[Error] MyUnit.pas(LL): Undeclared identifier: 'NNNN'

MyUnit.pas	源文件的名称.
LL	第几行.
NNNN	提示的标识名.

• 常见的错误是由于拼写错误造成，例子如下：

• 另一种是代码正确，但要用到的单元没有包含进去。如：

Type	Unit
_Stream	ADODB_TLB
akTop, akLeft, akRight, akBottom	Controls
Application (the variable not a type)	Forms
Beep	SysUtils or Windows (different functions)
CGID_EXPLORER	ShlObj
CN_BASE	Controls
CoInitialize	ActiveX
CopyFile	Windows
CoUnInitialize	ActiveX
CreateComObject	ComObj
CreateOleObject	ComObj
Date	SysUtils
DeleteFile	SysUtils or Windows (different versions)
DispatchInvokeError	ComObj
DWORD	Windows
EDatabaseError	DB
EncodeDateTime	DateUtils
EnumWindows	Windows
EOleError	ComObj
EOleException	ComObj
EOleSysError	ComObj
Exception	SysUtils
ExtractFileName	SysUtils
FileExists	SysUtils
FileOpen	SysUtils
FILETIME	Windows
FindFirst	SysUtils
FindFirstFile	Windows
FindWindow	Windows
FlushFileBuffers	Windows
fmOpenRead	SysUtils
fmShareDenyWrite	SysUtils
Format	SysUtils
FormatDateTime	SysUtils
FreeAndNil	SysUtils
fsBold	Graphics
ftWideString	DB
ftString	DB
GetCurrentProcessId	Windows
GetEnvironmentVariable	SysUtils or Windows (different versions)
GetFileAttributes	Windows
GetFileVersionInfoSize	Windows
GetWindowLong	Windows
GetStdHandle	Windows
HDC	Windows
HFont	Windows
HINTERNET	WinInet
HKEY_CURRENT_USER	Windows
IHTMLDocument2	MSHTML or MSHTML_TLB
IHTMLElement	MSHTML or MSHTML_TLB
IHTMLEventObj	MSHTML or MSHTML_TLB
IID_IWebBrowser2	SHDocVw or SHDocVw_TLB
IMessage	CDO_TLB
InternetClosehandle	WinInet
InternetOpenUrl	WinInet
InternetReadFile	WinInet
IntToHex	SysUtils
IntToStr	SysUtils
IOleCommandTarget	ActiveX
IOleContainer	ActiveX
IPersistStreamInit	ActiveX
IsSameDay	DateUtils
IStream	ActiveX
IWebBrowser2	SHDocVw or SHDocVw_TLB
LockWindowUpdate	Windows
Log10	Math
LowerCase	SysUtils
LPSTR	Windows
MAX_PATH	Windows
MessageBox	Windows
MessageDlg	Dialogs
MB_YESNO, MB_OK etc	Windows
MinutesBetween	DateUtils
Now	SysUtils
OleInitialize	ActiveX
OleUninitialize	ActiveX
PItemIDList	ShlObj
POleCmd	ActiveX
POleCmdText	ActiveX
PostMessage	Windows
PosX	StrUtils
QueryHighPerformanceCounter	Windows
QueryPerformanceCounter	Windows
ReverseString	StrUtils
RoundTo	Math
SendMessage	Windows
SetForegroundWindow	Windows
ShellExecute	ShellAPI
ShellExecuteEx	ShellAPI
SHGetFileInfo	ShellAPI
SHFILEINFO	ShellAPI
ShowMessage	Dialogs
Sleep	SysUtils
StrAlloc	SysUtils
StrPas	SysUtils
StrToDate	SysUtils
StrToInt	SysUtils
StrToIntDef	SysUtils
TAdoConnection	ADODB
TAdoQuery	ADODB
TAlign	Controls
TAlignment	Classes
TAnchors	Controls
TBitmap	Graphics
TBlobStream	DBTables
TCanvas	Graphics
TClientSocket	ScktComp
TComboBox	StdCtrls
TComponent	Classes
TControl	Controls or QControls
TCriticalSection	SyncObjs
TField	DB
TFieldType	DB
TFileName	SysUtils
TFileStream	Classes
TForm	Forms
TFrame	Forms
TGroupBox	StdCtrls
TIID	ActiveX
TIniFile	IniFiles
TJPEGImage	Jpeg
TLabel	StdCtrls
TList	Classes
TMemo	StdCtrls
TMemoryStream	Classes
TMouseButton	Controls
TNofityEvent	Classes
TObjectList	Contnrs
TOSVersionInfo	Windows
TPanel	ExtCtrls
TPoint	Types
TProcessEntry32	TlHelp32
TProgressBar	ComCtrls or QComCtrls
TRadioButton	StdCtrls
TRadioGroup	ExtCtrls
TRect	Types
TRegistry	Registry
Trim	SysUtils
TRoundToRange	Math
TSearchRec	SysUtils
TSize	Windows
TSocketAddrIn	Winsock
TStaticText	StdCtrls
TStream	Classes
TStringList	Classes
TStrings	Classes
TStringStream	Classes
TSystemTime	Windows
TTable	DBTables
TTabSheet	ComCtrls
TThread	Classes
TTreeNode	ComCtrls
TWebBrowser	SHDocVw or SHDocVw_TLB
TWinSocketStream	ScktComp
TWMCommand	Messages
Unassigned	Variants
VarArrayCreate	Variants
VarArrayOf	Variants
VirtualProtect	Windows
WM_USER	Messages
YearOf	DateUtils