KeyEventHandler デリゲート

.NET Framework クラス ライブラリ リファレンス

KeyEventHandler デリゲート

Control の KeyUp イベントまたは KeyDown イベントを処理するメソッドを表します。

名前空間: System.Windows.Forms
アセンブリ: System.Windows.Forms (system.windows.forms.dll 内)
構文

Visual Basic (宣言)

Public Delegate Sub KeyEventHandler
 ( _
    sender As Object, _
    e As KeyEventArgs _
)

Visual Basic (使用法)

Dim instance As New KeyEventHandler(AddressOf
 HandlerMethod)

C#

public delegate void KeyEventHandler (
    Object sender,
    KeyEventArgs e
)

C++

public delegate void KeyEventHandler (
    Object^ sender, 
    KeyEventArgs^ e
)

J#

/** @delegate */
public delegate void KeyEventHandler (
    Object sender, 
    KeyEventArgs e
)

JScript

JScript では、デリゲートは使用できますが、新規に宣言することはできません。

パラメータ

sender

イベントのソース。

e

イベント データを格納している KeyEventArgs。

解説

KeyEventHandler デリゲートを作成する場合は、イベントを処理するメソッドを識別してください。イベントをイベント ハンドラに関連付けるには、デリゲートのインスタンスをイベントに追加します。デリゲートを削除しない限り、そのイベントが発生すると常にイベント ハンドラが呼び出されます。デリゲートを使用したイベント処理の詳細については、「イベントとデリゲート」を参照してください。

使用例

Visual Basic

Private Sub treeView1_KeyDown(sender As
 Object, _
  e As KeyEventArgs) Handles treeView1.KeyDown
   ' If the 'Alt' and 'E' keys are pressed,
   ' allow the user to edit the TreeNode label. 
   If e.Alt And e.KeyCode = Keys.E Then
      treeView1.LabelEdit = True
      ' If there is a TreeNode under the mose cursor, begin editing.
 
      Dim editNode As TreeNode = treeView1.GetNodeAt(
 _
        treeView1.PointToClient(Control.MousePosition))
      If Not (editNode Is
 Nothing) Then
         editNode.BeginEdit()
      End If
   End If
End Sub

Private Sub treeView1_AfterLabelEdit(sender
 As Object, _
  e As NodeLabelEditEventArgs) Handles treeView1.AfterLabelEdit
   ' Disable the ability to edit the TreeNode labels.
   treeView1.LabelEdit = False
End Sub

C#

private void treeView1_KeyDown(object sender,
 KeyEventArgs e)
{
   /* If the 'Alt' and 'E' keys are pressed,
      * allow the user to edit the TreeNode label. */
   if(e.Alt && e.KeyCode == Keys.E)
         
   {
      treeView1.LabelEdit = true;
      // If there is a TreeNode under the mose cursor, begin editing.
 
      TreeNode editNode = treeView1.GetNodeAt(
         treeView1.PointToClient(Control.MousePosition));
      if(editNode != null)
      { 
         editNode.BeginEdit();
      }
   }
}

private void treeView1_AfterLabelEdit(object
 sender, NodeLabelEditEventArgs e)
{
   // Disable the ability to edit the TreeNode labels.
   treeView1.LabelEdit = false;
}

C++

private:
   void treeView1_KeyDown( Object^ /*sender*/, KeyEventArgs^ e
 )
   {
      /* If the 'Alt' and 'E' keys are pressed,
         * allow the user to edit the TreeNode label. */
      if ( e->Alt && e->KeyCode == Keys::E )
      {
         treeView1->LabelEdit = true;
         
         // If there is a TreeNode under the mose cursor, begin editing.
         TreeNode^ editNode = treeView1->GetNodeAt( treeView1->PointToClient(
 Control::MousePosition ) );
         if ( editNode != nullptr )
         {
            editNode->BeginEdit();
         }
      }
   }

   void treeView1_AfterLabelEdit( Object^ /*sender*/, NodeLabelEditEventArgs^
 /*e*/ )
   {
      // Disable the ability to edit the TreeNode labels.
      treeView1->LabelEdit = false;
   }

J#

private void treeView1_KeyDown(Object sender,
 KeyEventArgs e)
{
    /* If the 'Alt' and 'E' keys are pressed,
       allow the user to edit the TreeNode label. 
     */
    if (e.get_Alt() && e.get_KeyCode() == Keys.E) {
        treeView1.set_LabelEdit(true);
        // If there is a TreeNode under the mose cursor, begin editing.
 
        TreeNode editNode = treeView1.GetNodeAt(treeView1.PointToClient(
            Control.get_MousePosition()));
        if (editNode != null) {
            editNode.BeginEdit();
        }
    }
} //treeView1_KeyDown

private void treeView1_AfterLabelEdit(Object
 sender, 
    NodeLabelEditEventArgs e)
{
    // Disable the ability to edit the TreeNode labels.
    treeView1.set_LabelEdit(false);
} //treeView1_AfterLabelEdit

Visual Basic

    ' Boolean flag used to determine when a character other than a number
 is entered.
    Private nonNumberEntered As Boolean
 = False
   
   
    ' Handle the KeyDown event to determine the type of character entered
 into the control.
    Private Sub textBox1_KeyDown(sender As
 Object, e As System.Windows.Forms.KeyEventArgs)
 _
         Handles textBox1.KeyDown
        ' Initialize the flag to false.
        nonNumberEntered = False
      
        ' Determine whether the keystroke is a number from the top of
 the keyboard.
        If e.KeyCode < Keys.D0 OrElse e.KeyCode
 > Keys.D9 Then
            ' Determine whether the keystroke is a number from the keypad.
            If e.KeyCode < Keys.NumPad0 OrElse
 e.KeyCode > Keys.NumPad9 Then
                ' Determine whether the keystroke is a backspace.
                If e.KeyCode <> Keys.Back Then
                    ' A non-numerical keystroke was pressed. 
                    ' Set the flag to true and evaluate in KeyPress
 event.
                    nonNumberEntered = True
                End If
            End If
        End If
    End Sub 'textBox1_KeyDown
   
   
    ' This event occurs after the KeyDown event and can be used 
    ' to prevent characters from entering the control.
    Private Sub textBox1_KeyPress(sender As
 Object, e As System.Windows.Forms.KeyPressEventArgs)
 _
        Handles textBox1.KeyPress
        ' Check for the flag being set in the KeyDown event.
        If nonNumberEntered = True Then
            ' Stop the character from being entered into the control
 since it is non-numerical.
            e.Handled = True
        End If
    End Sub 'textBox1_KeyPress
End Class 'Form1 

C#

// Boolean flag used to determine when a character other than a number
 is entered.
private bool nonNumberEntered = false;

// Handle the KeyDown event to determine the type of character entered
 into the control.
private void textBox1_KeyDown(object sender,
 System.Windows.Forms.KeyEventArgs e)
{
    // Initialize the flag to false.
    nonNumberEntered = false;

    // Determine whether the keystroke is a number from the top of the
 keyboard.
    if (e.KeyCode < Keys.D0 || e.KeyCode > Keys.D9)
    {
        // Determine whether the keystroke is a number from the keypad.
        if (e.KeyCode < Keys.NumPad0 || e.KeyCode > Keys.NumPad9)
        {
            // Determine whether the keystroke is a backspace.
            if(e.KeyCode != Keys.Back)
            {
                // A non-numerical keystroke was pressed.
                // Set the flag to true and evaluate in KeyPress event.
                nonNumberEntered = true;
            }
        }
    }
}

// This event occurs after the KeyDown event and can be used to prevent
// characters from entering the control.
private void textBox1_KeyPress(object sender,
 System.Windows.Forms.KeyPressEventArgs e)
{
    // Check for the flag being set in the KeyDown event.
    if (nonNumberEntered == true)
    {
        // Stop the character from being entered into the control since
 it is non-numerical.
        e.Handled = true;
    }
}

C++

   // Boolean flag used to determine when a character other than a number
 is entered.
private:
   bool nonNumberEntered;

   // Handle the KeyDown event to determine the type of character entered
 into the control.
   void textBox1_KeyDown( Object^ /*sender*/, System::Windows::Forms::KeyEventArgs^
 e )
   {
      // Initialize the flag to false.
      nonNumberEntered = false;

      // Determine whether the keystroke is a number from the top of the
 keyboard.
      if ( e->KeyCode < Keys::D0 || e->KeyCode > Keys::D9
 )
      {
         // Determine whether the keystroke is a number from the keypad.
         if ( e->KeyCode < Keys::NumPad0 || e->KeyCode
 > Keys::NumPad9 )
         {
            // Determine whether the keystroke is a backspace.
            if ( e->KeyCode != Keys::Back )
            {
               // A non-numerical keystroke was pressed.
               // Set the flag to true and evaluate in KeyPress event.
               nonNumberEntered = true;
            }
         }
      }
   }

   // This event occurs after the KeyDown event and can be used to prevent
   // characters from entering the control.
   void textBox1_KeyPress( Object^ /*sender*/, System::Windows::Forms::KeyPressEventArgs^
 e )
   {
      // Check for the flag being set in the KeyDown event.
      if ( nonNumberEntered == true )
      {         // Stop the character from being entered into the control since
 it is non-numerical.
         e->Handled = true;
      }
   }

J#

// Boolean flag used to determine when a character other than a number
 
// is entered.
private boolean nonNumberEntered = false;

// Handle the KeyDown event to determine the type of character entered
 
// into the control.
private void textBox1_KeyDown(Object sender,
 
    System.Windows.Forms.KeyEventArgs e)
{
    // Initialize the flag to false.
    nonNumberEntered = false;

    // Determine whether the keystroke is a number from the top of the
 
    // keyboard.
    if ((e.get_KeyCode().CompareTo(Keys.D0)) < 0 
        || (e.get_KeyCode().CompareTo(Keys.D9) > 0)) {

        // Determine whether the keystroke is a number from the keypad.
        if ((e.get_KeyCode().CompareTo(Keys.NumPad0) < 0 
            || (e.get_KeyCode().CompareTo(Keys.NumPad9)) > 0)) {

            // Determine whether the keystroke is a backspace.
            if (!(e.get_KeyCode().Equals(Keys.Back))) {
                    // A non-numerical keystroke was pressed.
                    // Set the flag to true and evaluate in KeyPress
 event.
                    nonNumberEntered = true;
            }
        }
    }
} //textBox1_KeyDown

// This event occurs after the KeyDown event and can be used to prevent
// characters from entering the control.
private void textBox1_KeyPress(Object sender,
 System.Windows.Forms.
    KeyPressEventArgs e)
{
    // Check for the flag being set in the KeyDown event.
    if (nonNumberEntered == true) {
        // Stop the character from being entered into the control since
 
        // it is non-numerical.
        e.set_Handled(true);
    }
} //textBox1_KeyPress

プラットフォーム

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。

バージョン情報

.NET Framework
サポート対象 : 2.0、1.1、1.0
.NET Compact Framework
サポート対象 : 2.0、1.0

参照

関連項目
System.Windows.Forms 名前空間
OnKeyUp
Control.KeyUp イベント
OnKeyDown
Control.KeyDown イベント
KeyEventArgs クラス
OnKeyPress
Control.KeyPress イベント
KeyPressEventArgs