KeyEventArgs Classe

Définition

public ref class KeyEventArgs : EventArgs

[System.Runtime.InteropServices.ComVisible(true)]
public class KeyEventArgs : EventArgs

public class KeyEventArgs : EventArgs

[<System.Runtime.InteropServices.ComVisible(true)>]
type KeyEventArgs = class
    inherit EventArgs

type KeyEventArgs = class
    inherit EventArgs

Public Class KeyEventArgs
Inherits EventArgs

Héritage

Object

EventArgs

KeyEventArgs

Attributs

ComVisibleAttribute

Exemples

Les exemples de code suivants montrent comment détecter l’état d’un appui sur une touche.

Exemple 1

L’exemple de code suivant montre comment utiliser l’événement KeyDown avec la Help classe pour afficher le style pop-up Help à l’utilisateur de l’application. L’exemple utilise les KeyEventArgs propriétés passées à la méthode de gestionnaire d’événements pour filtrer toutes les variantes d’appui sur la touche F1 avec une touche modificateur. Lorsque l’utilisateur appuie sur une variante de F1 qui inclut un modificateur de clavier, la Help classe affiche une fenêtre contextuelle, similaire à un ToolTip, près du contrôle. Si l’utilisateur appuie sur ALT+F2, une autre fenêtre contextuelle d’aide s’affiche avec des informations supplémentaires.

   // This example demonstrates how to use the KeyDown event with the Help class to display
   // pop-up style help to the user of the application. The example filters for all variations
   // of pressing the F1 key with a modifier key by using the KeyEventArgs properties passed
   // to the event handling method.
   // When the user presses any variation of F1 that includes any keyboard modifier, the Help
   // class displays a pop-up window, similar to a ToolTip, near the control. If the user presses
   // ALT + F2, a different Help pop-up is displayed with additional information. This example assumes
   // that a tTextBox control, named textBox1, has been added to the form and its KeyDown
   // event has been contected to this event handling method.
private:
   void textBox1_KeyDown( Object^ /*sender*/, System::Windows::Forms::KeyEventArgs^ e )
   {
      // Determine whether the key entered is the F1 key. If it is, display Help.
      if ( e->KeyCode == Keys::F1 && (e->Alt || e->Control || e->Shift) )
      {
         
         // Display a pop-up Help topic to assist the user.
         Help::ShowPopup( textBox1, "Enter your name.", Point(textBox1->Bottom,textBox1->Right) );
      }
      else
      if ( e->KeyCode == Keys::F2 && e->Modifiers == Keys::Alt )
      {
         // Display a pop-up Help topic to provide additional assistance to the user.
         Help::ShowPopup( textBox1, "Enter your first name followed by your last name. Middle name is optional.",
            Point(textBox1->Top,this->textBox1->Left) );
      }
   }

private void textBox1_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
    // Determine whether the key entered is the F1 key. If it is, display Help.
    if(e.KeyCode == Keys.F1 && (e.Alt || e.Control || e.Shift))
    {
        // Display a pop-up Help topic to assist the user.
        Help.ShowPopup(textBox1, "Enter your name.", new Point(textBox1.Bottom, textBox1.Right));
    }
    else if(e.KeyCode == Keys.F2 && e.Modifiers == Keys.Alt)
    {
        // Display a pop-up Help topic to provide additional assistance to the user.
        Help.ShowPopup(textBox1, "Enter your first name followed by your last name. Middle name is optional.",
            new Point(textBox1.Top, this.textBox1.Left));
    }
}

Private Sub textBox1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles textBox1.KeyDown
    ' Determine whether the key entered is the F1 key. If it is, display Help.
    If e.KeyCode = Keys.F1 AndAlso (e.Alt OrElse e.Control OrElse e.Shift) Then
        ' Display a pop-up Help topic to assist the user.
        Help.ShowPopup(textBox1, "Enter your name.", New Point(textBox1.Bottom, textBox1.Right))
    ElseIf e.KeyCode = Keys.F2 AndAlso e.Modifiers = Keys.Alt Then
        ' Display a pop-up Help topic to provide additional assistance to the user.
        Help.ShowPopup(textBox1, "Enter your first name followed by your last name. Middle name is optional.", _
             New Point(textBox1.Top, Me.textBox1.Left))
    End If
End Sub

Exemple 2

L’exemple suivant détermine si l’utilisateur a appuyé sur ALT+E et si le pointeur de la souris se trouve sur un TreeNode, permet à l’utilisateur de modifier ce .TreeNode

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 mouse 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;
   }

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 mouse cursor, begin editing. 
      TreeNode editNode = treeView1.GetNodeAt(
         treeView1.PointToClient(System.Windows.Forms.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;
}

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 mouse cursor, begin editing. 
      Dim editNode As TreeNode = treeView1.GetNodeAt( _
        treeView1.PointToClient(System.Windows.Forms.Control.MousePosition))
      If (editNode IsNot 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

Exemple 3

L’exemple suivant détermine si l’utilisateur a appuyé sur une touche non numérique et, le cas échéant, annule l’événement à l’aide KeyPress de la Handled propriété .

   // 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;
            }
         }
      }
      //If shift key was pressed, it's not a number.
      if (Control::ModifierKeys == Keys::Shift) {
         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;
      }
   }

// 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;
            }
        }
    }
    //If shift key was pressed, it's not a number.
    if (Control.ModifierKeys == Keys.Shift) {
        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;
    }
}

 ' 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
     'If shift key was pressed, it's not a number.
     If Control.ModifierKeys = Keys.Shift Then
         nonNumberEntered = true
     End If
 End Sub


 ' 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

Remarques

, KeyEventArgsqui spécifie la touche enfoncée par l’utilisateur et si des touches de modificateur (Ctrl, Alt et Maj) ont été enfoncées en même temps, est passé avec chaque KeyDown événement ou KeyUp .

L’événement KeyDown se produit lorsque l’utilisateur appuie sur une touche. L’événement KeyUp se produit lorsque l’utilisateur libère la clé. Des événements dupliqués KeyDown se produisent chaque fois que la clé se répète, si la clé est arrêtée, mais qu’un KeyUp seul événement est généré lorsque l’utilisateur libère la clé.

L’événement KeyPress se produit également lorsqu’une touche est enfoncée. Un KeyPressEventArgs est passé avec chaque KeyPress événement et spécifie le caractère qui a été composé à la suite de chaque appui sur la touche.

Pour plus d’informations sur le modèle d’événement, consultez Gestion et déclenchement d’événements.

Constructeurs

Propriétés

Méthodes

S’applique à

Voir aussi

• OnKeyDown(KeyEventArgs)
• KeyDown
• OnKeyUp(KeyEventArgs)
• KeyUp
• KeyPressEventArgs
• OnKeyPress(KeyPressEventArgs)
• KeyPress