C# & VB.NET Conversion Pocket Reference

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C# & VB.NET Conversion Pocket Reference

always set this option to On, and it is now (actually for the

first time in VB’s history) set to On by default. There is no

equivalent in C# for this feature.

The second setting is Option Strict. This is a new setting for

VB developers. If you set Option Strict to Off, you do not

need to assign a type to your variables. In other words, it is

perfectly legal to write code that says:

Dim Acct = New CChecking( )

In that case, Acct will be of type System.Object. This feature

has two other side effects. One is that with Option Strict On,

the compiler will issue a compile-time error if it detects a nar-

rowing conversion or if it cannot guarantee that the conver-

sion will succeed. The developer can fix the error by using an

explicit cast. In VB explicit casts are done with the CType

function or an equivalent. (See “Type Comparison and Con-

version” in the “Syntax Differences” section for a full expla-

nation.) The only reason this option should be set to off is to

use late binding (see “Late Binding (VB)” in the “Unique

Language Features” section for details).

The third option in VB.NET, Option Compare, was

explained in detail in the “String Comparisons” section.

Errors and Warnings

Both compilers generate errors (of course), and both gener-

ate warnings as well, but the C# compiler can generate dif-

ferent types of warnings. Warnings come in different levels, 0

through 4. Warning level 0 means that no warnings are

reported. Warning level 1 means that only severe warnings

are reported.

VB.NET projects let you set the warning level to either 0 or

1. This is controlled through Project Properties

➝ Configura-

tion Properties

➝ Build ➝ Enable build warnings (checked by

default). C# lets you set the warning level through Project

Properties

➝ Configuration Properties ➝ Build ➝ Warning