When an object instance is destroyed, VB6 calls a special parameter-less sub named Class_Terminate. For example, when the variable falls out of scope. Since you cannot specify parameters for this sub, you also cannot overload it.
When an object instance is created from a class, VB6 calls a special sub called Class_Initialize.
Commenting Code VB Classic, like all the VB-based languages, uses a single quote (') or the original class-style basic "REM" (most developers just use a quote). VB Classic does NOT have a multiple line comment.
Directives - #
Directives are sometimes called compiler or preprocessor directives. A # is used for directives within VB Classic code. VB Classic offers only an #If..then/#ElseIf/#Else directive.
VB Classic is a loosely typed language. Declaring variables is optional unless you use the Option Explicit statement to force explicit declaration of all variables with Dim, Private, Public, or ReDim. Using Option Explicit is strongly recommended to avoid incorrectly typing an existing variable and to avoid any confusion about variable scope.
Undeclared variables are variants. To specifically declare a variant, use:
Dim x As Variant
Common data types include Byte (0..255), Boolean, Integer (2-byte integers), Long (4-byte integers), Currency, Single (32-bit number), Double (64-bit number), Date, String, and variant.
Variables declared with Dim at the module level are available to all procedures within the module. At the procedure level, variables are available only within the procedure.
VB classic uses the keywords sub and function. A sub does not return a value and a function does. Many programmers like to use the optional call keyword when calling a sub to indicate the call is to a procedure.
Short-circuit evaluation is a feature of most languages where once an evaluation evaluates to False, the compiler evaluates the whole expression to False, exits and moves on to the next code execution line. In VB Classic, the if statement does not support short-circuit evaluation but you can mimic it. Use either an if..else if..else if statement or nested if statements. You will find that your code that makes use of this technique will be clearer and easier to maintain than the short-circuit equivalent and faster than ingnoring the issue.
In coding languages, common End of statement specifiers include a semicolon and return (others exist too). Also of concern when studying a language is can you put two statements on a single code line and can you break a single statement into two or more code lines.
VB Classic End of Statement
A return marks the end of a statement and you cannot combine statements on a single line of code. You can break a single statement into two or more code lines by using a space and underscore " _".
In VB Classic, you have to add an empty string to the value being compared in order to get consistent results. For example, add &"" to your string varilable or it's code equivalent &vbNullString. Then compare to an empty string or verify it's length to 0 with Len.