DVD出租系统【6】完成DVD系统

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DVD出租系统【6】完成DVD系统

本节最后目的：完成出租DVD的功能，删除出租记录功能。

1、继续打开上节的工程，双击出租DVD按钮，进行代码修改。

2、打开CRentDVD类进行初始化代码添加，当打开出租DVD时候，自动读取数据库数据，将函数添加到初始化函数中。

void CRentDVD::InitListCtrl()
{
	HRESULT hr;
	_RecordsetPtr pDVDRecordset;
	hr = pDVDRecordset.CreateInstance(__uuidof(Recordset));
	if (FAILED(hr)) {
		MessageBox(_T("创建记录集对象失败."));
		return;
	}
	try
	{
		//直接把表明作为第一个参数，记录集中是该表中的所有记录，最后一个参数传递 adCmdTable
		pDVDRecordset->Open(_variant_t("tbDVDInfo"), m_pConnection.GetInterfacePtr(), adOpenDynamic, adLockOptimistic, adCmdTable);
	}
	catch (_com_error *e)
	{
		MessageBox(e->ErrorMessage());
		return;
	}

	_variant_t var;
	CString strValue;
	int curItem = 0;

	try {
		while (!pDVDRecordset->GetadoEof()) {
			var = pDVDRecordset->Fields->GetItem(long(0))->GetValue();
			if (var.vt != NULL)
				strValue = (LPCTSTR)_bstr_t(var);
			m_DVDInfoList.InsertItem(curItem, strValue);

			var = pDVDRecordset->Fields->GetItem(long(1))->GetValue();
			if (var.vt != NULL)
				strValue = (LPCTSTR)_bstr_t(var);
			m_DVDInfoList.SetItemText(curItem, 1, strValue);

			var = pDVDRecordset->Fields->GetItem(long(2))->GetValue();
			if (var.vt != NULL)
				strValue = (LPCTSTR)_bstr_t(var);
			m_DVDInfoList.SetItemText(curItem, 2, strValue);

			var = pDVDRecordset->Fields->GetItem(long(3))->GetValue();
			if (var.vt != NULL)
				strValue = (LPCTSTR)_bstr_t(var);
			m_DVDInfoList.SetItemText(curItem, 3, strValue);

			pDVDRecordset->MoveNext();
			curItem++;
		}
	}
	catch (_com_error *e)
	{
		MessageBox(e->ErrorMessage());
		return;
	}

	pDVDRecordset->Close();
	pDVDRecordset = NULL;
}

3、 双击租给他按钮，编辑代码：

void CRentDVD::OnBnClickedButtonRentit()
{
	// TODO: 在此添加控件通知处理程序代码
	UpdateData(TRUE);
	CString strDVDID, strDate;

	GetDlgItem(IDC_DATE_RENT)->GetWindowText(strDate);

	int sel = m_DVDInfoList.GetSelectionMark();
	if (sel < 0)
	{
		MessageBox(_T("请选择要租借的DVD."));
		return;
	}
	else {
		strDVDID = m_DVDInfoList.GetItemText(sel, 0);
	}

	CString strLeftNum = m_DVDInfoList.GetItemText(sel, 2);
	int iLeftNum = _ttoi(strLeftNum);
	if (iLeftNum <= 0)
	{
		MessageBox(_T("不好意思，该DVD已经没有存货了."));
		return;
	}

	if (m_rentName.IsEmpty())
	{
		MessageBox(_T("请填写租借人的姓名."), _T("提示"), MB_OK | MB_ICONINFORMATION);
		m_editRentName.SetFocus();
		return;
	}

	BOOL bRet = RentDVDByRecordset(strDVDID, m_rentName, strDate);   //增加数据方法一
	//BOOL bRet = RentDVDByCommand(strDVDID, m_rentName, strDate);   //增加数据方法二
	if (TRUE == bRet) {
		// m_bRent = TRUE;
		CDVDRentDlg *pParentWnd = (CDVDRentDlg *)GetParent();
		pParentWnd->ModDVDNum(strDVDID, -1);
		MessageBox(_T("租借成功！"), _T("提示"), MB_OK);
	}
}

4、增加数据添加函数：

//增加数据方法一
BOOL CRentDVD::RentDVDByRecordset(CString& strDVDID, CString& strRentName, CString& strRentDate)
{
	BOOL bRet = FALSE;
	_RecordsetPtr pRentRecordset;
	pRentRecordset.CreateInstance(__uuidof(Recordset));
	try {
		HRESULT hr = pRentRecordset->Open(
			_T("select * from tbRentInfo"),
			m_pConnection.GetInterfacePtr(),
			adOpenDynamic,
			adLockOptimistic,
			adCmdText);

		if (SUCCEEDED(hr))
		{
			pRentRecordset->AddNew();
			pRentRecordset->PutCollect("sDVDID", _variant_t(strDVDID));
			pRentRecordset->PutCollect("sName", _variant_t(strRentName));
			pRentRecordset->PutCollect("sDate", _variant_t(strRentDate));
			pRentRecordset->Update();
			bRet = TRUE;
		}
	}
	catch (_com_error *e) {
		MessageBox(e->ErrorMessage());
	}

	pRentRecordset->Close();
	pRentRecordset = NULL;
	return bRet;
}

//增加数据方法二
BOOL CRentDVD::RentDVDByCommand(CString& strDVDID, CString& strRentName, CString& strRentDate)
{
	BOOL bRet = FALSE;
	_CommandPtr pCommand;
	pCommand.CreateInstance(__uuidof(Command));
	pCommand->ActiveConnection = m_pConnection;

	CString strSQL;
	strSQL.Format(_T("insert into tbRentInfo(sDVDID,sName,sDate) values(\'%s\',\'%s\',\'%s\')"), strDVDID, strRentName, strRentDate);
	pCommand->CommandText = _bstr_t(strSQL);

	try {
		HRESULT hr = pCommand->Execute(NULL, NULL, adCmdText);
		if (SUCCEEDED(hr)) {
			bRet = TRUE;
		}

	}
	catch (_com_error *e) {
		MessageBox(e->ErrorMessage());
	}

	return bRet;
}

5、注意，新的类初始化一定要初始化新传递的参数：

6、回到主界面，双击删除出租记录，编辑代码：

void CDVDRentDlg::OnBnClickedButtonDel()
{
	// TODO: 在此添加控件通知处理程序代码
	int sel = m_rentInfoList.GetSelectionMark();
	if (sel >= 0 && MessageBox(_T("确定删除这条记录？"), _T("提示"), MB_YESNO) == IDYES)
	{
		CString rentID = m_rentInfoList.GetItemText(sel, 0);
		CString dvdName = m_rentInfoList.GetItemText(sel, 2);
		DeleteRecord(rentID, dvdName);
		m_rentInfoList.DeleteItem(sel);
	}
	else if (sel < 0) {
		MessageBox(_T("请先选中一条记录再进行删除操作。"));
	}
}

7、增加删除出租记录函数所用的函数：

void  CDVDRentDlg::DeleteRecord(CString& rentID, CString& dvdName)
{
	_bstr_t vSQL;
	vSQL = _T("delete from tbRentInfo where sID=") + rentID;
	_variant_t RecordsAffected;
	try
	{
		HRESULT hr = m_pConnection->Execute(_bstr_t(vSQL), &RecordsAffected, adCmdText);
		if (SUCCEEDED(hr))
		{
			CString strDVDID = QueryDVDId(dvdName);
			ModDVDNum(strDVDID,1);
		}
	}
	catch (_com_error *e)
	{
		MessageBox(e->ErrorMessage());
		return;
	}
}

BOOL CDVDRentDlg::ModDVDNum(CString & strDVDID,int SDVDNum)
{
	HRESULT hr;
	_RecordsetPtr pRentRecordset;
	hr = pRentRecordset.CreateInstance(__uuidof(Recordset));
	if (FAILED(hr)) {
		MessageBox(_T("创建记录集对象失败."));
		return FALSE;
	}
	try
	{
		CString strSQL;
		strSQL = _T("SELECT * FROM tbDVDInfo where sDVDID=" + strDVDID);
		hr = pRentRecordset->Open(_variant_t(strSQL), m_pConnection.GetInterfacePtr(), adOpenDynamic, adLockOptimistic, adCmdText);
		if (SUCCEEDED(hr)) {
			_variant_t var;
			CString strValue;
			var = pRentRecordset->GetCollect(_T("sNum"));
			if (var.vt != NULL) {
				strValue = (LPCTSTR)_bstr_t(var);
				int num;
				num = _ttoi(strValue);
				num = num + (SDVDNum);
				CString DVDNumStr;
				DVDNumStr.Format(_T("%d"),num);
				BOOL bRet = FALSE;
				_CommandPtr pCommand;
				pCommand.CreateInstance(__uuidof(Command));
				pCommand->ActiveConnection = m_pConnection;
				CString strSQL;
				strSQL.Format(_T("update tbDVDInfo set sNum=%s where sDVDID=(\'%s\')"), DVDNumStr,strDVDID);
				MessageBox(strSQL);
				pCommand->CommandText = _bstr_t(strSQL);

				try {
					HRESULT hr = pCommand->Execute(NULL, NULL, adCmdText);
					if (SUCCEEDED(hr)) {
						bRet = TRUE;
					}
					return bRet;

				}
				catch (_com_error *e) {
					MessageBox(e->ErrorMessage());
				}
			}
		}
		else {
			MessageBox(_T("打开结果记录集失败."));
			return FALSE;
		}
	}
	catch (_com_error &e) {
		MessageBox(e.ErrorMessage());
		return FALSE;
	}
	pRentRecordset->Close();
	pRentRecordset = NULL;
}

8、至此功能基本完成，运行图如下：

9、文中有一些小细节没有说到，有问题的可以留言。工程地址：

链接：https://pan.baidu.com/s/1d8R9tBBnRvZwvEULuUGt7A 
提取码：qh2y (本工程为完整性工程，索要密码请关注作者并联系作者QQ1967449842)