chapter28dlg.cpp

有关mfc异常处理方面的知识

// Chapter28Dlg.cpp : implementation file
//

#include "stdafx.h"
#include "Chapter28.h"
#include "Chapter28Dlg.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CAboutDlg dialog used for App About

class CAboutDlg : public CDialog
{
public:
	CAboutDlg();

// Dialog Data
	//{{AFX_DATA(CAboutDlg)
	enum { IDD = IDD_ABOUTBOX };
	//}}AFX_DATA

	// ClassWizard generated virtual function overrides
	//{{AFX_VIRTUAL(CAboutDlg)
	protected:
	virtual void DoDataExchange(CDataExchange* pDX);    // DDX/DDV support
	//}}AFX_VIRTUAL

// Implementation
protected:
	//{{AFX_MSG(CAboutDlg)
	//}}AFX_MSG
	DECLARE_MESSAGE_MAP()
};

CAboutDlg::CAboutDlg() : CDialog(CAboutDlg::IDD)
{
	//{{AFX_DATA_INIT(CAboutDlg)
	//}}AFX_DATA_INIT
}

void CAboutDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	//{{AFX_DATA_MAP(CAboutDlg)
	//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CAboutDlg, CDialog)
	//{{AFX_MSG_MAP(CAboutDlg)
		// No message handlers
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CChapter28Dlg dialog

CChapter28Dlg::CChapter28Dlg(CWnd* pParent /*=NULL*/)
	: CDialog(CChapter28Dlg::IDD, pParent)
{
	//{{AFX_DATA_INIT(CChapter28Dlg)
		// NOTE: the ClassWizard will add member initialization here
	//}}AFX_DATA_INIT
	// Note that LoadIcon does not require a subsequent DestroyIcon in Win32
	m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void CChapter28Dlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	//{{AFX_DATA_MAP(CChapter28Dlg)
		// NOTE: the ClassWizard will add DDX and DDV calls here
	//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CChapter28Dlg, CDialog)
	//{{AFX_MSG_MAP(CChapter28Dlg)
	ON_WM_SYSCOMMAND()
	ON_WM_PAINT()
	ON_WM_QUERYDRAGICON()
	ON_BN_CLICKED(IDC_CATCH_TRY, OnCatchTry)
	ON_BN_CLICKED(IDC_ABNORMAL_TER, OnAbnormalTer)
	ON_BN_CLICKED(IDC_ABNORMAL_TER2, OnAbnormalTer2)
	ON_BN_CLICKED(IDC_DELETE_OBJECT_THROW, OnDeleteObjectThrow)
	ON_BN_CLICKED(IDC_DELETE_EXCEPTION, OnDeleteException)
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CChapter28Dlg message handlers

BOOL CChapter28Dlg::OnInitDialog()
{
	CDialog::OnInitDialog();

	// Add "About..." menu item to system menu.

	// IDM_ABOUTBOX must be in the system command range.
	ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
	ASSERT(IDM_ABOUTBOX < 0xF000);

	CMenu* pSysMenu = GetSystemMenu(FALSE);
	if (pSysMenu != NULL)
	{
		CString strAboutMenu;
		strAboutMenu.LoadString(IDS_ABOUTBOX);
		if (!strAboutMenu.IsEmpty())
		{
			pSysMenu->AppendMenu(MF_SEPARATOR);
			pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
		}
	}

	// Set the icon for this dialog.  The framework does this automatically
	//  when the application's main window is not a dialog
	SetIcon(m_hIcon, TRUE);			// Set big icon
	SetIcon(m_hIcon, FALSE);		// Set small icon
	
	// TODO: Add extra initialization here
	
	return TRUE;  // return TRUE  unless you set the focus to a control
}

void CChapter28Dlg::OnSysCommand(UINT nID, LPARAM lParam)
{
	if ((nID & 0xFFF0) == IDM_ABOUTBOX)
	{
		CAboutDlg dlgAbout;
		dlgAbout.DoModal();
	}
	else
	{
		CDialog::OnSysCommand(nID, lParam);
	}
}

// If you add a minimize button to your dialog, you will need the code below
//  to draw the icon.  For MFC applications using the document/view model,
//  this is automatically done for you by the framework.

void CChapter28Dlg::OnPaint() 
{
	if (IsIconic())
	{
		CPaintDC dc(this); // device context for painting

		SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);

		// Center icon in client rectangle
		int cxIcon = GetSystemMetrics(SM_CXICON);
		int cyIcon = GetSystemMetrics(SM_CYICON);
		CRect rect;
		GetClientRect(&rect);
		int x = (rect.Width() - cxIcon + 1) / 2;
		int y = (rect.Height() - cyIcon + 1) / 2;

		// Draw the icon
		dc.DrawIcon(x, y, m_hIcon);
	}
	else
	{
		CDialog::OnPaint();
	}
}

// The system calls this to obtain the cursor to display while the user drags
//  the minimized window.
HCURSOR CChapter28Dlg::OnQueryDragIcon()
{
	return (HCURSOR) m_hIcon;
}

void CChapter28Dlg::Div_Cus(int numer, int denom)
{
	//除法运算中除数为0时将抛出异常
	if(denom==0)
	{
		TRACE("CChapter28Dlg::Div_Cus抛出异常\n");
		throw 1;
	}
	else
	{
		//除法运算
		numer=numer/denom; 
		TRACE("正常退出CChapter28Dlg::Div_Cus\n");
		return;
	}

}


void CChapter28Dlg::OnCatchTry() 
{
	// TODO: Add your control notification handler code here
	CString strFile="myvc.dat";
	CString strMessage;
	TRY
	{
		//从磁盘文件构造CFile对象，可能抛出异常
		CFile file(strFile,CFile::modeRead);
	}
	CATCH(CFileException, e)
	{
		switch(e->m_cause)
		{
		case CFileException::fileNotFound:
			{
			strMessage.Format("打开文件时发生异常(TRY/CATCH)：\
				在指定位置没有找到文件%s\n",strFile);
			AfxMessageBox(strMessage);
			//删除异常
			e->Delete();
			break;
			}
		default:
			break;
		}
	}
	END_CATCH
		
}

void CChapter28Dlg::OnAbnormalTer() 
{
	// TODO: Add your control notification handler code here
	CPen* pPen=new CPen();
	try
	{
		//......其他处理过程
		Div_Cus(100,0);
	}
	catch(...)
	{
		AfxMessageBox("捕获到异常");
		
	}
	//退出前销毁堆上创建的对象
	TRACE("退出前销毁堆上创建的CPen对象");
	delete pPen;
}

void CChapter28Dlg::OnAbnormalTer2() 
{
	// TODO: Add your control notification handler code here
	CPen* pPen=new CPen();
	//......其他处理过程
	Div_Cus(100,0);
	delete pPen;
}

void CChapter28Dlg::OnDeleteObjectThrow() 
{
	// TODO: Add your control notification handler code here
	CBrush* pBrush=new CBrush();
	try
	{
		//......其他处理过程
		//此函数调用可能引发异常
		Div_Cus(100,0);
	}
	catch(...)
	{
		//在继续传递异常前首先删除CBrush对象
		TRACE("在继续传递异常前首先删除CBrush对象");
		delete pBrush;
		throw;
		
	}
	//退出前销毁堆上创建的对象
	TRACE("退出前销毁堆上创建的CBrush对象");
	delete pBrush;
}

void CChapter28Dlg::OnDeleteException() 
{
	// TODO: Add your control notification handler code here
	CString strFile="myvc.dat";
	CString strMessage;
	try
	{
		//从磁盘文件构造CFile对象，可能抛出异常
		CFile file(strFile,CFile::modeRead);
	}
	catch(CFileException* e)
	{
		switch(e->m_cause)
		{
		case CFileException::fileNotFound:
			{
			strMessage.Format("打开文件时发生异常(try/catch)：\
				在指定位置没有找到文件%s\n",strFile);
			AfxMessageBox(strMessage);
			TRACE("即将删除捕获到的异常对象CFileException::fileNotFound\n");
			AfxMessageBox("即将删除捕获到的异常对象CFileException::fileNotFound");
			//删除异常对象
			e->Delete();
			TRACE("成功删除捕获到的异常对象CFileException::fileNotFound\n");
			AfxMessageBox("成功删除捕获到的异常对象CFileException::fileNotFound");
			break;
			}
		case CFileException::invalidFile:
			{
			strMessage.Format("打开文件时发生异常(try/catch)：\
				文件%无效\n",strFile);
			AfxMessageBox(strMessage);
			TRACE("即将删除捕获到的异常对象CFileException::invalidFile\n");
			AfxMessageBox("即将删除捕获到的异常对象CFileException::invalidFile");
			//删除异常对象
			e->Delete();
			TRACE("成功删除捕获到的异常对象CFileException::invalidFile\n");
			AfxMessageBox("成功删除捕获到的异常对象CFileException::invalidFile");
			break;
			}
		default:
			break;
		}
	}
	catch(CMemoryException* ee)
	{
		//其他处理过程
	}
	catch(CException* eee)
	{
		//其他处理过程
	}
}
/*//查看异常内容，第20章的工程Chapter20中CRightListView类的成员函数，稍作编辑
void CRightListView::AddToList(CSongRecordSet &db,CString& strSql)
{
	CListCtrl& listCtrl=GetListCtrl();
	listCtrl.DeleteAllItems();
	//将数据库中记录插入
	try
	{
	if(db.IsOpen())
	db.Close();
	//设置查询条件
	db.m_strFilter=strSql;
	//执行查询
	db.Open(CRecordset::snapshot,NULL,CRecordset::none);
	…
	}
	//意外捕获
	catch(CDBException* e)
	{
	//提示用户异常
	CString strView;
	strView.Format("异常原因：%s\n错误代码：%d",e->m_strError,e->m_nRetCode);
	AfxMessageBox(strView);
	e->Delete();
	//提示异常原因
	TRACE("%s",strView);
	return;
	}
}

*/