C# 0 The Complete Reference

The Form Class

A form is created by instantiating an object of the 

Form

 class or of any class derived from 

Form

.

Form

 contains significant functionality of its own, and it inherits additional functionality. 

Two of its most important base classes are 

System.ComponentModel.Component

, which 

supports the .NET component model, and 

System.Windows.Forms.Control

. The 

Control

class defines features common to all Windows controls. Because 

Form

 inherits 

Control

, it, 

too,

is a control. This fact allows forms to be used to create controls. Several of the members of 

Form

 and 

Control

 are used in the examples that follow.

A Skeletal Form-Based Windows Program

We will begin by creating a minimal form-based Windows application. This application 

simply creates and displays a window. It contains no other features. However, this skeleton 

does show the steps necessary to construct a fully functional window. This framework is the 

starting point upon which most types of Windows applications will be built. The skeletal 

form-based Windows program is shown next.

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// A form-based Windows Skeleton.

using System;

using System.Windows.Forms;

// WinSkel is derived from Form.

class WinSkel : Form {

  public WinSkel() {

    // Give the window a name.

    Text = "A Windows Skeleton";

  }

  // Main is used only to start the application.

  [STAThread]

  static void Main() {

    WinSkel skel = new WinSkel(); // create a form

    // Enable visual styles.

    Application.EnableVisualStyles();

    // Start the window running.

    Application.Run(skel);

  }

}

The window created by this program is shown in Figure 26-1. Let’s examine this 

program line-by-line. First, notice that both 

System

 and 

System.Windows.Forms

 are 

included.

System

 is needed because of the 

STAThread

 attribute that precedes 

Main( )

.

System.Windows.Forms 

supports the Windows Forms subsystem, as just explained.

Next, a class called 

WinSkel

 is created. It inherits 

Form

. Thus, 

WinSkel

 defines a 

specific type of form. In this case, it is a minimal form.

Inside the 

WinSkel

 constructor is the following line of code:

Text = "A Windows Skeleton";

Text

 is the property that sets the title of the window. Thus, this assignment causes the title 

bar in the window to contain 

A Windows Skeleton

.

Text

 is defined like this:

public override string Text { get; set; }

F

IGURE

 26-1 

The skeletal form-

based window

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