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// If the value from GetIntFromDatabase() is null,

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// assign local variable to 100.

int? myData = dr.GetIntFromDatabase() ?? 100;

Console.WriteLine("Value of myData: {0}", myData.Value);

Console.ReadLine();

}

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Source Code

The NullableTypes application is located under the Chapter 4 subdirectory.

Summary

This chapter began with an examination of several C# keywords that allow you to build custom

methods. Recall that by default, parameters are passed by value; however, you may pass a para-

meter by reference if you mark it with ref. or out. You also learned about the role of optional

parameters and how to define and invoke methods taking parameter arrays.

Once we investigated the topic of method overloading, the bulk of this chapter examined sev-

eral details regarding how arrays, enumerations, and structures are defined in C# and represented

within the .NET base class libraries. Along the way, you examined several details regarding value

types and reference types, including how they respond when passing them as parameters to meth-

ods, and how to interact with nullable data types using the ? and ?? operators. With this, our initial

investigation of the C# programming language is complete! In the next chapter, we will begin to dig

into the details of object-oriented development.

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Defining Encapsulated Class Types

I

n the previous two chapters, you investigated a number of core syntactical constructs that are

commonplace to any .NET application you may be developing. Here, you will begin your examina-

tion of the object-oriented capabilities of C#. The first order of business is to examine the process of

building well-defined class types that support any number of constructors. Once you understand

the basics of defining classes and allocating objects, the remainder of this chapter will examine the

role of 

encapsulation. Along the way you will understand how to define class properties as well as

the role of static fields and members, read-only fields, and constant data. We wrap up by examining

the role of XML code documentation syntax.