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Chapter 5: Creating and Building Projects 135
Most of the VB and C# compiler options are similar, except for Option Explicit,
Option Strict, Option Compare, and Option Infer. In VB, variable declaration before use
can be turned off. When Option Explicit is on, you must declare any variables before use.
You can also assign any type to another by default, but Option Strict, if turned on, will
force you to use code that performs a conversion from a larger type to a smaller type,
often referred to as a narrowing conversion.
Option Compare causes comparison of strings to be done in a binary fashion. However,
when working with different languages, you’ll want to consider changing Option Compare to
text so that the comparison will consider culture-specific issues affecting string comparisons.
Option Infer will allow a variable to assume its type based on what is being assigned to the
variable, rather than explicitly declaring the variable type. Here’s an example of interred type
on a variable:
Dim studentName = "Joe"
In this example, the type of "Joe" is clearly a String. Since Option Infer is turned on, this
syntax is valid and studentName becomes a String because that is the type of the value
being assigned.
Figure 5-11 The VB Compile Options page