Iczelion's Win32 Assembly Tutorial 34: RichEdit Control: More Text Operations

Tutorial 34: RichEdit Control: More Text Operations

Tutorial 35: RichEdit Control: Syntax Hilighting

You'll learn more about text operations under RichEdit control. Specifically, you'll know how to search for/replace text, jumping to specific line number.

Download the example.

Theory

Searching for Text

There are several text operations under RichEdit control. Searching for text is one such operation. Searching for text is done by sending EM_FINDTEXT or EM_FINDTEXTEX. These messages has a small difference.

EM_FINDTEXT

wParam Search options. Can be any combination of the values in the table below. These options are identical for both EM_FINDTEXT and EM_FINDTEXTEX.

FR_DOWN If this flag is specified, the search starts from the end of the current selection to the end of the text in the control (downward). This flag has effect only for RichEdit 2.0 or later: this behavior is the default for richedit 1.0. The default behavior of RichEdit 2.0 or later is to search from the END of the current selection to the beginning of the text (upward).

In summary, if you use RichEdit 1.0, you can't do anything about the search direction: it always searches downward. If you use RichEdit 2.0 and you want to search downward, you must specify this flag else the search would be upward.

FR_MATCHCASE If this flag is specified, the search is case-sensitive.

FR_WHOLEWORD If this flag is set, the search finds the whole word that matches the specified search string.

Actually, there are a few more flags but they are relevant to non-English languages.

lParam pointer to the FINDTEXT structure. FINDTEXT STRUCT chrg CHARRANGE <> lpstrText DWORD ? FINDTEXT ENDS
chrg is a CHARRANGE structure which is defined as follows: CHARRANGE STRUCT cpMin DWORD ? cpMax DWORD ? CHARRANGE ENDS

cpMin contains the character index of the first character in the character array (range).

cpMax contains the character index of the character immediately following the last character in the character array.

In essence, to search for a text string, you have to specify the character range in which to search. The meaning of cpMin and cpMax differ according to whether the search is downward or upward. If the search is downward, cpMin specifies the starting character index to search in and cpMax the ending character index. If the search is upward, the reverse is true, ie. cpMin contains the ending character index while cpMax the starting character index.

lpstrText is the pointer to the text string to search for.

EM_FINDTEXT returns the character index of the first character in the matching text string in the richedit control. It returns -1 if no match is found.

EM_FINDTEXTEX

wParam the search options. Same as those of EM_FINDTEXT.
lParam pointer to the FINDTEXTEX structure. FINDTEXTEX STRUCT chrg CHARRANGE <> lpstrText DWORD ? chrgText CHARRANGE <> FINDTEXTEX ENDS
The first two members of FINDTEXTEX are identical to those of FINDTEXT structure. chrgText is a CHARRANGE structure that will be filled with the starting/ending characterindices if a match is found.

The return value of EM_FINDTEXTEX is the same as that of EM_FINDTEXT.

The difference between EM_FINDTEXT and EM_FINDTEXTEX is that the FINDTEXTEX structure has an additional member, chrgText, which will be filled with the starting/ending character indices if a match is found. This is convenient if we want to do more text operations on the string.

Replace/Insert Text

RichEdit control provides EM_SETTEXTEX for replacing/inserting text. This message combines the functionality of WM_SETTEXT and EM_REPLACESEL. It has the following syntax:

EM_SETTEXTEX

wParam pointer to SETTEXTEX structure. SETTEXTEX STRUCT flags DWORD ? codepage DWORD ? SETTEXTEX ENDS
flags can be the combination of the following values:
- ST_DEFAULT Deletes the undo stack, discards rich-text formatting, replaces all text.
- ST_KEEPUNDO Keeps the undo stack
- ST_SELECTION Replaces selection and keeps rich-text formatting

codepage is the constant that specifies the code page you want to text to be. Usually, we simply use CP_ACP.

Text Selection

We can select the text programmatically with EM_SETSEL or EM_EXSETSEL. Either one works fine. Choosing which message to use depends on the available format of the character indices. If they are already stored in a CHARRANGE structure, it's easier to use EM_EXSETSEL.

EM_EXSETSEL

wParam not used, must be 0.
lParam pointer to a CHARRANGE structure that contains the character range to be selected.

Event Notification

In the case of a multiline edit control, you have to subclass it in order to obtain the input messages such as mouse/keyboard events. RichEdit control provides a better scheme that will notify the parent window of such events. In order to register for notifications, the parent window sends EM_SETEVENTMASK message to the RichEdit control, specifying which events it's interested in. EM_SETEVENTMASK has the following syntax:

EM_SETEVENTMASK

wParam not used, must be 0.
lParam event mask value. It can be the combination of the flags in the table below.
- ENM_CHANGE Sends EN_CHANGE notifications.
- ENM_CORRECTTEXT Sends EN_CORRECTTEXT notifications.
- ENM_DRAGDROPDONE Sends EN_DRAGDROPDONE notifications.
- ENM_DROPFILES Sends EN_DROPFILES notifications.
- ENM_KEYEVENTS Sends EN_MSGFILTER notifications for keyboard events.
- ENM_LINK rich edit 2.0 and later:
  Sends EN_LINK notifications when the mouse pointer is over text that has the cfe_link and one of several mouse actions is performed.
- ENM_MOUSEEVENTS Sends EN_MSGFILTER notifications for mouse events.
- ENM_OBJECTPOSITIONS Sends EN_OBJECTPOSITIONS notifications.
- ENM_PROTECTED Sends EN_PROTECTED notifications.
- ENM_REQUESTRESIZE Sends EN_REQUESTRESIZE notifications.
- ENM_SCROLL Sends EN_HSCROLL and EN_VSCROLL notifications.
- ENM_SCROLLEVENTS Sends EN_MSGFILTER notifications for mouse wheel events.
- ENM_SELCHANGE Sends EN_SELCHANGE notifications.
- ENM_UPDATE Sends EN_UPDATE notifications.
  rich edit 2.0 and later:
  this flag is ignored and the EN_UPDATE notifications are always sent. However, if Rich Edit 3.0 emulates Rich Edit 1.0, you must use this flag to send EN_UPDATE notifications.
All the above notifications will be sent as WM_NOTIFY message: you have to check the code member of NMHDR structure for the notification message. For example, if you want to register for mouse events (eg. you want to provide a context sensitive popup menu), you must do something like this:
invoke SendMessage,hwndRichEdit,EM_SETEVENTMASK,0,ENM_MOUSEEVENTS ..... ..... WndProc PROC hWnd:DWORD, uMsg:DWORD, wParam:DWORD, lParam:DWORD ..... ..... .ELSEIF uMsg==WM_NOTIFY push esi mov esi,lParam ASSUME esi:ptr NMHDR .IF [esi].code==EN_MSGFILTER ..... [ do something here] ..... .ENDIF pop esi

Example:

The following example is the update of IczEdit in tutorial no. 33. It adds search/replace functionality and accelerator keys to the program. It also processes the mouse events and provides a popup menu on right mouse click.

.386
.model FLAT,STDCALL
OPTION casemap:none

include    \masm32\include\windows.inc
include    \masm32\include\user32.inc
include    \masm32\include\comdlg32.inc
include    \masm32\include\gdi32.inc
include    \masm32\include\kernel32.inc
includelib \masm32\lib\gdi32.lib
includelib \masm32\lib\comdlg32.lib
includelib \masm32\lib\user32.lib
includelib \masm32\lib\kernel32.lib

WinMain PROTO :DWORD,:DWORD,:DWORD,:DWORD

.const
IDR_MAINMENU        equ   101
IDM_OPEN            equ 40001
IDM_SAVE            equ 40002
IDM_CLOSE           equ 40003
IDM_SAVEAS          equ 40004
IDM_EXIT            equ 40005
IDM_COPY            equ 40006
IDM_CUT             equ 40007
IDM_PASTE           equ 40008
IDM_DELETE          equ 40009
IDM_SELECTALL       equ 40010
IDM_OPTION          equ 40011
IDM_UNDO            equ 40012
IDM_REDO            equ 40013
IDD_OPTIONDLG       equ   101
IDC_BACKCOLORBOX    equ  1000
IDC_TEXTCOLORBOX    equ  1001
IDR_MAINACCEL       equ   105
IDD_FINDDLG         equ   102
IDD_GOTODLG         equ   103
IDD_REPLACEDLG      equ   104
IDC_FINDEDIT        equ  1000
IDC_MATCHCASE       equ  1001
IDC_REPLACEEDIT     equ  1001
IDC_WHOLEWORD       equ  1002
IDC_DOWN            equ  1003
IDC_UP              equ  1004
IDC_LINENO          equ  1005
IDM_FIND            equ 40014
IDM_FINDNEXT        equ 40015
IDM_REPLACE         equ 40016
IDM_GOTOLINE        equ 40017
IDM_FINDPREV        equ 40018
RichEditID          equ   300

.data
ClassName       db "IczEditClass",0
AppName         db "IczEdit version 2.0",0
RichEditDLL     db "riched20.dll",0
RichEditClass   db "RichEdit20A",0
NoRichEdit      db "Cannot find riched20.dll",0
ASMFilterString db "ASM Source code (*.asm)",0,"*.asm",0
                db "All Files (*.*)",0,"*.*",0,0
OpenFileFail    db "Cannot open the file",0
WannaSave       db "The data in the control is modified. Want to save it ?",0
FileOpened      dd FALSE
BackgroundColor dd 0FFFFFFh  ; default to white
TextColor       dd 0         ; default to black
hSearch         dd ?         ; handle to the search/replace dialog box
hAccel          dd ?

.data?
hInstance         dd ?
hRichEdit         dd ?
hwndRichEdit      dd ?
FileName          db 256 dup(?)
AlternateFileName db 256 dup(?)
CustomColors      dd 16  dup(?)
FindBuffer        db 256 dup(?)
ReplaceBuffer     db 256 dup(?)
uFlags            dd ?
findtext          FINDTEXTEX <;>

.code
start:
        mov    byte ptr [FindBuffer],0
        mov    byte ptr [ReplaceBuffer],0
        invoke GetModuleHandle, NULL
        mov    hInstance,eax
        invoke LoadLibrary,ADDR RichEditDLL
.IF eax!=0
        mov hRichEdit,eax
        invoke WinMain, hInstance,0,0, SW_SHOWDEFAULT
        invoke FreeLibrary,hRichEdit
.ELSE
        invoke MessageBox,0,ADDR NoRichEdit,ADDR AppName, \
                          MB_OK or MB_ICONERROR
.ENDIF
        invoke ExitProcess,eax
    
WinMain PROC hInst:DWORD,hPrevInst:DWORD,CmdLine:DWORD,CmdShow:DWORD
LOCAL wc:WNDCLASSEX
LOCAL msg:MSG
LOCAL hwnd:DWORD
        mov    wc.cbSize,SIZEOF WNDCLASSEX
        mov    wc.style, CS_HREDRAW or CS_VREDRAW
        mov    wc.lpfnWndProc, OFFSET WndProc
        mov    wc.cbClsExtra,NULL
        mov    wc.cbWndExtra,NULL
        push   hInst
        pop    wc.hInstance
        mov    wc.hbrBackground,COLOR_WINDOW+1
        mov    wc.lpszMenuName,IDR_MAINMENU
        mov    wc.lpszClassName,OFFSET ClassName
        invoke LoadIcon,NULL,IDI_APPLICATION
        mov    wc.hIcon,eax
        mov    wc.hIconSm,eax
        invoke LoadCursor,NULL,IDC_ARROW
        mov    wc.hCursor,eax
        invoke RegisterClassEx, ADDR wc
        invoke CreateWindowEx,NULL,ADDR ClassName,ADDR AppName, \
                              WS_OVERLAPPEDWINDOW,              \
                              CW_USEDEFAULT,CW_USEDEFAULT,      \
                              CW_USEDEFAULT,CW_USEDEFAULT,      \
                              NULL,NULL,hInst,NULL
        mov    hwnd,eax
        invoke ShowWindow, hwnd,SW_SHOWNORMAL
        invoke UpdateWindow, hwnd
        invoke LoadAccelerators,hInstance,IDR_MAINACCEL
        mov    hAccel,eax
.WHILE TRUE
        invoke GetMessage, ADDR msg,0,0,0
.BREAK .IF (!eax)
        invoke IsDialogMessage,hSearch,ADDR msg
.IF eax==FALSE
        invoke TranslateAccelerator,hwnd,hAccel,ADDR msg
.IF eax==0
        invoke TranslateMessage, ADDR msg
        invoke DispatchMessage, ADDR msg
.ENDIF
.ENDIF
.ENDW
        mov   eax,msg.wParam
        ret
WinMain ENDP

StreamInProc PROC hFile:DWORD,pBuffer:DWORD, NumBytes:DWORD,
                  pBytesRead:DWORD
        invoke ReadFile,hFile,pBuffer,NumBytes,pBytesRead,0
        xor    eax,1
        ret
StreamInProc ENDP

StreamOutProc PROC hFile:DWORD,pBuffer:DWORD, NumBytes:DWORD,
                   pBytesWritten:DWORD
        invoke WriteFile,hFile,pBuffer,NumBytes,pBytesWritten,0
        xor    eax,1
        ret
StreamOutProc ENDP

CheckModifyState PROC hWnd:DWORD
        invoke SendMessage,hwndRichEdit,EM_GETMODIFY,0,0
.IF eax!=0
        invoke MessageBox,hWnd,ADDR WannaSave,ADDR AppName,MB_YESNOCANCEL
 .IF eax==IDYES
        invoke SendMessage,hWnd,WM_COMMAND,IDM_SAVE,0
 .ELSEIF eax==IDCANCEL
        mov    eax,FALSE
        ret
 .ENDIF
.ENDIF
        mov    eax,TRUE
        ret
CheckModifyState ENDP

SetColor PROC
LOCAL cfm:CHARFORMAT
        invoke SendMessage,hwndRichEdit,EM_SETBKGNDCOLOR,0,BackgroundColor
        invoke RtlZeroMemory,ADDR cfm,sizeof cfm
        mov    cfm.cbSize,sizeof cfm
        mov    cfm.dwMask,CFM_COLOR
        push   TextColor
        pop    cfm.crTextColor
        invoke SendMessage,hwndRichEdit,EM_SETCHARFORMAT,SCF_ALL,ADDR cfm
        ret
SetColor ENDP

OptionProc PROC hWnd:DWORD, uMsg:DWORD, wParam:DWORD, lParam:DWORD
LOCAL clr:CHOOSECOLOR
.IF uMsg==WM_INITDIALOG
.ELSEIF uMsg==WM_COMMAND
        mov    eax,wParam
        shr    eax,16
.IF ax==BN_CLICKED
        mov    eax,wParam
.IF ax==IDCANCEL
        invoke SendMessage,hWnd,WM_CLOSE,0,0
.ELSEIF ax==IDC_BACKCOLORBOX
        invoke RtlZeroMemory,ADDR clr,sizeof clr
        mov    clr.lStructSize,sizeof clr
        push   hWnd
        pop    clr.hwndOwner
        push   hInstance
        pop    clr.hInstance
        push   BackgroundColor
        pop    clr.rgbResult
        mov    clr.lpCustColors,OFFSET CustomColors
        mov    clr.Flags,CC_ANYCOLOR or CC_RGBINIT
        invoke ChooseColor,ADDR clr
.IF eax!=0
        push   clr.rgbResult
        pop    BackgroundColor
        invoke GetDlgItem,hWnd,IDC_BACKCOLORBOX
        invoke InvalidateRect,eax,0,TRUE
.ENDIF
.ELSEIF ax==IDC_TEXTCOLORBOX
        invoke RtlZeroMemory,ADDR clr,sizeof clr
        mov    clr.lStructSize,sizeof clr
        push   hWnd
        pop    clr.hwndOwner
        push   hInstance
        pop    clr.hInstance
        push   TextColor
        pop    clr.rgbResult
        mov    clr.lpCustColors,OFFSET CustomColors
        mov    clr.Flags,CC_ANYCOLOR or CC_RGBINIT
        invoke ChooseColor,ADDR clr
.IF eax!=0
        push   clr.rgbResult
        pop    TextColor
        invoke GetDlgItem,hWnd,IDC_TEXTCOLORBOX
        invoke InvalidateRect,eax,0,TRUE
.ENDIF
.ELSEIF ax==IDOK
        invoke SendMessage,hwndRichEdit,EM_GETMODIFY,0,0
        push   eax
        invoke SetColor
        pop    eax
        invoke SendMessage,hwndRichEdit,EM_SETMODIFY,eax,0
        invoke EndDialog,hWnd,0
.ENDIF
.ENDIF
.ELSEIF uMsg==WM_CTLCOLORSTATIC
        invoke GetDlgItem,hWnd,IDC_BACKCOLORBOX
.IF eax==lParam
        invoke CreateSolidBrush,BackgroundColor         
        ret
.ELSE
        invoke GetDlgItem,hWnd,IDC_TEXTCOLORBOX
.IF eax==lParam
        invoke CreateSolidBrush,TextColor
        ret
.ENDIF
.ENDIF
        mov    eax,FALSE
        ret
.ELSEIF uMsg==WM_CLOSE
        invoke EndDialog,hWnd,0
.ELSE
        mov    eax,FALSE
        ret
.ENDIF
        mov    eax,TRUE
        ret
OptionProc ENDP

SearchProc PROC hWnd:DWORD, uMsg:DWORD, wParam:DWORD, lParam:DWORD
.IF uMsg==WM_INITDIALOG
        push hWnd
        pop hSearch
        invoke CheckRadioButton,hWnd,IDC_DOWN,IDC_UP,IDC_DOWN
        invoke SendDlgItemMessage,hWnd,IDC_FINDEDIT,WM_SETTEXT,0, \
                                  ADDR FindBuffer
.ELSEIF uMsg==WM_COMMAND
        mov    eax,wParam
        shr    eax,16
.IF ax==BN_CLICKED
        mov    eax,wParam
.IF ax==IDOK
        mov    uFlags,0
        invoke SendMessage,hwndRichEdit,EM_EXGETSEL,0,ADDR findtext.chrg
        invoke GetDlgItemText,hWnd,IDC_FINDEDIT,ADDR FindBuffer, \
                              sizeof FindBuffer
.IF eax!=0
        invoke IsDlgButtonChecked,hWnd,IDC_DOWN
.IF eax==BST_CHECKED
        or     uFlags,FR_DOWN
        mov    eax,findtext.chrg.cpMin
.IF eax!=findtext.chrg.cpMax
        push   findtext.chrg.cpMax
        pop    findtext.chrg.cpMin
.ENDIF
        mov    findtext.chrg.cpMax,-1
.ELSE
        mov    findtext.chrg.cpMax,0
.ENDIF
        invoke IsDlgButtonChecked,hWnd,IDC_MATCHCASE
.IF eax==BST_CHECKED
        or     uFlags,FR_MATCHCASE
.ENDIF
        invoke IsDlgButtonChecked,hWnd,IDC_WHOLEWORD
.IF eax==BST_CHECKED
        or     uFlags,FR_WHOLEWORD
.ENDIF
        mov    findtext.lpstrText,OFFSET FindBuffer
        invoke SendMessage,hwndRichEdit,EM_FINDTEXTEX,uFlags,ADDR findtext
.IF eax!=-1
        invoke SendMessage,hwndRichEdit,EM_EXSETSEL,0,ADDR findtext.chrgText
.ENDIF
.ENDIF
.ELSEIF ax==IDCANCEL
        invoke SendMessage,hWnd,WM_CLOSE,0,0
.ELSE
        mov    eax,FALSE
        ret
.ENDIF
.ENDIF
.ELSEIF uMsg==WM_CLOSE
        mov    hSearch,0
        invoke EndDialog,hWnd,0
.ELSE
        mov    eax,FALSE
        ret
.ENDIF
        mov    eax,TRUE
        ret
SearchProc ENDP

ReplaceProc PROC hWnd:DWORD, uMsg:DWORD, wParam:DWORD, lParam:DWORD
LOCAL settext:SETTEXTEX
.IF uMsg==WM_INITDIALOG
        push   hWnd
        pop    hSearch
        invoke SetDlgItemText,hWnd,IDC_FINDEDIT,ADDR FindBuffer
        invoke SetDlgItemText,hWnd,IDC_REPLACEEDIT,ADDR ReplaceBuffer
.ELSEIF uMsg==WM_COMMAND
        mov    eax,wParam
        shr    eax,16
.IF ax==BN_CLICKED
        mov    eax,wParam
.IF ax==IDCANCEL
        invoke SendMessage,hWnd,WM_CLOSE,0,0
.ELSEIF ax==IDOK
        invoke GetDlgItemText,hWnd,IDC_FINDEDIT,ADDR FindBuffer, \
                              sizeof FindBuffer
        invoke GetDlgItemText,hWnd,IDC_REPLACEEDIT,ADDR ReplaceBuffer, \
                              sizeof ReplaceBuffer
        mov    findtext.chrg.cpMin,0
        mov    findtext.chrg.cpMax,-1
        mov    findtext.lpstrText,OFFSET FindBuffer
        mov    settext.flags,ST_SELECTION
        mov    settext.codepage,CP_ACP
.WHILE TRUE
        invoke SendMessage,hwndRichEdit,EM_FINDTEXTEX,FR_DOWN, \
                           ADDR findtext
.IF eax==-1
.BREAK
.ELSE
        invoke SendMessage,hwndRichEdit,EM_EXSETSEL,0, \
                           ADDR findtext.chrgText
        invoke SendMessage,hwndRichEdit,EM_SETTEXTEX,ADDR settext, \
                           ADDR ReplaceBuffer
.ENDIF
.ENDW
.ENDIF
.ENDIF
.ELSEIF uMsg==WM_CLOSE
        mov    hSearch,0
        invoke EndDialog,hWnd,0
.ELSE
        mov    eax,FALSE
        ret
.ENDIF
        mov    eax,TRUE
        ret
ReplaceProc ENDP

GoToProc PROC hWnd:DWORD, uMsg:DWORD, wParam:DWORD, lParam:DWORD
LOCAL LineNo:DWORD
LOCAL chrg:CHARRANGE
.IF uMsg==WM_INITDIALOG
        push   hWnd
        pop    hSearch
.ELSEIF uMsg==WM_COMMAND
        mov    eax,wParam
        shr    eax,16
.IF ax==BN_CLICKED
        mov    eax,wParam
.IF ax==IDCANCEL
        invoke SendMessage,hWnd,WM_CLOSE,0,0
.ELSEIF ax==IDOK
        invoke GetDlgItemInt,hWnd,IDC_LINENO,NULL,FALSE
        mov    LineNo,eax
        invoke SendMessage,hwndRichEdit,EM_GETLINECOUNT,0,0
.IF eax>LineNo
        invoke SendMessage,hwndRichEdit,EM_LINEINDEX,LineNo,0
        mov    chrg.cpMin,eax
        mov    chrg.cpMax,eax
        invoke SendMessage,hwndRichEdit,EM_EXSETSEL,0,ADDR chrg
        invoke SetFocus,hwndRichEdit
.ENDIF
.ENDIF
.ENDIF
.ELSEIF uMsg==WM_CLOSE
        mov    hSearch,0
        invoke EndDialog,hWnd,0
.ELSE
        mov    eax,FALSE
        ret
.ENDIF
        mov    eax,TRUE
        ret
GoToProc ENDP

PrepareEditMenu PROC hSubMenu:DWORD
LOCAL chrg:CHARRANGE
        invoke SendMessage,hwndRichEdit,EM_CANPASTE,CF_TEXT,0
.IF eax==0                        ; no text in the clipboard
        invoke EnableMenuItem,hSubMenu,IDM_PASTE,MF_GRAYED
.ELSE
        invoke EnableMenuItem,hSubMenu,IDM_PASTE,MF_ENABLED
.ENDIF
        invoke SendMessage,hwndRichEdit,EM_CANUNDO,0,0
.IF eax==0
        invoke EnableMenuItem,hSubMenu,IDM_UNDO,MF_GRAYED
.ELSE
        invoke EnableMenuItem,hSubMenu,IDM_UNDO,MF_ENABLED
.ENDIF
        invoke SendMessage,hwndRichEdit,EM_CANREDO,0,0
.IF eax==0
        invoke EnableMenuItem,hSubMenu,IDM_REDO,MF_GRAYED
.ELSE
        invoke EnableMenuItem,hSubMenu,IDM_REDO,MF_ENABLED
.ENDIF
        invoke SendMessage,hwndRichEdit,EM_EXGETSEL,0,ADDR chrg
        mov    eax,chrg.cpMin
.IF eax==chrg.cpMax     ; no current selection
        invoke EnableMenuItem,hSubMenu,IDM_COPY,MF_GRAYED
        invoke EnableMenuItem,hSubMenu,IDM_CUT,MF_GRAYED
        invoke EnableMenuItem,hSubMenu,IDM_DELETE,MF_GRAYED
.ELSE
        invoke EnableMenuItem,hSubMenu,IDM_COPY,MF_ENABLED
        invoke EnableMenuItem,hSubMenu,IDM_CUT,MF_ENABLED
        invoke EnableMenuItem,hSubMenu,IDM_DELETE,MF_ENABLED
.ENDIF
        ret
PrepareEditMenu ENDP

WndProc PROC hWnd:DWORD, uMsg:DWORD, wParam:DWORD, lParam:DWORD
LOCAL ofn:OPENFILENAME
LOCAL buffer[256]:BYTE
LOCAL editstream:EDITSTREAM
LOCAL hFile:DWORD
LOCAL hPopup:DWORD
LOCAL pt:POINT
LOCAL chrg:CHARRANGE
.IF uMsg==WM_CREATE
        invoke CreateWindowEx,WS_EX_CLIENTEDGE,ADDR RichEditClass,0,   \
                              WS_CHILD or WS_VISIBLE or ES_MULTILINE   \
                           or WS_VSCROLL or WS_HSCROLL or ES_NOHIDESEL,\
                              CW_USEDEFAULT,CW_USEDEFAULT,             \
                              CW_USEDEFAULT,CW_USEDEFAULT,             \
                              hWnd,RichEditID,hInstance,0
        mov    hwndRichEdit,eax
        invoke SendMessage,hwndRichEdit,EM_LIMITTEXT,-1,0
        invoke SetColor
        invoke SendMessage,hwndRichEdit,EM_SETMODIFY,FALSE,0
        invoke SendMessage,hwndRichEdit,EM_SETEVENTMASK,0,ENM_MOUSEEVENTS
        invoke SendMessage,hwndRichEdit,EM_EMPTYUNDOBUFFER,0,0
.ELSEIF uMsg==WM_NOTIFY
        push   esi
        mov    esi,lParam
ASSUME esi:ptr NMHDR
.IF [esi].code==EN_MSGFILTER
ASSUME esi:ptr MSGFILTER
.IF [esi].msg==WM_RBUTTONDOWN
        invoke GetMenu,hWnd
        invoke GetSubMenu,eax,1
        mov    hPopup,eax
        invoke PrepareEditMenu,hPopup
        mov    edx,[esi].lParam
        mov    ecx,edx
        and    edx,0FFFFh
        shr    ecx,16
        mov    pt.x,edx
        mov    pt.y,ecx
        invoke ClientToScreen,hWnd,ADDR pt
        invoke TrackPopupMenu,hPopup,TPM_LEFTALIGN or TPM_BOTTOMALIGN, \
                              pt.x,pt.y,NULL,hWnd,NULL
.ENDIF
.ENDIF
        pop    esi
.ELSEIF uMsg==WM_INITMENUPOPUP
        mov    eax,lParam
.IF ax==0                      ; file menu
.IF FileOpened==TRUE           ; a file is already opened
        invoke EnableMenuItem,wParam,IDM_OPEN,MF_GRAYED
        invoke EnableMenuItem,wParam,IDM_CLOSE,MF_ENABLED
        invoke EnableMenuItem,wParam,IDM_SAVE,MF_ENABLED
        invoke EnableMenuItem,wParam,IDM_SAVEAS,MF_ENABLED
.ELSE
        invoke EnableMenuItem,wParam,IDM_OPEN,MF_ENABLED
        invoke EnableMenuItem,wParam,IDM_CLOSE,MF_GRAYED
        invoke EnableMenuItem,wParam,IDM_SAVE,MF_GRAYED
        invoke EnableMenuItem,wParam,IDM_SAVEAS,MF_GRAYED
.ENDIF
.ELSEIF ax==1                     ; edit menu
        invoke PrepareEditMenu,wParam
.ELSEIF ax==2                     ; search menu bar
.IF FileOpened==TRUE
        invoke EnableMenuItem,wParam,IDM_FIND,MF_ENABLED
        invoke EnableMenuItem,wParam,IDM_FINDNEXT,MF_ENABLED
        invoke EnableMenuItem,wParam,IDM_FINDPREV,MF_ENABLED
        invoke EnableMenuItem,wParam,IDM_REPLACE,MF_ENABLED
        invoke EnableMenuItem,wParam,IDM_GOTOLINE,MF_ENABLED
.ELSE
        invoke EnableMenuItem,wParam,IDM_FIND,MF_GRAYED
        invoke EnableMenuItem,wParam,IDM_FINDNEXT,MF_GRAYED
        invoke EnableMenuItem,wParam,IDM_FINDPREV,MF_GRAYED
        invoke EnableMenuItem,wParam,IDM_REPLACE,MF_GRAYED
        invoke EnableMenuItem,wParam,IDM_GOTOLINE,MF_GRAYED
.ENDIF
.ENDIF
.ELSEIF uMsg==WM_COMMAND
.IF lParam==0                     ; menu commands
        mov    eax,wParam
.IF ax==IDM_OPEN
        invoke RtlZeroMemory,ADDR ofn,sizeof ofn
        mov    ofn.lStructSize,sizeof ofn
        push   hWnd
        pop    ofn.hwndOwner
        push   hInstance
        pop    ofn.hInstance
        mov    ofn.lpstrFilter,OFFSET ASMFilterString
        mov    ofn.lpstrFile,OFFSET FileName
        mov    byte ptr [FileName],0
        mov    ofn.nMaxFile,sizeof FileName
        mov    ofn.Flags,OFN_FILEMUSTEXIST or OFN_HIDEREADONLY or OFN_PATHMUSTEXIST
        invoke GetOpenFileName,ADDR ofn
.IF eax!=0
        invoke CreateFile,ADDR FileName,GENERIC_READ,FILE_SHARE_READ, \
                          NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,0
.IF eax!=INVALID_HANDLE_VALUE
        mov    hFile,eax
;============================================================
; stream the text into the richedit control
;============================================================
        mov    editstream.dwCookie,eax
        mov    editstream.pfnCallback,OFFSET StreamInProc
        invoke SendMessage,hwndRichEdit,EM_STREAMIN,SF_TEXT, \
                           ADDR editstream
;============================================================
; Initialize the modify state to false
;============================================================
        invoke SendMessage,hwndRichEdit,EM_SETMODIFY,FALSE,0
        invoke CloseHandle,hFile
        mov    FileOpened,TRUE
.ELSE
        invoke MessageBox,hWnd,ADDR OpenFileFail,ADDR AppName, \
                          MB_OK or MB_ICONERROR
.ENDIF
.ENDIF
.ELSEIF ax==IDM_CLOSE
        invoke CheckModifyState,hWnd
.IF eax==TRUE
        invoke SetWindowText,hwndRichEdit,0
        mov    FileOpened,FALSE
.ENDIF
.ELSEIF ax==IDM_SAVE
        invoke CreateFile,ADDR FileName,GENERIC_WRITE,FILE_SHARE_READ, \
                          NULL,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,0
.IF eax!=INVALID_HANDLE_VALUE
@@:             
        mov hFile,eax
;============================================================
; stream the text to the file
;============================================================
        mov    editstream.dwCookie,eax
        mov    editstream.pfnCallback,OFFSET StreamOutProc
        invoke SendMessage,hwndRichEdit,EM_STREAMOUT,SF_TEXT, \
                           ADDR editstream
;============================================================
; Initialize the modify state to false
;============================================================
        invoke SendMessage,hwndRichEdit,EM_SETMODIFY,FALSE,0
        invoke CloseHandle,hFile
.ELSE
        invoke MessageBox,hWnd,ADDR OpenFileFail,ADDR AppName, \
                          MB_OK or MB_ICONERROR
.ENDIF
.ELSEIF ax==IDM_COPY
        invoke SendMessage,hwndRichEdit,WM_COPY,0,0
.ELSEIF ax==IDM_CUT
        invoke SendMessage,hwndRichEdit,WM_CUT,0,0
.ELSEIF ax==IDM_PASTE
        invoke SendMessage,hwndRichEdit,WM_PASTE,0,0
.ELSEIF ax==IDM_DELETE
        invoke SendMessage,hwndRichEdit,EM_REPLACESEL,TRUE,0
.ELSEIF ax==IDM_SELECTALL
        mov    chrg.cpMin,0
        mov    chrg.cpMax,-1
        invoke SendMessage,hwndRichEdit,EM_EXSETSEL,0,ADDR chrg
.ELSEIF ax==IDM_UNDO
        invoke SendMessage,hwndRichEdit,EM_UNDO,0,0
.ELSEIF ax==IDM_REDO
        invoke SendMessage,hwndRichEdit,EM_REDO,0,0
.ELSEIF ax==IDM_OPTION
        invoke DialogBoxParam,hInstance,IDD_OPTIONDLG,hWnd, \
                              ADDR OptionProc,0
.ELSEIF ax==IDM_SAVEAS
        invoke RtlZeroMemory,ADDR ofn,sizeof ofn
        mov    ofn.lStructSize,sizeof ofn
        push   hWnd
        pop    ofn.hwndOwner
        push   hInstance
        pop    ofn.hInstance
        mov    ofn.lpstrFilter,OFFSET ASMFilterString
        mov    ofn.lpstrFile,OFFSET AlternateFileName
        mov    byte ptr [AlternateFileName],0
        mov    ofn.nMaxFile,sizeof AlternateFileName
        mov    ofn.Flags,OFN_FILEMUSTEXIST or OFN_HIDEREADONLY \
                      or OFN_PATHMUSTEXIST
        invoke GetSaveFileName,ADDR ofn
.IF eax!=0
        invoke CreateFile,ADDR AlternateFileName,GENERIC_WRITE, \
                          FILE_SHARE_READ,NULL,CREATE_ALWAYS,   \
                          FILE_ATTRIBUTE_NORMAL,0
.IF eax!=INVALID_HANDLE_VALUE
        jmp    @B
.ENDIF
.ENDIF
.ELSEIF ax==IDM_FIND
.IF hSearch==0
        invoke CreateDialogParam,hInstance,IDD_FINDDLG,hWnd, \
                                 ADDR SearchProc,0
.ENDIF
.ELSEIF ax==IDM_REPLACE
.IF hSearch==0
        invoke CreateDialogParam,hInstance,IDD_REPLACEDLG,hWnd, \
                                 ADDR ReplaceProc,0
.ENDIF
.ELSEIF ax==IDM_GOTOLINE
.IF hSearch==0
        invoke CreateDialogParam,hInstance,IDD_GOTODLG,hWnd, \
                                 ADDR GoToProc,0
.ENDIF
.ELSEIF ax==IDM_FINDNEXT
        invoke lstrlen,ADDR FindBuffer
.IF eax!=0
        invoke SendMessage,hwndRichEdit,EM_EXGETSEL,0,ADDR findtext.chrg
        mov    eax,findtext.chrg.cpMin
.IF eax!=findtext.chrg.cpMax
        push   findtext.chrg.cpMax
        pop    findtext.chrg.cpMin
.ENDIF
        mov    findtext.chrg.cpMax,-1
        mov    findtext.lpstrText,OFFSET FindBuffer
        invoke SendMessage,hwndRichEdit,EM_FINDTEXTEX,FR_DOWN, \
                           ADDR findtext
.IF eax!=-1
        invoke SendMessage,hwndRichEdit,EM_EXSETSEL,0, \
                           ADDR findtext.chrgText
.ENDIF
.ENDIF
.ELSEIF ax==IDM_FINDPREV
        invoke lstrlen,ADDR FindBuffer
.IF eax!=0
        invoke SendMessage,hwndRichEdit,EM_EXGETSEL,0,ADDR findtext.chrg
        mov    findtext.chrg.cpMax,0
        mov    findtext.lpstrText,OFFSET FindBuffer
        invoke SendMessage,hwndRichEdit,EM_FINDTEXTEX,0,ADDR findtext
.IF eax!=-1
        invoke SendMessage,hwndRichEdit,EM_EXSETSEL,0, \
                           ADDR findtext.chrgText
.ENDIF
.ENDIF
.ELSEIF ax==IDM_EXIT
        invoke SendMessage,hWnd,WM_CLOSE,0,0
.ENDIF
.ENDIF
.ELSEIF uMsg==WM_CLOSE
        invoke CheckModifyState,hWnd
.IF eax==TRUE
        invoke DestroyWindow,hWnd
.ENDIF
.ELSEIF uMsg==WM_SIZE
        mov    eax,lParam
        mov    edx,eax
        and    eax,0FFFFh
        shr    edx,16
        invoke MoveWindow,hwndRichEdit,0,0,eax,edx,TRUE     
.ELSEIF uMsg==WM_DESTROY
        invoke PostQuitMessage,NULL
.ELSE
        invoke DefWindowProc,hWnd,uMsg,wParam,lParam        
        ret
.ENDIF
        xor    eax,eax
        ret
WndProc ENDP

END start

Analysis

The search-for-text capability is implemented with EM_FINDTEXTEX. When the user clicks on Find menuitem, IDM_FIND message is sent and the Find dialog box is displayed.

        invoke GetDlgItemText,hWnd,IDC_FINDEDIT,ADDR FindBuffer, \
                              sizeof FindBuffer
.IF eax!=0

When the user types the text to search for and then press OK button, we get the text to be searched for into FindBuffer.

        mov uFlags,0
        invoke SendMessage,hwndRichEdit,EM_EXGETSEL,0,ADDR findtext.chrg

If the text string is not null, we continue to initialize uFlags variable to 0.This variable is used to store the search flags used withEM_FINDTEXTEX. After that, we obtain the current selection with EM_EXGETSEL because we need to know the starting point of the search operation.

        invoke IsDlgButtonChecked,hWnd,IDC_DOWN
.IF eax==BST_CHECKED
        or     uFlags,FR_DOWN
        mov    eax,findtext.chrg.cpMin
.IF eax!=findtext.chrg.cpMax
        push   findtext.chrg.cpMax
        pop    findtext.chrg.cpMin
.ENDIF
        mov    findtext.chrg.cpMax,-1
.ELSE
        mov    findtext.chrg.cpMax,0
.ENDIF

The next part is a little tricky. We check the direction radio button to ascertain which direction the search should go. If the downward search is indicated, we set FR_DOWN flag to uFlags. After that, we check whether a selection is currently in effect by comparing the values of cpMin and cpMax. If both values are not equal, it means there is a current selection and we must continue the search from the END of that selection to the END of text in the control. Thus we need to replace the value of cpMax with that of cpMin and change the value of cpMax to -1 (0FFFFFFFFh). If there is no current selection, the range to search is from the current caret position to the END of text.

If the user chooses to search upward, we use the range from the start of the selection to the beginning of the text in the control. That's why we only modify the value of cpMax to 0. In the case of upward search, cpMin contains the character index of the last character in the search range and cpMax the character index of the first char in the search range. It's the inverse of the downward search.

        invoke IsDlgButtonChecked,hWnd,IDC_MATCHCASE
.IF eax==BST_CHECKED
        or     uFlags,FR_MATCHCASE
.ENDIF
        invoke IsDlgButtonChecked,hWnd,IDC_WHOLEWORD
.IF eax==BST_CHECKED
        or     uFlags,FR_WHOLEWORD
.ENDIF
        mov    findtext.lpstrText,OFFSET FindBuffer

We continue to check the checkboxes for the search flags, ie, FR_MATCHCASE and FR_WHOLEWORD. Lastly, we put the OFFSET of the text to search for in lpstrText member.

        invoke SendMessage,hwndRichEdit,EM_FINDTEXTEX,uFlags, \
                           ADDR findtext
.IF eax!=-1
        invoke SendMessage,hwndRichEdit,EM_EXSETSEL,0,        \
                           ADDR findtext.chrgText
.ENDIF
.ENDIF

We are now ready to issue EM_FINDTEXTEX. After that, we examine the search result returned by SendMessage. If the return value is -1, no match is found in the search range. Otherwise, chrgText member of FINDTEXTEX structure is filled with the character indices of the matching text. We thus proceed to select it with EM_EXSETSEL

The replace operation is done in much the same manner.

        invoke GetDlgItemText,hWnd,IDC_FINDEDIT,ADDR FindBuffer,       \
                              sizeof FindBuffer
        invoke GetDlgItemText,hWnd,IDC_REPLACEEDIT,ADDR ReplaceBuffer, \
                              sizeof ReplaceBuffer

We retrieve the text to search for and the text used to replace.

        mov    findtext.chrg.cpMin,0
        mov    findtext.chrg.cpMax,-1
        mov    findtext.lpstrText,OFFSET FindBuffer

To make it easy, the replace operation affects all the text in the control. Thus the starting index is 0 and the ending index is -1.

        mov settext.flags,ST_SELECTION
        mov    settext.codepage,CP_ACP

We initialize SETTEXTEX structure to indicate that we want to replace the current selection and use the default system code page.

.WHILE TRUE
        invoke SendMessage,hwndRichEdit,EM_FINDTEXTEX,FR_DOWN, \
                           ADDR findtext
.IF eax==-1
.BREAK
.ELSE
        invoke SendMessage,hwndRichEdit,EM_EXSETSEL,0, \
                           ADDR findtext.chrgText
        invoke SendMessage,hwndRichEdit,EM_SETTEXTEX,ADDR settext, \
                           ADDR ReplaceBuffer    
.ENDIF
.ENDW

We enter an infinite loop, searching for the matching text. If one is found, we select it with EM_EXSETSEL and replace it with EM_SETTEXTEX. When no more match is found, we exit the loop.

find next and find prev. features use EM_FINDTEXTEX message in the similar manner to the find operation.

We will examine the Go to Line feature next. When the user clicks Go To Line menuitem, we display a dialog box below:

When the user types a line number and presses Ok button, we begin the operation.

        invoke GetDlgItemInt,hWnd,IDC_LINENO,NULL,FALSE
        mov    LineNo,eax

Obtain the line number from the edit control

        invoke SendMessage,hwndRichEdit,EM_GETLINECOUNT,0,0
 .IF eax>LineNo

Obtain the number of lines in the control. Check whether the user specifies the line number that is out of the range.

invoke SendMessage,hwndRichEdit,EM_LINEINDEX,LineNo,0

If the line number is valid, we want to move the caret to the first character of that line. So we send EM_LINEINDEX message to the richedit control. This message returns the character index of the first character in the specified line. We send the line number in wParam and in return, we has the character index.

invoke SendMessage,hwndRichEdit,EM_SETSEL,eax,eax

To set the current selection, this time we use EM_SETSEL because the character indices are not already in a CHARRANGE structure thus it saves us two instructions (to put those indices into a CHARRANGE structure).

        invoke SetFocus,hwndRichEdit
.ENDIF

The caret will not be displayed unless the richedit control has the focus. So we call SetFocus on it.

Tutorial 32: Multiple Document Interface (MDI)

Overview

Tutorial 34: RichEdit Control: More Text Operations