VB'Net Language Basics

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VB.Net Language Basics

• R. Johnson ITE 285

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Comments

• Comments are text we want compiler to ignore
  are NOT executable statements
• VB comments indicated with single-quote
  (apostrophe) and are green in IDE
• I expect comments for identifying yourself,
  assignment, purpose, and elsewhere for clarity
• There is no block comment like //
• Older code may use REM (remark)

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Variable Declarations

• Associate a variable name to be used with a data
  type
• Form Dim name As type
• May have Const, Private or Public instead of Dim
• Initialize Dim strName As String Joe
• Effectively not case-sensitive IDE keeps case
  consistent w/ declaration

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VB.Net Data Types
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Literal Values

• 4 Integer
• 4.24 Double
• John String
• y Char from context
• 3/1/2006 Date

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Operators

• Assignment
• Arithmetic
• Relational (comparison)
• Logical
• Dot operator

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Assignment

• The serves exact function as in Java
• In an expression such as yy1
• Right hand side is evaluated
• Result is copied to left hand side variable

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Arithmetic Operators

• Addition
• - Subtraction
• Multiplication
• / Division
• \ Integer Division
• Mod Modulus or remainder (like Java )
• Operator precedence is similar to Java, ( ) to
  override it.

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Relational Logical Operators

• Equality test with (not )
• Not Equal ltgt instead of !
• gt, lt, gt, lt just like Java
• AND instead of
• OR instead of
• NOT instead of !

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Calling Procedures

• A procedure is like a Java method
• Sub (short for subroutine) is like a Java void
  method.
• A Sub call is always a standalone statement.
• Function is like a Java method that returns a
  result that replaces the call in the larger
  expression.

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Event Handling Procedures

• For now we write most of our code in Event
  Handling Procedure Subs.
• Similar to Java ActionListener
• We never call these directly
• Instead .NET passes event from interface, calling
  our Event Handler Sub when needed.
• Handles event list can respond to more than one
  event.

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Built-In Functions

• Many functions follow OOP paradigm
• string methods, e.g. Name.IndexOf(i)
• Math functions e.g. Math.Sin(x)
• Intrinsic functions are standalone
• Val(mystring), CDbl(mystring), CInt(mystring)
• IsNumeric( mystring)
• FormatNumber(x, 2)
• Financial functions, random numbers