Windows フォームでのコントロールの使用方法の概要Overview of Using Controls in Windows Forms

このトピックでは、Windows フォーム アプリケーションの重要な要素について説明し、コントロールを使用して Windows フォーム アプリケーションでイベントを処理する簡単な例を提供します。This topic describes the essential elements of a Windows Forms application and provides a simple example that uses controls and handles events in a Windows Forms application.

単純な Windows フォーム アプリケーションSimple Windows Forms Applications

少なくとも、Windows フォーム アプリケーションは、次の要素で構成されます。At a minimum, a Windows Forms application consists of the following elements:

  • 1 つまたは複数のクラスから派生したSystem.Windows.Forms.Formします。One or more classes that derive from System.Windows.Forms.Form.

  • AMainメソッドを呼び出す、 static (shared Visual Basic で)Runメソッドを呼び出し、Formのインスタンス。A Main method that invokes the static (shared in Visual Basic) Run method and passes a Form instance to it. Runメソッドは、オペレーティング システムからアプリケーションへのメッセージを処理します。The Run method processes messages from the operating system to the application.

次のコード例では、Windows フォーム アプリケーションの重要な要素を示します。The following code example shows the essential elements of a Windows Forms application.

Option Explicit  
Option Strict  
  
Imports System  
Imports System.Windows.Forms  
  
Public Class MyForm  
   Inherits Form  
  
   Public Sub New()  
      Me.Text = "Hello World"  
   End Sub 'New  
  
   <STAThread()> _  
   Public Shared Sub Main()  
      Dim aform As New MyForm()  
      ' The Application.Run method processes messages from the operating system   
      ' to your application. If you comment out the next line of code,   
      ' your application will compile and execute, but because it is not in the  
      ' message loop, it will exit after an instance of the form is created.  
      Application.Run(aform)  
   End Sub  
End Class  
using System;  
using System.Windows.Forms;  
  
public class MyForm : Form {  
  
   public MyForm() {  
      this.Text = "Hello World";  
   }  
   [STAThread]  
   public static void Main(string[] args) {  
     MyForm aform = new MyForm();  
// The Application.Run method processes messages from the operating system   
// to your application. If you comment out the next line of code,   
// your application will compile and execute, but because it is not in the // message loop, it will exit after an instance of the form is created.  
      Application.Run(aform);  
   }  
}  

Windows フォーム アプリケーションでコントロールを使用します。Using Controls in a Windows Forms Application

次のコード例では、Windows フォーム アプリケーションのコントロールを使用してし、イベントを処理する方法を説明する簡単なアプリケーションを示します。The following code example shows a simple application that illustrates how Windows Forms applications use controls and handle events. フォームの 3 つのボタンの例で構成されます。各ボタンがクリックされたときに背景色を変更します。The example consists of three buttons on a form; each button changes the background color when clicked.

Option Explicit  
Option Strict  
  
Imports System  
Imports System.ComponentModel  
Imports System.Windows.Forms  
Imports System.Resources  
Imports System.Drawing  
  
Public Class MyForm  
   Inherits Form  
   Private red As Button  
   Private blue As Button  
   Private green As Button  
  
   Public Sub New()  
      InitializeComponent()  
   End Sub  
  
   Protected Overloads Overrides Sub Dispose(disposing as Boolean)  
      MyBase.Dispose(disposing)  
   End Sub  
  
   ' InitializeComponent is a helper method for the constructor.   
   ' It is included for consistency with code that is   
   ' auto-generated by the Windows Forms designer in Visual Studio.   
   Private Sub InitializeComponent()  
  
      ' Creates three buttons, sets their properties, and attaches  
      ' an event handler to each button.  
      red = New Button()  
      red.Text = "Red"  
      red.Location = New Point(100, 50)  
      red.Size = New Size(50, 50)  
      AddHandler red.Click, AddressOf button_Click  
      Controls.Add(red)  
  
      blue = New Button()  
      blue.Text = "Blue"  
      blue.Location = New Point(100, 100)  
      blue.Size = New Size(50, 50)  
      AddHandler blue.Click, AddressOf button_Click  
      Controls.Add(blue)  
  
      green = New Button()  
      green.Text = "Green"  
      green.Location = New Point(100, 150)  
      green.Size = New Size(50, 50)  
      AddHandler green.Click, AddressOf button_Click  
      Controls.Add(green)  
   End Sub  
  
   ' Event handler.  
   Private Sub button_Click(sender As Object, e As EventArgs)  
      If sender Is red Then  
         Me.BackColor = Color.Red  
      Else  
         If sender Is blue Then  
            Me.BackColor = Color.Blue  
         Else  
            Me.BackColor = Color.Green  
         End If  
      End If   
   End Sub  
  
   ' The STAThreadAttribute informs the common language runtime that  
   ' Windows Forms uses the single-threaded apartment model.  
   <STAThread()> _  
   Public Shared Sub Main()  
      Application.Run(New MyForm())  
   End Sub  
End Class  
using System;  
using System.ComponentModel;  
using System.Windows.Forms;  
using System.Resources;  
using System.Drawing;  
  
public class MyForm : Form {  
   private Button red;  
   private Button blue;  
   private Button green;  
  
   public MyForm() : base() {     
      InitializeComponent();     
   }  
  
   protected override void Dispose(bool disposing) {  
      base.Dispose(disposing);  
   }  
  
// InitializeComponent is a helper method for the constructor.   
// It is included for consistency with code that is   
// auto-generated by the Windows Forms designer in Visual Studio.   
   private void InitializeComponent() {  
  
// A delegate for the click event of a button. The argument to   
// the constructor contains a reference to the method that performs the   
// event handling logic.  
      EventHandler handler = new EventHandler(button_Click);  
  
// Creates three buttons, sets their properties, and attaches  
// an event handler to each button.  
  
      red = new Button();  
      red.Text = "Red";  
      red.Location = new Point(100, 50);  
      red.Size = new Size(50, 50);  
      red.Click +=handler;  
      Controls.Add(red);  
  
      blue = new Button();  
      blue.Text = "Blue";  
      blue.Location = new Point(100, 100);  
      blue.Size = new Size(50, 50);  
      blue.Click += handler;  
      Controls.Add(blue);  
  
      green = new Button();  
      green.Text = "Green";  
      green.Location = new Point(100, 150);  
      green.Size = new Size(50, 50);  
      green.Click += handler;  
      Controls.Add(green);        
      }  
  
   // Event handler.  
   private void button_Click(object sender, EventArgs e) {  
            if (sender == red) this.BackColor = Color.Red ;  
                  else if (sender == blue) this.BackColor = Color.Blue;  
                  else this.BackColor = Color.Green;  
        }  
   // The STAThreadAttribute informs the common language runtime that  
   // Windows Forms uses the single-threaded apartment model.  
  [STAThread]  
   public static void Main(string[] args) {  
   Application.Run(new MyForm());  
   }  
  
}  

関連項目See also