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 DBEDIT()
 Browse records in a table layout
------------------------------------------------------------------------------
 Syntax

     DBEDIT([<nTop>], [<nLeft>],
        [<nBottom>], <nRight>],
        [<acColumns>],
        [<cUserFunction>],
        [<acColumnSayPictures> | <cColumnSayPicture>],
        [<acColumnHeaders> | <cColumnHeader>],
        [<acHeadingSeparators> | <cHeadingSeparator>],
        [<acColumnSeparators> | <cColumnSeparator>],
        [<acFootingSeparators> | <cFootingSeparator>],
        [<acColumnFootings> | <cColumnFooting>]) --> NIL

 Arguments

     <nTop>, <nLeft>, <nBottom>, and <nRight> define the
     upper-left and lower-right coordinates of the DBEDIT() window.  Row
     values can range from zero to MAXROW() and column positions can range
     from zero to MAXCOL().  If not specified, the default coordinates are 0,
     0, MAXROW(), and MAXCOL().

     <acColumns> is an array of character expressions containing database
     field names or expressions to use as column values for each row
     displayed.  If this argument is not specified, DBEDIT() displays all
     fields in the current work area as columns.

     <cUserFunction> is the name of a user-defined function that executes
     when an unrecognizable key is pressed or there are no keys pending in
     the keyboard buffer.  Specify the function name as a character
     expression without parentheses or arguments.  Note that the behavior of
     DBEDIT() is affected by the presence of this argument.  Refer to the
     discussion below for more information.

     <acColumnSayPictures> is a parallel array of picture clauses to
     format each column.  Specifying <cColumnSayPicture> instead of an array
     displays all columns with the same format.  Refer to TRANSFORM() or
     @...SAY for more information on pictures.

     <acColumnHeaders> is a parallel array of character expressions that
     define the headings for each column.  Specifying <cColumnHeader> gives
     the same heading for all columns.  To display a multi-line heading,
     embed a semicolon in the heading expression where you want the string to
     break.  If not specified, column headings are taken from the <acColumns>
     array or the field names in the current work area, if the <acColumns>
     argument is not specified.

     <acHeadingSeparators> is a parallel array of character expressions
     that define the characters used to draw horizontal lines separating
     column headings from the field display area. Specifying
     <cHeadingSeparator> instead of an array uses the same heading separator
     for all columns.  If this argument is not specified, the default
     separator is a double graphics line.

     <acColumnSeparators> is a parallel array of character expressions
     that define the characters used to draw vertical lines separating the
     columns.  Specifying <cColumnSeparator> instead of an array uses the
     same separator for all columns.  If this argument is not specified, the
     default separator is a single graphics line.

     <acFootingSeparators> is a parallel array of character expressions
     that define the characters used to draw horizontal lines separating
     column footings from the field display area.  Specifying
     <cFootingSeparator> instead of an array uses the same footing separator
     for all columns.  If this argument is not specified, there is no footing
     separator.

     <acColumnFootings> is a parallel array of character expressions that
     define footings for each column.  Specifying <cColumnFooting> instead of
     an array gives the same footing for all columns.  To display a multi-
     line footing, embed a semicolon in the footing expression where you want
     the string to break.  If this argument is not specified, there are no
     column footings.

 Returns

     DBEDIT() always returns NIL.

 Description

     DBEDIT() is a user interface and compatibility function that displays
     records from one or more work areas in a table form.  The DBEDIT()
     window display is a grid of cells divided into columns and rows.
     Columns correspond to database fields and rows correspond to database
     records.  Each column is defined by an element of the <acColumns> array.
     The display width of each column is determined by the evaluation of the
     column expression in <acColumns> array or the column picture specified
     in the <acColumnSayPictures> array.

     All cursor movement keys are handled within DBEDIT(), including Page up,
     Page down, Home, End, the four arrow keys, and all Ctrl key combinations
     that produce cursor movement.  The navigation keys that DBEDIT()
     responds to when a user function argument is not specified are listed in
     the Active Keys table below:

     DBEDIT() Active Keys
     ------------------------------------------------------------------------
     Key                 Action
     ------------------------------------------------------------------------
     Up arrow            Up one row
     Down arrow          Down one row
     Left arrow          Column left
     Right arrow         Column right
     Ctrl+Left arrow     Pan left one column
     Ctrl+Right arrow    Pan right one column
     Home                Leftmost current screen column
     End                 Rightmost current screen column
     Ctrl+Home           Leftmost column
     Ctrl+End            Rightmost column
     PgUp                Previous screen
     PgDn                Next screen
     Ctrl+PgUp           First row of current column
     Ctrl+PgDn           Last row of current column
     Return              Terminate DBEDIT()
     Esc                 Terminate DBEDIT()
     ------------------------------------------------------------------------

     When the user function argument (<cUserFunction>) is specified, all keys
     indicated in the Active Keys table are active with the exception of Esc
     and Return.  When DBEDIT() calls the user function, it automatically
     passes two arguments:

     .  The current mode passed as a numeric value

     .  The index of the current column in <acColumns> passed as a
        numeric value

     The mode parameter indicates the current state of DBEDIT() depending on
     the last key executed.  The possible mode values are listed in the
     DBEDIT() Modes table below:

     DBEDIT() Modes
     ------------------------------------------------------------------------
     Status  Dbedit.ch      Description
     ------------------------------------------------------------------------
     0       DE_IDLE        Idle, any cursor movement keystrokes have been
                            handled and no keystrokes are pending
     1       DE_HITTOP      Attempt to cursor past top of file
     2       DE_HITBOTTOM   Attempt to cursor past bottom of file
     3       DE_EMPTY       No records in work area
     4       DE_EXCEPT      Key exception
     ------------------------------------------------------------------------

     The index parameter points to the position of the current column
     definition in the <acColumns> array.  If <acColumns> is not specified,
     the index parameter points to the position of the field in the current
     database structure.  Access the field name using FIELD().

     A user-defined function must return a value that indicates to DBEDIT()
     the action to perform.  The User Function Return Values table below
     lists the possible return values and the corresponding actions:

     DBEDIT() User Function Return Values
     ------------------------------------------------------------------------
     Value   Dbedit.ch      Description
     ------------------------------------------------------------------------
     0       DE_ABORT       Abort DBEDIT()
     1       DE_CONT        Continue DBEDIT()
     2       DE_REFRESH     Force reread/repaint and continue; after repaint,
                            process keys and go to idle
     ------------------------------------------------------------------------

     A number of instances affect calls to the user function:

     .  A key exception occurs.  This happens when DBEDIT() fetches a
        keystroke that it does not recognize from the keyboard.  Any pending
        keys remain in the keyboard buffer until fetched within the user
        function or until DBEDIT() continues.

     .  DBEDIT() enters the idle mode (i.e., all pending keys have
        been processed).  This happens when the keyboard is empty or after a
        screen refresh.  In this instance, there is one call to the user
        function and then DBEDIT() waits for a key.

     .  Beginning or end of file is encountered.  This is the same as
        idle.  All executable keys are performed, and there is one call to
        the user function with the appropriate status message.

     Note that when DBEDIT() is first executed, all keys pending in the
     keyboard buffer are executed and then DBEDIT() enters the idle mode with
     a user function call.  If no keys are pending, the idle mode is
     immediate.

     The user function should handle all modes and status messages received
     from DBEDIT().

     A user-defined function must ensure that the DBEDIT() status is
     equivalent to DE_EXCEPT (4); otherwise, the value of LASTKEY() is
     meaningless and a Return value of DE_REFRESH (2) will place the
     application into an endless loop.  For example:

     FUNCTION DBEditFunc ( nMode, nColumnPos )
        LOCAL RetVal := DE_CONT

        IF ( nMode == DE_EXCEPT )
           IF ( LASTKEY() == K_F5 )
                    RetVal := DE_REFRESH
           ENDIF
        ENDIF
        RETURN(  RetVal )

     DBEDIT() is fully re-entrant, which means you can make nested calls to
     it.  Using this feature, you can have multiple browse windows on the
     screen at the same time.

     DBEDIT() is a compatibility function and, therefore, no longer
     recommended as a programmable browse facility.  As such, it is
     superseded by the TBrowse object class.  For more information, refer to
     TBrowse class in this chapter.

 Examples

     .  This example demonstrates a generic call to DBEDIT():

        USE Names NEW
        DBEDIT()

     .  This example demonstrates calling DBEDIT() with a user
        function:

        #include "dbedit.ch"
        #include "inkey.ch"

        // Array must be visible to other user-defined programs in
        // program

        STATIC acColumns := {}

        PROCEDURE Main()

           USE Names NEW
           INDEX ON Names->Lastname + Names->FirstName TO Names

           CLS

           acColumns := { "LastName", "FirstName" }

           DBEDIT( 5, 5, 20, 70, acColumns, "UserFunc" )

        RETURN


        FUNCTION UserFunc( nMode, nCol )
           LOCAL nKey := LASTKEY()
           LOCAL nRetVal := DE_CONT         // Default return value

           DO CASE
           CASE nMode == DE_IDLE
              nRetVal := IdleFunc()
           CASE nMode == DE_HITTOP
              TONE( 100, 3 )
           CASE nMode == DE_HITBOTTOM
              TONE( 100, 3 )
              nRetVal := AppendFunc( nKey )
           CASE nMode == DE_EMPTY
              nRetVal := EmptyFunc()
           CASE nMode == DE_EXCEPT
              nRetVal := ExceptFunc( nKey, nCol )
           OTHERWISE
              TONE( 100, 3 )
           ENDCASE

        RETURN nRetVal

        FUNCTION AppendFunc( nKey )
           LOCAL nRetVal := DE_CONT         // Default return value

           IF nKey == K_DOWN                  // If DOWN ARROW
              APPEND BLANK                  // Append blank record
        // Note: The appended record will appear at the top of the
        //       DBEDIT() screen when the database file is indexed.

              nRetVal := DE_REFRESH         // Refresh screen
           ENDIF


        RETURN nRetVal

        FUNCTION ExceptFunc( nKey, nCol )
           LOCAL nRetVal := DE_CONT         // Default return value

           DO CASE
           CASE nKey == K_ESC                  // If ESCAPE
              nRetVal := DE_ABORT               // Exit
           CASE nKey == K_RETURN               // If RETURN
              nRetVal := EditFunc( nCol )      // Function to edit
                                               // field

           // Toggle DELETED status
           CASE nKey == K_DEL .AND. LASTREC() != 0  // DELETE pressed
              IF DELETED()
                 RECALL
              ELSE
                 DELETE
              ENDIF
           OTHERWISE
                 TONE( 100, 1 )
           ENDCASE

        RETURN nRetVal


        FUNCTION EditFunc( nCol )
           LOCAL cIndexVal         // Value of current key expression
           LOCAL nRetVal            // Return value
           LOCAL nField            // Position of current field
           LOCAL cFieldVal         // Value of current field
           LOCAL nCursSave         // Preserve state of cursor

           // This will return an error if no index is open
           cIndexVal := &( INDEXKEY(0) )

           nField := FIELDPOS( acColumns[nCol] )

           IF nField != 0
              nCursSave := SETCURSOR()         // Save state of cursor
              SETCURSOR(1)                     // Change cursor shape
              cFieldVal := FIELDGET( nField )         // Save contents
                                                     // of field
              @ ROW(), COL() GET cFieldVal            // GET new value
              READ
              FIELDPUT( nField, cFieldVal )            // REPLACE with
                                                     // new value
              SETCURSOR( nCursSave )                  // Restore cursor
                                                     // shape
           ENDIF


           IF cIndexVal != &( INDEXKEY(0) )         // If key expression

                                                  // changed
              nRequest := DE_REFRESH               // Refresh screen
           ELSE                                    // Otherwise
              nRequest := DE_CONT                  // Continue
           ENDIF

        RETURN nRequest

        FUNCTION IdleFunc()
           // Idle routine
        RETURN DE_CONT

        FUNCTION EmptyFunc()
           // Empty Records routine
        RETURN DE_CONT

 Files   Library is EXTEND.LIB, header files are Dbedit.ch and Inkey.ch.