Cross Ref > Language Basics

VB.Net is not case sensitive. If you type any other case for commands or variables, VB.Net will change it to the accepted or defined case. For example, if you type messagebox.show it is converted to MessageBox.Show.

Syntax Example:   The following code works: MessageBox.Show("hello")

Same as standard C++. Both are case sensitive. In C and C++ commands and variable names are case sensitive.

MessageBox::Show("Hello");

messagebox::SHOW("Hello"); //>>>Does not work!

VB.Net, like VB Classic code blocks, are surrounded by statement ending keywords that all use End such as End Class, End Sub, End Function, and End If.

Public Class Dog

End Class

Protected Sub MySub

End Sub

Public Shared Function MySharedFunction() As Integer
 MySharedFunction = 12345
End Function 

If x Then

End If

Same as standard C++. For C++, Java, JavaScript, and PHP, I prefer to put the first { at the end of the first line of the code block as in the example above because I see more C++ formatted that way.

class Cyborg {
public: System::Void IntroduceYourself() {
    MessageBox::Show("Hi");
  }
};

Commenting Code
VB.Net, like all the VB-based languages, uses a single quote (') or the original class-style basic "REM" (most developers just use a quote). VB.Net does NOT have a multiple line comment.

'Single line comment.
 

REM Old school single line comment.

 VB.Net Comments (' or REM)  

Commenting Code
Same as standard C++. C++ uses "//" for a single line comment and /* */ for a multiple line comment.

//Single line comment in MS (not ANSI compliant so do NOT use).
  

/* ANSI compliant single line comment. */
  

/*
Multiple line
comment.

*/

/*

* This is another popular

* way to write multi-line

* comments.

*/

In VB.Net, you define constants with the Const keyword.

All constants are part of a class (no global constants) but you can make a constant public and have access to it using ClassName.ConstantName so long as you have added the class to the project. This works even without creating the class as if the public constants were static, but you cannot use the Shared keyword.

Constants must be of an integral type (sbyte, byte, short, ushort, int, uint, long, ulong, char, float, double, decimal, bool, or string), an enumeration, or a reference to null.

Public Class Convert
  Inherits System.Object

  Public Const kName As String = "Mike"

  Private Const kPI Double = 3.1459

  //Declare two or more on same line too:
  Const kFeetToMeter = 3.2808, kMeterToFeet = 0.3048
End Class

 VB.Net Constants (Const kPI Double = 3.1459)  

C++/CLI supports the const and static const keywords of standard C++ as well as the new literal keyword. A literal is equivalent to static const in standard C++ and Microsoft's documentation recommends to replace static const with the new literal keyword because a literal is available in metadata; a static const variable is not available in metadata to other compilers.

You can use static const within the class declaration or locally within a method. However, literal is only valid in the class declaration section and const is only valid within a method.

Syntax Example:   //some method { const String^ MyName = "John"; static const Int32 MyAge = 27; //} // public class SomeClass : public Object { public:   literal double Pi = 3.14159;   literal String^ MyName = "Mike";   static const Int32 MyAge = 35; //...

 Ref: http://msdn.microsoft.com/en-us/library/ms235301(VS.80).aspx

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 " _".

Syntax Example:   Console.WriteLine("Hello1") Console.WriteLine("Hello2") Console.WriteLine("Hello3") 'The following commented code 'on a single line does not work... 'Console.WriteLine("Hello4") Console.WriteLine("Hello5") 'Two or more lines works too with a space+underscore: Console.WriteLine _ "Hello6";

Same as standard C++. C++ uses a semicolon ";" as an end of statement specifier and you can put multiple statements on a single line of code if you wish as well as split a single statement into two or more code lines.

//.Net WinForms example.

//Add, using namespace System::Windows::Forms;

MessageBox::Show("Hello1");

MessageBox::Show("Hello2");

MessageBox::Show("Hello3");

MessageBox::Show("Hello4"); MessageBox::Show("Hello5"); 

MessageBox:: 

  Show 

    ("Hello6");

String literals are quoted as in "Prestwood". If you need to embed a quote use two quotes in a row.

To specify a floating point literal between 1 and -1, preceed the decimal with a 0. If you don't, the compiler will auto-correct your code and place a leading 0. It will change .1 to 0.1 automatically. Trailing decimals are not allowed.

Syntax Example:   Console.WriteLine("Hello") Console.WriteLine("Hello ""Mike"".") 'Does VB.Net evaluate this simple 'floating point math correctly? No!  If (.1 + .1 + .1) = 0.3 Then MsgBox "Correct" Else MsgBox "Not correct" End If

Same as standard C++. String literals are quoted as in "Prestwood". If you need to embed a quote use a slash in front of the quote as in \".

To specify a floating point literal between 1 and -1, you can preceed the decimal with a 0 or not (both work). In other words, preceding and following decimals are allowed (both .1 and 0.1). Trailing decimals are also allowed (1, 1., and 1.0 are all equivalent and allowed).

MessageBox::Show("Hello");

MessageBox::Show("Hello \"Mike\".");

//Does ASP evaluate this simple

//floating point math correctly? No! 

if ((.1 + .1 + .1) == 0.3) {
  MessageBox::Show("Correct");
} else {
  MessageBox::Show("Not correct");
}

Variables are case sensitive but VS.Net will auto-fix your variable names to the defined case. You can declare variables in-line wherever you need them and declarative variable assignment is supported.

Syntax Example:   Dim FullName As String Dim Age As Integer Dim Weight As Double FullName = "Mike Prestwood" Age = 32 Weight = 154.4 'Declaritive variable assignment: Dim Married As String = "Y" MsgBox(Married)