate(int rate)
    {
        if (pVoice)
            pVoice->SetRate(rate);
    }

    void setSpeechVolume(int volume)
    {
        if (pVoice)
            pVoice->SetVolume(volume);
    }

    void setSpeechPitch(int pitch)
    {
        if (pVoice)
        {
            std::wstring xml = L"<pitch absmiddle='" + std::to_wstring(pitch) + L"'>Pitch Adjust</pitch>";
            pVoice->Speak(xml.c_str(), SPF_IS_XML | SPF_ASYNC, NULL);
        }
    }
}

BOOL APIENTRY DllMain(HMODULE, DWORD ul_reason_for_call, LPVOID)
{
    switch (ul_reason_for_call)
    {
    case DLL_PROCESS_ATTACH:
    case DLL_THREAD_ATTACH:
    case DLL_THREAD_DETACH:
    case DLL_PROCESS_DETACH:
        break;
    }

    return TRUE;
}