C# Methods: Definition, Calling, Parameters

Objectives

• Learning the components of a method is important
• Calling class methods can be done, both with and without parameters
• Predefined methods are available in the Console and Math classes for use.
• Value, ref, and out parameter types, must be distinguished
• Custom value and non-value-returning class methods can be written with and without parameters
• Named and optional parameters with default values are available for use
• A programming example will illustrate the lesson's concepts

Anatomy of a method

• Methods are defined inside classes
• Methods group program statements based on functionality, they can then be called one or more times
• All programs consist of at least one method
• All programs consist of the Main() which is a user-defined method

Access Modifiers

• Public access modifiers have no restrictions
• Protected is limited to the containing class, or the class derived from the containing class
• Internal is limited to the current project
• Protected internal is limited to the current project derived from a class
• Private is limited to containing class

Return Types

• What type of value is returned when the method is completed is indicated by the return types
• Return types are always listed immediately before method name
• Void means no value being returned
• All non-void methods require a return statement with a compatible value

Method Names

• Rules for creating an identifier must be followed
• Pascal case style should be used
• Action verb or prepositional phrase
• Example names include: CalculateSales Tax(), AssignSectionNumber(), DisplayResults(), InputAge(), ConvertInputValue()

Parameters

• Parameters supply unique data to method, appearing inside parentheses
• Data type and an identifier are included
• Reference values using identifier name are in the method body
• "Parameter" refers to items appearing in the heading, while "argument" refers to items appearing in the call
• Formal parameters and actual arguments are types

Method Body

• Enclosed in curly braces
• Include statements ending in semicolons
• Variables are declared
• Arithmetic is performed
• Other methods called
• Value-returning methods must include return statement

Calling Class Method

• Invoke a method
• A call to a method that returns no value uses the syntax: [qualifier].MethodName(argumentList)
• Qualifier syntax is square brackets around the qualifier indicating it is optional
• The qualifier can be a class or object name
• The call to method does not include data type
• IntelliSense makes it easy

Forms, Label and Group Box

• The content covers forms, labels, and group boxes in Week 2

Form Class

• The form class can represent any window displayed in an application
• It can create standard, tool, borderless, and floating windows
• It can create modal windows like a dialog box
• The form class can determine the appearance, size, color, and window/dialog box appearance
• It enables responding to actions on the form

Form, Solution Explorer and Properties

• Using the Form, you can navigate the Solution Explorer and set Properties.

Label Class

• Can be used to provide descriptive text for a control
• Descriptive text can be added to a form to provide the user with helpful information
• Runtime information on the status of an application can be displayed

GroupBox Class

• A frame can be displayed around a group of controls with or without a cation
• A collection of controls on a form can be grouped
• A container control can be used to define group of controls
• A group box is typically used to contain a logical group of RadioButton

Form.Load Event

• Before a form is displayed for the first time, the event occurs
• An example snippet to execute when the form loads is :private void Form1_Load(object sender, System.EventArgs e) { count += 1; }

Explore C# methods, their components, and how to call them with or without parameters. Understand predefined methods in the Console and Math classes, value, ref, and out parameter types. Learn to write custom methods with named and optional parameters.