頭文件：

#pragma once
#include <QWidget>class CFrameLessWidgetBase :public QWidget
{
public:CFrameLessWidgetBase(QWidget* p = nullptr);~CFrameLessWidgetBase() {}protected:bool nativeEvent(const QByteArray& eventType, void* message, long* result) override;private:int m_nBorderWidth = 5;
};

實現：

#include "CFrameLessWidgetBase.h"
#include <qt_windows.h>
#include <windows.h>
#include <windowsx.h>#pragma comment(lib, "user32.lib")
#pragma comment(lib,"dwmapi.lib")CFrameLessWidgetBase::CFrameLessWidgetBase(QWidget* p):QWidget(p)
{this->setWindowFlags(Qt::FramelessWindowHint | Qt::WindowMinMaxButtonsHint);setAttribute(Qt::WA_Hover);   //很重要
}bool CFrameLessWidgetBase::nativeEvent(const QByteArray& eventType, void* message, long* result)
{MSG* param = static_cast<MSG*>(message);switch (param->message){case WM_NCHITTEST:{int nX = GET_X_LPARAM(param->lParam) - this->geometry().x();int nY = GET_Y_LPARAM(param->lParam) - this->geometry().y();/*if (childAt(nX, nY) != nullptr)return QWidget::nativeEvent(eventType, message, result);*/if (nX > m_nBorderWidth && nX < this->width() - m_nBorderWidth &&nY > m_nBorderWidth && nY < this->height() - m_nBorderWidth){if (childAt(nX, nY) != nullptr)return QWidget::nativeEvent(eventType, message, result);}if ((nX > 0) && (nX < m_nBorderWidth))*result = HTLEFT;if ((nX > this->width() - m_nBorderWidth) && (nX < this->width()))*result = HTRIGHT;if ((nY > 0) && (nY < m_nBorderWidth))*result = HTTOP;if ((nY > this->height() - m_nBorderWidth) && (nY < this->height()))*result = HTBOTTOM;if ((nX > 0) && (nX < m_nBorderWidth) && (nY > 0)&& (nY < m_nBorderWidth))*result = HTTOPLEFT;if ((nX > this->width() - m_nBorderWidth) && (nX < this->width())&& (nY > 0) && (nY < m_nBorderWidth))*result = HTTOPRIGHT;if ((nX > 0) && (nX < m_nBorderWidth)&& (nY > this->height() - m_nBorderWidth) && (nY < this->height()))*result = HTBOTTOMLEFT;if ((nX > this->width() - m_nBorderWidth) && (nX < this->width())&& (nY > this->height() - m_nBorderWidth) && (nY < this->height()))*result = HTBOTTOMRIGHT;return true;}}return false;
}

要實現無邊界窗口的設計，只需要集成自這個類就可以了。