lockRow( ) example

The following checks to see if the current row has been changed before the user navigates to another row. If changes have been made, an explicit row lock is attempted. If the lock is successful, the date and time of update is recorded in the row, the row is saved and unlocked, and navigation is permitted. If unsuccessful, the user is given a choice as to what to do.

function rowset_canNavigate

   if not this.modified 

      return true       // No changes, row navigation okay 

   endif 

   local lReturn, nButton 

   lReturn = false 

   do 

      if not this.lockRow( )   // Try the lock 

         nButton = msgBox( "Row is locked by another, keep trying? " + ; 

         '("Cancel" discards changes)', ; 

         "Cannot Save Changes", 3 + 32 ) 

         if nButton = 6 

            loop        // User clicked "Yes" (try again) 

         endif 

         lReturn := nButton = 2 

         if lReturn      // User clicked "Cancel" 

            this.abandon( ) 

         endif 

         exit         // Give up 

      endif 

      lReturn := true 

      this.fields[ "UPDATED" ].value := date( ) + " at " + time( ) 

      this.save( ) 

      this.unlock( ) 

   until lReturn 

return lReturn