The charsetmodifier part in the Declare statement supplies the character set information for marshaling strings during a call to the external procedure.
Friend access is often the preferred level for an application's programming elements, and Friend is the default access level of an interface, a module, a class, or a structure.
The declaration statements are used to name and define procedures, variables, properties, arrays, and constants.
When you declare a programming element, you can also define its data type, access level, and scope. Statements calling a procedure, branching to another place in the code, looping through several statements, or evaluating an expression are executable statements.
The programming elements you may declare include variables, constants, enumerations, classes, structures, modules, interfaces, procedures, procedure parameters, function returns, external procedure references, operators, properties, events, and delegates. An assignment statement is a special case of an executable statement.
All these directives begin with #, and only white-space characters may appear before a directive on a line. Unlike C and C directives, they are not used to create macros. Net provides the following set of compiler directives: This directive is used for indicating a mapping between specific lines of source code and text external to the source.
It is used only by the compiler and the debugger has no effect on code compilation. Therefore, it has full access to all the libraries in the . NET, not only under Windows, but even Linux or Mac OSX. Net a widely used professional language: In this chapter, we will discuss the tools available for creating VB. Let us now briefly look into what do class, object, methods and instant variables mean. Let us look at an implementation of a Rectangle class and discuss VB. Write Line("Area: ", Get Area()) End Sub Shared Sub Main() Dim r As New Rectangle() r. Instance methods are invoked through an object of the class: Data types refer to an extensive system used for declaring variables or functions of different types. The following table shows all the data types available: Module Data Types Sub Main() Dim b As Byte Dim n As Integer Dim si As Single Dim d As Double Dim da As Date Dim c As Char Dim s As String Dim bl As Boolean b = 1 n = 1234567 si = 0.12345678901234566 d = 0.12345678901234566 da = Today c = "U"c s = "Me" If Script Engine = "VB" Then bl = True Else bl = False End If If bl Then 'the oath taking Console. Write Line("declaring on the day of: ", da) Console. Write Line("The Single: , The Double: ", si, d) End If Console. The Enum statement can be used at the module, class, structure, procedure, or block level. NET programs on Mono, the open-source alternative to . Objects of the same kind are said to have the same type or, more often, are said to be in the same class. Net program, it can be defined as a collection of objects that communicate via invoking each other's methods. Depending upon the design, it may need ways for accepting the values of these attributes, calculating area and displaying details. Read Line() End Sub End Class In previous chapter, we created a Visual Basic module that held the code. Shared methods or static methods can be invoked without creating an object of the class. Write Line("Lets see what happens to the floating point variables:") Console. The Enum statement declares an enumeration and defines the values of its members.The following code demonstrates a hypothetical use of the directive: Module mydirectives Public Class External Source Tester Sub Test External Source() #External Source("c:\vbprogs\directives.vb", 5) Console. ") #End External Source End Sub End Class Sub Main() Dim t As New External Source Tester() t. Write Line("Exam Questions for Class VII") #Else If class Code = 8 Then Console.Write Line("Exam Questions for Class VIII") #Else Console.This operator does not perform short-circuiting, i.e., it evaluates both the expressions. If any of the two operands is true, then condition becomes true.