PROCEDURES AND MODULES

• Event-handling procedures (or event handlers)


  Sub procedures that execute in response to an event raised by user action or by an occurrence in a program
• Function procedures


  Return a value to the calling code. They can perform other actions before returning the value.
• Sub procedures


  Perform actions but do not return a value to the calling code
• ByVal


  (Default) Accepts a copy of the data from the local variables. No changes are made to the contents of the local variables when the calling procedure resumes the control of execution.
• ByRef


  Accepts a reference of the data in the memory. The called procedure is granted read/write access to the local variable of the calling procedure.
• Parameter


  A value that the procedure expects you to pass when you call it. The procedure's declaration defines its parameters.
• Argument


  Represents the value that you pass to a procedure parameter when you call the procedure.
• Returning Control from Procedures

  Procedure only returns control to the calling code when it has finished running using Return, Exit, or End statements
• Modules


  A special file that has a .vb name extension and contains variable declarations and procedures that can be used ANYWHERE in the program
• Knowledge of event handlers, sub procedures and modules gives Visual BASIC programmers an effective tool to use to create more efficient and systematized codes
• Learn how to use them by familiarizing the functions which were detailed in this lecture and putting them into practice
• Someone who is knowledgeable about something not only knows the what, but most importantly, the when, the how, and the why
• Procedures


  It is a self contained block and a set of executable statements.
• Event Handlers


  event within a program
• Sender


  Parameters of event handlers where the object is causing an event
• e


  Parameters of event handlers where there is a specific action