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' ------------------------------------------------------------------------ ' Visual Basic for MS-DOS Help Toolkit ' ' The Help Toolkit (HELP.BAS, HELPF.FRM, and HELPUTIL.FRM) ' makes it easy to add a hypertext Help system to your ' applications. ' ' To use the Help Toolkit in your programs, include ' HELP.BAS, HELPF.FRM, and HELPUTIL.FRM in your program or ' use the supplied library (HELP.LIB, HELPA.LIB - AltMath ' version) and Quick library (HELP.QLB) and call the ' appropriate routines to load and display your help topics. ' Forms and code modules that call Help routines ' must include HELP.BI ('$INCLUDE: 'HELP.BI'). ' ' Help files can be written in any ASCII text editor or ' in Visual Basic itself. Refer to the sample Help file ' HELPDEMO.TXT as an example of the Help file format. ' HELPDEMO.TXT also contains full information on creating ' Help files and using the Help Toolkit to display and ' navigate them. ' ' The Help ToolKit consists of the following routines: ' HelpRegister - initializes the Help system and loads Help file ' HelpShowTopic - displays specified Help topic ' HelpClose - closes Help file ' HelpSetOptions - sets Help display options ' HelpSearch - invokes Help Search dialog to enable topic search ' Detailed descriptions of these procedures are contained ' in the comment headers above each. ' ' Copyright (C) 1982-1992 Microsoft Corporation ' ' You have a royalty-free right to use, modify, reproduce ' and distribute the sample applications and toolkits provided with ' Visual Basic for MS-DOS (and/or any modified version) ' in any way you find useful, provided that you agree that ' Microsoft has no warranty, obligations or liability for ' any of the sample applications or toolkits. ' ------------------------------------------------------------------------ ' Include file containing procedure declarations. '$INCLUDE: 'HELP.BI' '$FORM frmHelpUtils ' Form for Search, History, and Change dialogs '$FORM frmHelpMain ' Help window TYPE IndexType ' Used to index Help topics StartFilePtr AS LONG ' Position within the topic's file NumLines AS INTEGER ' Number of lines in the Help topic END TYPE TYPE PointType X AS INTEGER ' Horizontal location Y AS INTEGER ' Vertical location END TYPE ' Variables common to HELP.BAS, HELPF.FRM, and HELPUTIL.FRM. COMMON SHARED /HelpLib/ DialogBackcolor AS INTEGER ' Background color for Help dialog boxes (Search, Copy, History) COMMON SHARED /HelpLib/ DialogForecolor AS INTEGER ' Foreground color for Help dialog boxes (Search, Copy, History) ' Variables common to HELP.BAS and HELPF.FRM. COMMON SHARED /HelpLib/ Topic() AS STRING ' Lines of the current Help topic COMMON SHARED /HelpLib/ LeftChar AS INTEGER ' Leftmost character of the Help topic given the horizonal scroll position COMMON SHARED /HelpLib/ StartLine AS INTEGER ' Top line of the Help topic given the vertical scroll position COMMON SHARED /HelpLib/ MaxLineLen AS INTEGER ' Longest line of the Help topic COMMON SHARED /HelpLib/ HelpIndexPtr() AS IndexType ' Table that stores data about each Help topic COMMON SHARED /HelpLib/ HelpIndexTopics() AS STRING ' Array of Help topic names. Used with the HelpIndexPtr table. COMMON SHARED /HelpLib/ HelpFileNum AS INTEGER ' Logical file number assigned to the Help file by HelpRegister COMMON SHARED /HelpLib/ HelpTopicStack() AS STRING ' Array of the last 20 Help topics shown COMMON SHARED /HelpLib/ HelpTopicStackPtr AS INTEGER ' Number of topics in the HelpTopicStack COMMON SHARED /HelpLib/ TopicFound AS STRING ' The Help topic being shown COMMON SHARED /HelpLib/ MaxHistoryStack AS INTEGER ' Maximum allowed size of the HelpTopicStack. HelpRegister sets to 20. COMMON SHARED /HelpLib/ UnloadOnClose AS INTEGER ' Flag that determines if closing the Help form terminates the Help system. COMMON SHARED /HelpLib/ KillHelp AS INTEGER ' Flag that HelpClose sets to terminate the Help form COMMON SHARED /HelpLib/ CursorPos AS PointType ' Position of the currently selected Help link within a topic COMMON SHARED /HelpLib/ ButtonBarHeight AS INTEGER ' Number of lines to reserve at the top of the form for the button bar. 0 or 3. COMMON SHARED /HelpLib/ CloseOnEscape AS INTEGER ' If TRUE, pressing ESC will close the Help window DEFINT A-Z CONST FALSE = 0 CONST TRUE = NOT FALSE CONST TabSpaces = 4 ' Number of spaces that a TAB represents DIM SHARED SelectedTopicColor AS INTEGER ' The foreground color of Help links DIM SHARED SpaceString AS STRING ' A string of blank spaces used by the HelpPrintText procedure DIM SHARED HelpFileName AS STRING ' Help file name. '---------------------------------------------------- ' Sample usage of the Help Toolkit. This code is ' only executed if HELP.BAS is the start-up file. ' Parameter information for each Help procedure is ' contained in the header comments for the procedure. '---------------------------------------------------- ' Set the title bar background color to magenta (5), ' the screen background color to blue (1), and the ' access key color to red (4). screen.controlpanel(16) = 5 screen.controlpanel(5) = 1 screen.controlpanel(0) = 4 ' Initialize the Help system and load specified Help file. ' HelpLoaded% returns whether or not the Help file was ' loaded successfully. HelpRegister "HELPDEMO.TXT", HelpLoaded% ' HelpLoaded% will be FALSE if HelpRegister fails. IF HelpLoaded% THEN ' Set Help color and button display options. ' Calls to this routine are optional as Help will ' use its defaults if this call is ommitted. HelpSetOptions 3, 0, 7, 0, 7, 11, 2 ' Show the table of contents topic for the Help file. ' Help will remain visible until window is closed ' by the user. Help topics can be changed by the user ' once the Help window is made visible with the first ' topic displayed. HelpShowTopic "Contents" END IF ' Help close and unload routine. ' ' Closes help file and unloads help form. ' This routine should be called when the ' parent application terminates. If the parent ' routine has no END statement (e.g. it stops when ' the user closes the last form), the last Form_Unload ' must call this procedure. Otherwise, the application ' will not end because frmHelpMain will still be loaded. ' SUB HelpClose () KillHelp = TRUE UNLOAD frmHelpMain END SUB ' Internal routine that returns the greater of two integers. ' FUNCTION HelpMax (int1 AS INTEGER, int2 AS INTEGER) AS INTEGER IF int1 > int2 THEN HelpMax = int1 ELSE HelpMax = int2 END IF END FUNCTION ' Internal routine that returns the lower of two integers. ' FUNCTION HelpMin (int1 AS INTEGER, int2 AS INTEGER) AS INTEGER IF int1 > int2 THEN HelpMin = int2 ELSE HelpMin = int1 END IF END FUNCTION ' Help topic print routine. ' ' Internal routine that prints Help topic text. ' Called when a topic is first shown and when ' the form is scrolled. ' ' Parameters: ' TopLine - The first element (line) of the topic ' array to be displayed. ' LeftPos - The first character of each topic line ' to be displayed. ' SUB HelpPrintText (TopLine AS INTEGER, LeftPos AS INTEGER) MaxLines = UBOUND(Topic) ' The number of lines in the Help topic. IF TopLine > MaxLines THEN EXIT SUB LastPrintedLine = TopLine + frmHelpMain.pctBackground.ScaleHeight ' The last line of the Help topic that will be printed. IF LastPrintedLine > MaxLines THEN ' Ensures that the routine does not attempt to print more lines than the topic size LastPrintedLine = MaxLines END IF blanklines = frmHelpMain.pctBackground.ScaleHeight - (LastPrintedLine - TopLine - ButtonBarHeight) ' Number of blank lines on the form. FormWidth = frmHelpMain.pctBackground.ScaleWidth ' Local variable copy of the form width. Used to minimize property access. frmHelpMain.pctBackground.CurrentY = 0 ' Start printing at the top of the picture control ' Print the necessary topic lines. FOR i = TopLine TO LastPrintedLine frmHelpMain.pctBackground.PRINT MID$(Topic(i) + SpaceString, LeftPos, FormWidth) NEXT i ' Print as many blank lines as required. DO WHILE blanklines > 0 blanklines = blanklines - 1 frmHelpMain.pctBackground.PRINT SpaceString LOOP ' Set the common variables StartLine and LeftChar based ' on parameters passed to this routine. StartLine = TopLine LeftChar = LeftPos ' Do a quick check to see if there is a highlighted ' link. CursorPos.Y will be 0 if the users has not ' pressed TAB or Shift-TAB in this topic. Skips a lot ' of code if there is no selected Help link. ' IF CursorPos.Y > 0 THEN DIM PrintTopicFound AS STRING ' String containing the selected Help link ' Is the selected link within the currently visible ' vertical region of the form? IF CursorPos.Y >= StartLine AND CursorPos.Y <= LastPrintedLine THEN ' Yes. ' Now see if it's in the visible horizontal ' region IF CursorPos.X >= LeftPos AND CursorPos.X <= LeftPos + FormWidth THEN ' The entire link text will fit horizontally frmHelpMain.pctBackground.CurrentX = CursorPos.X - LeftPos PrintTopicFound = TopicFound ELSEIF CursorPos.X + LEN(TopicFound) >= LeftPos AND CursorPos.X <= LeftPos + FormWidth THEN ' Part of the link text will fit horizontally frmHelpMain.pctBackground.CurrentX = 0 PrintTopicFound = MID$(TopicFound, LeftChar - CursorPos.X + 1) END IF ' Print the link text in the SelectedTopicColor ' if it is in the visible region. IF PrintTopicFound <> "" THEN frmHelpMain.pctBackground.CurrentY = CursorPos.Y - StartLine RealColor = frmHelpMain.pctBackground.Forecolor frmHelpMain.pctBackground.Forecolor = SelectedTopicColor frmHelpMain.pctBackground.PRINT PrintTopicFound frmHelpMain.pctBackground.Forecolor = RealColor END IF END IF END IF ' Set the scroll bar values. frmHelpMain.vscHelp.Value = StartLine frmHelpMain.hscHelp.Value = LeftChar ' Make sure the Help form is visible. frmHelpMain.SHOW END SUB ' Help initialization routine. ' ' Initializes the Help Toolkit by scanning through ' the specified Help file to create a table of ' all Help topics. This routine MUST be ' called BEFORE using any other Help Toolkit ' routines. ' ' Parameters: ' HelpFile$ - The MS-DOS file name of the Help file. ' Must include file extensions (e.g. HELPDEMO.TXT). ' Success% - Signals whether Help initialization was successful. ' ' Topics must be defined in the Help file as follows ' for HelpRegister to recognize them. See HELPDEMO.TXT ' for a complete example. ' .TOPIC: ' topic_name ' Topic Text Goes Here.... ' SUB HelpRegister (HelpFile$, Success%) Success% = FALSE ' Default option settings. HelpSetOptions can override. ButtonBarHeight = 3 SelectedTopicColor = screen.controlpanel(0) DialogBackcolor = 7 DialogForecolor = 0 ' Assume there are 50 help topics in the file. MaxTopics = 50 REDIM HelpIndexPtr(MaxTopics) AS IndexType REDIM HelpIndexTopics(MaxTopics) AS STRING HelpFileNum = FREEFILE ON LOCAL ERROR GOTO HelpFileNotFound OPEN HelpFile$ FOR INPUT AS HelpFileNum ON LOCAL ERROR GOTO 0 DO WHILE NOT EOF(HelpFileNum) LINE INPUT #HelpFileNum, temp$ IF RTRIM$(temp$) = ".TOPIC:" THEN ' Now that it hit a .TOPIC:, it knows how ' many lines were in the previous ' topic so goes back and fills in ' the # of lines for the PREVIOUS ' topic. Will fill element 0, by the way. HelpIndexPtr(NumTopics).NumLines = LinesRead ' Now clear LinesRead for this new ' topic and increment the number of topics. LinesRead = 0 NumTopics = NumTopics + 1 ' Are the arrays large enough given the number ' Help topics? IF NumTopics > MaxTopics THEN ' No. More topics than current array ' allocation so grow the arrays by another ' 50 elements. MaxTopics = MaxTopics + 50 ON LOCAL ERROR GOTO HelpOutOfMemory REDIM PRESERVE HelpIndexPtr(MaxTopics) AS IndexType REDIM PRESERVE HelpIndexTopics(MaxTopics) AS STRING ON LOCAL ERROR GOTO 0 END IF ' The next line in the file must be the topic ' name. LINE INPUT #HelpFileNum, HelpIndexTopics(NumTopics) ' Remember where the Help topic actually ' starts so HelpShowTopic can jump to it ' immediately when a jump is requested. HelpIndexPtr(NumTopics).StartFilePtr = SEEK(HelpFileNum) ELSE ' Line was not a Topic marker or the first line ' after a topic marker. Increment the number ' of lines in this topic. LinesRead = LinesRead + 1 END IF LOOP ' Abort the registration process if no Help topics ' were found. IF NumTopics = 0 THEN MSGBOX HelpFile$ + " is not a valid Help file.", 0, "Help" HelpFileNum = 0 EXIT SUB END IF ' Completes the table entries for the last topic HelpIndexPtr(NumTopics).NumLines = LinesRead ' Shrink the arrays to the exact size required ON LOCAL ERROR GOTO HelpOutOfMemory REDIM PRESERVE HelpIndexPtr(NumTopics) AS IndexType REDIM PRESERVE HelpIndexTopics(NumTopics) AS STRING ON LOCAL ERROR GOTO 0 ' Initialize variables HelpTopicStackPtr = 0 frmHelpMain.cmdButtonBar(0).Enabled = TRUE ' Enable the Contents button frmHelpMain.cmdButtonBar(1).Enabled = TRUE ' Enable the Search button MaxHistoryStack = 20 ON LOCAL ERROR GOTO HelpOutOfMemory REDIM HelpTopicStack(MaxHistoryStack) AS STRING ON LOCAL ERROR GOTO 0 SpaceString = STRING$(screen.width, 32) IF HelpFileNum > 0 THEN Success% = TRUE ' Store a fully qualified HelpFile name ' in case the Help file needs to be ' re-registered later. The full path ' name is stored so the Help Toolkit can ' always find the file even if an application ' causes CURDIR$ to change. ' IF INSTR(HelpFile$, "\") = 0 THEN ' No slash in the file name so local ' file name was provided. Add path ' info. IF RIGHT$(CURDIR$, 1) = "\" THEN HelpFileName = CURDIR$ + HelpFile$ ELSE HelpFileName = CURDIR$ + "\" + HelpFile$ END IF ELSE ' Path info was already provided HelpFileName = HelpFile$ END IF END IF EXIT SUB ' Local error handlers HelpOutOfMemory: MSGBOX "Insufficient memory to display Help.", 0, "Help" HelpClose EXIT SUB HelpFileNotFound: ' Construct a fully qualified file name IF RIGHT$(CURDIR$, 1) = "\" THEN UseFile$ = CURDIR$ + HelpFile$ ELSE UseFile$ = CURDIR$ + "\" + HelpFile$ END IF MSGBOX "Help file " + UseFile$ + " not found.", 0, "Help" HelpClose EXIT SUB END SUB ' Help search routine. ' ' Displays Help Search dialog and searchs for ' selected Help topic. ' SUB HelpSearch () ' Confirm that a Help file is open. IF HelpFileNum = 0 THEN ' No open Help file. HelpFileName will ' be null if HelpRegister was never successful ' but will have a valid file name if a Help ' file was registered correctly but an error ' such as Insufficient Memory to Display Help ' caused Help to close. Also occurs if ' HelpSearch is called after the Help ' form is unloaded (e.g. if HelpSetOptions ' set UnloadOnClose to TRUE). IF HelpFileName = "" THEN MSGBOX "Help Search can only be used after registering a valid Help file.", 0, "Help" EXIT SUB ELSE ' Register the Help file again. HelpRegister HelpFileName, HelpLoaded IF HelpLoaded = FALSE THEN MSGBOX "Help Search can only be used after registering a valid Help file.", 0, "Help" EXIT SUB END IF END IF END IF ' Fill the search list box with all the Help ' topics. LstSearch.Sorted = TRUE so the topics will ' be listed alphabetically. FOR i = 1 TO UBOUND(HelpIndexTopics) frmHelpUtils.lstSearch.ADDITEM HelpIndexTopics(i) NEXT i ' Set the list index to the top. frmHelpUtils.lstSearch.ListIndex = 0 ' Show the Search form modally. frmHelpUtils.SHOW 1 ' The search form's tag property will be set ' to the topic the user selected or null if Cancel ' was selected. RequestedTopic$ = frmHelpUtils.Tag UNLOAD frmHelpUtils ' pctBackground must always have the focus so keys can ' be trapped. IF frmHelpMain.visible THEN frmHelpMain.pctBackground.SETFOCUS ' Show the selected topic. IF RequestedTopic$ <> "" THEN HelpShowTopic RequestedTopic$ END IF END SUB ' Help option setting routine. ' ' Sets colors and shows/hides buttons on the ' Help window's button bar. This routine is ' optional as default settings are provided. ' ' Parameters: ' BColor - Sets help window background color (frmHelpMain.pctBackground.BackColor) ' FColor - Sets help window foreground color (frmHelpMain.pctBackground.ForeColor) ' DBColor - Sets the background color for Help dialogs (Search, Copy, History). ' DFColor - Sets the foreground color for Help dialogs (Search, Copy, History). ' ButtonColor - Sets the background color for the five ' help window button bar. Set SCREEN.CONTROLPANEL(4) ' to change button foreground color. ' SelectColor - Sets the color of the link markers. ' Flags - Bit flags set the VISIBLE status ' of the five command buttons and ' enable other Help Toolit options. ' Add the values below to show buttons ' and enable options. ' ' Function Value Default ' --------------------- ----- ------- ' ESC closes Help 1 0 (Escape key does not close help window) ' UNLOAD Help at Form close 2 0 (Help form in made invisible, not unloaded when form is closed) ' No Contents Button 4 0 (Contents button is visible) ' No Search Button 8 0 (Search button is visible) ' No Back Button 16 0 (Back button is visible) ' No History Button 32 0 (History button is visible) ' No Copy Button 64 0 (Copy button is visible) ' ' For example, Flags = 65 allows ESC to ' close Help and hides the Copy button. ' Space for the button bar is only reserved ' at the top frmHelpMain if at least one button is visible. ' SUB HelpSetOptions (bcolor AS INTEGER, fcolor AS INTEGER, dbColor AS INTEGER, dfColor AS INTEGER, buttoncolor AS INTEGER, SelectColor AS INTEGER, Flags AS INTEGER) ' Trap to ensure HelpRegister has already been called. IF HelpFileNum = 0 THEN MSGBOX "You must call the HelpRegister procedure before calling HelpSetOptions. Proposed settings ignored.", 0, "Help" EXIT SUB END IF ' Confirm that the proposed color settings are valid. ' If so, set the appropriate properties or variables. IF bcolor >= 0 AND bcolor <= 15 THEN frmHelpMain.pctBackground.Backcolor = bcolor IF fcolor >= 0 AND fcolor <= 15 THEN frmHelpMain.pctBackground.Forecolor = fcolor IF SelectColor >= 0 AND SelectColor <= 15 THEN SelectedTopicColor = SelectColor IF dbColor >= 0 AND dbColor <= 15 THEN DialogBackcolor = dbColor IF dfColor >= 0 AND dfColor <= 15 THEN DialogForecolor = dfColor IF buttoncolor >= 0 AND buttoncolor <= 15 THEN frmHelpMain.Backcolor = buttoncolor FOR i = 0 TO 4 frmHelpMain.cmdButtonBar(i).Backcolor = buttoncolor NEXT i END IF ' Hide or show buttons as requested FOR i = 0 TO 4 IF (Flags AND 2 ^ (i + 3)) = FALSE THEN frmHelpMain.cmdButtonBar(i).Left = 13 * NumButtons frmHelpMain.cmdButtonBar(i).visible = TRUE NumButtons = NumButtons + 1 ELSE frmHelpMain.cmdButtonBar(i).visible = FALSE END IF NEXT i ' Allow space for the button bar if at least one button ' is shown. IF NumButtons = 0 THEN ButtonBarHeight = 0 ELSE ButtonBarHeight = 3 END IF CloseOnEscape = Flags AND 1 UnloadOnClose = Flags AND 2 END SUB ' Help topic display routine. ' ' Displays the requested topic on the Help form. ' ' Parameter: ' ProvidedTopic$ - The name of the topic that should be shown. ' SUB HelpShowTopic (ProvidedTopic$) ' Confirm that a Help file has been registered and ' that non-null topic has been provided. IF ProvidedTopic$ = "" THEN MSGBOX "A Help topic must be supplied", 0, "Help" EXIT SUB END IF ' Confirm that a Help file is open. IF HelpFileNum = 0 THEN ' No open Help file. HelpFileName will ' be null if HelpRegister was never successful ' but will have a valid file name if a Help ' file was registered correctly but an error ' such as Insufficient Memory to Display Help ' caused Help to close. Also occurs if ' HelpShowTopic is called after the Help ' form is unloaded (e.g. if HelpSetOptions ' set UnloadOnClose to TRUE). IF HelpFileName = "" THEN MSGBOX "You must call the HelpRegister procedure before calling HelpShowTopic.", 0, "Help" EXIT SUB ELSE ' Register the Help file again. HelpRegister HelpFileName, HelpLoaded IF HelpLoaded = FALSE THEN MSGBOX "You must call the HelpRegister procedure before calling HelpShowTopic.", 0, "Help" EXIT SUB END IF END IF END IF ' Convert the topic request to uppercase to make ' matching easier then scan the HelpIndex table ' for that topic. ' RequestedTopic$ = UCASE$(ProvidedTopic$) TotalTopics = UBOUND(HelpIndexTopics) TopicNum = 1 EndNow = FALSE DO UNTIL EndNow IF UCASE$(HelpIndexTopics(TopicNum)) = RequestedTopic$ THEN EndNow = TRUE ELSE TopicNum = TopicNum + 1 IF TopicNum > TotalTopics THEN EndNow = TRUE TopicNum = 0 END IF END IF LOOP ' Exit if the topic does not exist. IF TopicNum = 0 THEN MSGBOX "Help topic '" + ProvidedTopic$ + "' not found.", 0, "Help" EXIT SUB END IF ' Seek to the topic's position in the Help file. SEEK HelpFileNum, HelpIndexPtr(TopicNum).StartFilePtr ' REDIM the topic array so that it's the exact size ' needed to store the requested topic. MaxLines = HelpIndexPtr(TopicNum).NumLines ON LOCAL ERROR GOTO HelpShowOutOfMemory REDIM Topic(1 TO MaxLines) AS STRING ' Load the topic lines into the topic array MaxLineLen = 0 FOR i = 1 TO MaxLines LINE INPUT #HelpFileNum, Topic(i) ' Convert tabs (CHR$(9)) to spaces. TabPos = INSTR(Topic(i), CHR$(9)) DO WHILE TabPos > 0 Topic(i) = LEFT$(Topic(i), TabPos - 1) + STRING$(TabSpaces - (TabPos MOD TabSpaces), " ") + MID$(Topic(i), TabPos + 1) TabPos = INSTR(TabPos + TabSpaces - 1, Topic(i), CHR$(9)) LOOP IF LEN(Topic(i)) > MaxLineLen THEN MaxLineLen = LEN(Topic(i)) NEXT i ON LOCAL ERROR GOTO 0 ' Set misc. values frmHelpMain.hscHelp.Value = 1 frmHelpMain.hscHelp.min = 1 frmHelpMain.hscHelp.max = HelpMax(MaxLineLen - frmHelpMain.pctBackground.ScaleWidth + 1, 1) frmHelpMain.vscHelp.max = HelpMax(MaxLines - frmHelpMain.pctBackground.ScaleHeight + 1, 1) frmHelpMain.vscHelp.Value = 1 frmHelpMain.vscHelp.min = 1 frmHelpMain.Caption = "Help: " + ProvidedTopic$ TopicCursor.Y = 0 IF frmHelpMain.ScaleHeight > 3 THEN frmHelpMain.vscHelp.LargeChange = frmHelpMain.pctBackground.ScaleHeight ' Update the history stack HelpTopicStackPtr = HelpTopicStackPtr + 1 ' Only store the last MaxHistoryStack of ' Help topics. IF HelpTopicStackPtr > MaxHistoryStack THEN 'Would overflow. Drop the least recent entry. FOR i = 2 TO MaxHistoryStack HelpTopicStack(i - 1) = HelpTopicStack(i) NEXT i HelpTopicStackPtr = MaxHistoryStack END IF ' Add this topic to the Help stack HelpTopicStack(HelpTopicStackPtr) = HelpIndexTopics(TopicNum) ' Enable/disable buttons based on the size of the ' Help stack SELECT CASE HelpTopicStackPtr CASE 1 ' This is the first topic. Both ' BACK (2) and History(3) should be ' disabled. frmHelpMain.cmdButtonBar(2).Enabled = FALSE frmHelpMain.cmdButtonBar(3).Enabled = FALSE CASE 2 ' This is the second topic. ' BACK (2) should be enabled but History(3) ' isn't necessary. frmHelpMain.cmdButtonBar(2).Enabled = TRUE frmHelpMain.cmdButtonBar(3).Enabled = FALSE CASE IS > 2 ' More than 2 topics have been shown so enabled ' both Back and History. frmHelpMain.cmdButtonBar(2).Enabled = TRUE frmHelpMain.cmdButtonBar(3).Enabled = TRUE END SELECT ' Restore the Help form to its former size/position ' if it is currently minimized. IF frmHelpMain.WindowState = 1 THEN frmHelpMain.WindowState = 0 END IF ' Refresh the form to ensure that new button bar ' states take effect. ' Actually display the topic, starting at ' the top and far left CursorPos.X = 0 CursorPos.Y = 0 HelpPrintText 1, 1 EXIT SUB HelpShowOutOfMemory: MSGBOX "Insufficient memory to display Help.", 0, "Help" HelpClose EXIT SUB END SUB 
