Introduction  Instantiation  Events & Event Handlers   Global Methods & Properties 
Messages  Hints,Tips & Code  Links & Glossary  Two Demo Projects  Flow Diagram

MESSAGES

     A Message is an item of Data sent from one RB Instance to another (or, in ordinary words, from one RB Object to another) to cause an effect. In the image below, the Message being sent to Window2 is "Set your Title called "Property" to the text "Book List". In the second, it is being sent to the Object (which must be in the current window) called "Target" and the Message is "Execute the Method called 'Explode' ". (In other words, "Go on - Explode".)

     Many things happen within an RB program by means of Messages sent to Instances of Objects. Messages connect all the Objects in an RB program together. Some Messages are sent "secretly" by RB without you knowing about them (except for their effect). For example, when (eg.), the user presses a window's "Close" button, RB triggers an Open Window Event and sends a Message to execute the code (if you have written any) in the corresponding Event Handler. A beginner does not need to know anything more about these secret Messages. Other messages are explicitly sent by code that you write. For example, while the Open Window Event mentioned starts to execute its Event Handler, the code in it might send a message to open another window, or add text to a Static Text Control in another window.

     There are two types of Messages:

Type 1. It can Refer to a Property (and Properties can be considered to be Variables); or

Type 2. It can Refer to a Method (or as Function).

     An example of Type 1 is the top one in the above image, and a Type 2 example is the bottom one.

Longdistance Messages

     If some code is written in (say) Window1's Source Code that is required to send a Message to Window2 to affect something in Window2, then that Message must include the word "Window2" (no quotation marks) to ensure that it will be sent to Window 2. For example:

     An analogy is an office where workers pass Messages to each other by delivering them personally (if the recipient is in the same room). But if the recipient is not, the envelope must add the name of the other room so that the clerk knows where to deliver it.

The App Class

     For advice on sending Massages to the App Class, please see the Global Methods and Properties page.

Flow Diagram

     To see how Messages connect Objects together, please see the Flow Diagram.

Introduction  Instantiation  Events & Event Handlers   Global Methods & Properties 
Messages  Hints,Tips & Code  Links & Glossary  Two Demo Projects  Flow Diagram