Stephens' C# Programming with Visual Studio® 2010 24-Hour Trainer

274

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LESSON 23 Defining Classes

code asserts that the new value is between 0 and 359 degrees. The program can continue correctly if

the value is outside of this range so the code uses

Debug.Assert instead of throwing an exception.

// The Turtle’s direction in degrees.

private int direction = 0; // Backing field.

public int Direction

{

get { return direction; }

//set { direction = value; }

set

{

Debug.Assert((value >= 0) && (value <= 359),

“Direction should be between 0 and 359 degrees”);

direction = value;

}

}

Property accessors also give you a place to set break-

points if something is going wrong. For example, if

you know that some part of your program is setting

a

Turtle’s Direction to 45 when it should be set-

ting it to 60 but you don’t know where, you could set

a breakpoint in the

set accessor to see where the

change is taking place.

TRY IT

In this first Try It in the lesson, you cre-

ate a simple

Person class with FirstName,

LastName, City, Street, and Zip properties,

some having simple validations. You also build

a simple test application shown in Figure 23-1.

You can download the code and resources for this Try It from the book’s web

page at

www.wrox.com or www.CSharpHelper.com/24hour.html. You can find

them in the TryIt23a folder in the Lesson23 folder of the download.

Lesson Requirements

Build the program shown in Figure 23-1.



Create a



Person class.

Make auto-implemented properties ...