Learning C# 3.0

Method Arguments

The behavior of a class is defined by the methods of that class. To make your methods as flexible as possible, you can define parameters: information passed into the method when the method is invoked. Thus, rather than having to write one method when you want to sort your listbox from A to Z, and a second method when you want to sort it from Z to A, you define a more general Sort( ) method and pass in a parameter specifying the order of the sort.

Methods can take any number of parameters. The parameter list follows the method name and is enclosed in parentheses. Inside the parentheses, you provide the type of the parameter and the name that the method will use to refer to that parameter.

Tip

The terms argument and parameter are often used interchangeably, though some programmers insist on differentiating between the parameter declaration and the arguments passed in when the method is invoked.

For example, the following declaration defines a method named MyMethod( ) that returns void (that is, it returns no value at all) and takes two parameters (an int and a Button):

void MyMethod (int firstParam, Button secondParam)
{
   // ...
}

Within the body of the method, the parameters act as local variables, as though you had declared them in the body of the method and initialized them with the values passed in. Example 7-2 illustrates how you pass values into a method; in this case, values of type int and float.

Example 7-2. To pass parameters into a method, you include them in parentheses ...