《windows核心编程》笔记（一）

1,windows对程序错误的处理，

intAPIENTRY_tWinMain(HINSTANCEhInstance,HINSTANCEhPrevInstance,LPTSTRlpCmdLine,intnCmdShow)
{
LPVOIDlpMsgBuf;
HANDLEhFile=::CreateFile(_T("C://12.txt"),0,0,NULL,OPEN_EXISTING,0,NULL);//打开文件
if(INVALID_HANDLE_VALUE==hFile)
{//文件不存在
FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS,NULL,GetLastError(),0,(LPTSTR)&lpMsgBuf,0,NULL);
MessageBox(NULL,(LPCWSTR)lpMsgBuf,_T("错误信息"),MB_OK|MB_ICONINFORMATION);
LocalFree(lpMsgBuf);
}
return0;
}

调试时，在Watch窗口输入“@err,hr”,就可以显示线程的最后错误代码的号码和该错误的描述信息。

VC6.0还带了一个实用小程序，可以用来将错误代码转换为相应的文本描述信息。
<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

书中给出了一个模仿VC6自带的那个Error Lookup实用程序的示例：

#defineESM_POKECODEANDLOOKUP(WM_USER+100)//用户自定义消息
constTCHARg_szAppName[]=TEXT("ErrorShow");

BOOLDlg_OnInitDialog(HWNDhwnd,HWNDhwndFocus,LPARAMlParam)
{

chSETDLGICONS(hwnd,IDI_ERRORSHOW);//设置图标

//Don'taccepterrorcodesmorethan5digitslong
Edit_LimitText(GetDlgItem(hwnd,IDC_ERRORCODE),5);//限制输入字符长度最大为

//Lookupthecommand-linepassederrornumber
SendMessage(hwnd,ESM_POKECODEANDLOOKUP,lParam,0);//发送初始错误代码消息
return(TRUE);
}

voidDlg_OnCommand(HWNDhwnd,intid,HWNDhwndCtl,UINTcodeNotify){

switch(id)
{

caseIDCANCEL:
EndDialog(hwnd,id);//关闭对话框窗口
break;

caseIDC_ALWAYSONTOP://始终在最前
SetWindowPos(hwnd,IsDlgButtonChecked(hwnd,IDC_ALWAYSONTOP)?HWND_TOPMOST:HWND_NOTOPMOST,0,0,0,0,SWP_NOMOVE|SWP_NOSIZE);
break;

caseIDC_ERRORCODE:
EnableWindow(GetDlgItem(hwnd,IDOK),Edit_GetTextLength(hwndCtl)>0);//设置“lookup"按钮是否enable
break;

caseIDOK:
//Gettheerrorcode
DWORDdwError=GetDlgItemInt(hwnd,IDC_ERRORCODE,NULL,FALSE);//获取错误代码号码

HLOCALhlocal=NULL;//Bufferthatgetstheerrormessagestring

//UsethedefaultsystemlocalesincewelookforWindowsmessages.
//Note:thisMAKELANGIDcombinationhas0asvalue
DWORDsystemLocale=MAKELANGID(LANG_NEUTRAL,SUBLANG_NEUTRAL);//本地语言

//Gettheerrorcode'stextualdescription
BOOLfOk=FormatMessage(
FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS|
FORMAT_MESSAGE_ALLOCATE_BUFFER,
NULL,dwError,systemLocale,
(PTSTR)&hlocal,0,NULL);

if(!fOk)
{
//Isitanetwork-relatederror?
HMODULEhDll=LoadLibraryEx(TEXT("netmsg.dll"),NULL,
DONT_RESOLVE_DLL_REFERENCES);

if(hDll!=NULL)
{
fOk=FormatMessage(
FORMAT_MESSAGE_FROM_HMODULE|FORMAT_MESSAGE_IGNORE_INSERTS|
FORMAT_MESSAGE_ALLOCATE_BUFFER,
hDll,dwError,systemLocale,
(PTSTR)&hlocal,0,NULL);
FreeLibrary(hDll);
}
}

if(fOk&&(hlocal!=NULL))
{
SetDlgItemText(hwnd,IDC_ERRORTEXT,(PCTSTR)LocalLock(hlocal));
LocalFree(hlocal);
}
else
{
SetDlgItemText(hwnd,IDC_ERRORTEXT,TEXT("Notextfoundforthiserrornumber."));
}
break;
}
}

INT_PTRWINAPIDlg_Proc(HWNDhwnd,UINTuMsg,WPARAMwParam,LPARAMlParam)
{

switch(uMsg)
{
chHANDLE_DLGMSG(hwnd,WM_INITDIALOG,Dlg_OnInitDialog);//初始化处理
chHANDLE_DLGMSG(hwnd,WM_COMMAND,Dlg_OnCommand);//命令处理

caseESM_POKECODEANDLOOKUP:
SetDlgItemInt(hwnd,IDC_ERRORCODE,(UINT)wParam,FALSE);//控件上设置错误代码
FORWARD_WM_COMMAND(hwnd,IDOK,GetDlgItem(hwnd,IDOK),BN_CLICKED,PostMessage);//模拟按钮点击事件
SetForegroundWindow(hwnd);//设置为最前的窗口
break;
}

return(FALSE);
}

intWINAPI_tWinMain(HINSTANCEhinstExe,HINSTANCE,PTSTRpszCmdLine,int)
{

HWNDhwnd=FindWindow(TEXT("#32770"),TEXT("ErrorShow"));//寻址窗口
if(IsWindow(hwnd))
{//已经存在
//Aninstanceisalreadyrunning,activateitandsenditthenew#
SendMessage(hwnd,ESM_POKECODEANDLOOKUP,_ttoi(pszCmdLine),0);
}
else
{//新窗口
DialogBoxParam(hinstExe,MAKEINTRESOURCE(IDD_ERRORSHOW),NULL,Dlg_Proc,_ttoi(pszCmdLine));
}
return(0);
}

这里用到了几个宏定义，下面这个是用来指定消息处理函数的

//ThenormalHANDLE_MSGmacroinWindowsX.hdoesnotworkproperlyfordialog
//boxesbecauseDlgProcreturnsaBOOLinsteadofanLRESULT(like
//WndProcs).ThischHANDLE_DLGMSGmacrocorrectstheproblem:
#definechHANDLE_DLGMSG(hWnd,message,fn)/
case(message):return(SetDlgMsgResult(hWnd,uMsg,/
HANDLE_##message((hWnd),(wParam),(lParam),(fn))))

下面这个是用来为窗口设置大/小图标

//Setsthedialogboxicons
inlinevoidchSETDLGICONS(HWNDhWnd,intidi)
{
SendMessage(hWnd,WM_SETICON,ICON_BIG,(LPARAM)
LoadIcon((HINSTANCE)GetWindowLongPtr(hWnd,GWLP_HINSTANCE),
MAKEINTRESOURCE(idi)));
SendMessage(hWnd,WM_SETICON,ICON_SMALL,(LPARAM)
LoadIcon((HINSTANCE)GetWindowLongPtr(hWnd,GWLP_HINSTANCE),
MAKEINTRESOURCE(idi)));
}