WITH OBJECT

WITH OBJECT

Identifies an object to receive multiple messages.

Syntax

       WITH OBJECT <object>
          :<message1>
          [<statements>]
          [:<messageN>]
       END

Arguments

WITH OBJECT <object> <object> is the symbolic name of a variable that holds a reference to an object. The object is to receive messages in the WITH OBJECT control structure.

:<message> All expressions that begin with the send operator in the OBJECT WITH block are sent as messages to <object>.

Description

The WITH OBJECT control structure delimits a block of statements where the object variable <object> receives multiple messages in abbreviated form. The name of the object variable can be omitted from a message sending expression, so that only the send operator (:) followed by the message to send must be typed.

WITH OBJECT basically relieves a programmer from typing. The name of the object variable is typed only once at the beginning of the WITH OBJECT block, and all subsequent messages sent to the object start with the send operator, omitting the object’s variable name.

Example

       // The example builds a simple database browser using a TBrowse object.
       // The columns added to the object and the cursor navigation logic is
       // programmed using the WITH OBJECT control structure.
       #include "inkey.ch"
       PROCEDURE Main
          LOCAL oTBrowse, aFields, cField, nKey
          USE Customer
          aFields := Array( FCount() )
          AEval( aFields, {|x,i| aFields[i] := FieldName(i) } )
          oTBrowse := TBrowseDB()
          WITH OBJECT oTBrowse
             FOR EACH cField IN aFields
                :addColumn( TBColumnNew( cField, FieldBlock( cField ) ) )
             NEXT
          END
          nKey := 0
          DO WHILE nKey <> K_ESC
             WITH OBJECT oTBrowse
                DO WHILE .NOT. :stabilize()
                ENDDO
                nKey := Inkey(0)
                SWITCH nKey
                   CASE K_UP
                     :up()       ; EXIT
                   CASE K_DOWN
                     :down()     ; EXIT
                   CASE K_LEFT
                     :left()     ; EXIT
                   CASE K_RIGHT
                     :right()    ; EXIT
                   CASE K_PGUP
                     :pageUp()   ; EXIT
                   CASE K_PGDN
                     :pageDown() ; EXIT
                   CASE K_HOME
                     :home()     ; EXIT
                   CASE K_END
                     :end()      ; EXIT
                END
             END
          ENDDO
          CLOSE Customer
       RETURN

Seealso

CLASS, METHOD

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One response to “WITH OBJECT

  1. Pingback: Harbour Statements | Viva Clipper !

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