Control.KeyUp Evento
Definizione
Importante
Alcune informazioni sono relative alla release non definitiva del prodotto, che potrebbe subire modifiche significative prima della release definitiva. Microsoft non riconosce alcuna garanzia, espressa o implicita, in merito alle informazioni qui fornite.
Si verifica quando si rilascia un tasto mentre il controllo ha lo stato attivo.
public:
event System::Windows::Forms::KeyEventHandler ^ KeyUp;public event System.Windows.Forms.KeyEventHandler KeyUp;public event System.Windows.Forms.KeyEventHandler? KeyUp;member this.KeyUp : System.Windows.Forms.KeyEventHandler Public Custom Event KeyUp As KeyEventHandler Tipo evento
Esempio
Nell'esempio di codice seguente viene usato l'evento KeyUp con la Help classe per visualizzare la Guida popup all'utente.
// This example demonstrates how to use the KeyUp event with the Help class to display
// pop-up style help to the user of the application. When the user presses F1, the Help
// class displays a pop-up window, similar to a ToolTip, near the control. This example assumes
// that a TextBox control, named textBox1, has been added to the form and its KeyUp
// event has been connected to this event handler method.
private:
void textBox1_KeyUp( Object^ /*sender*/, System::Windows::Forms::KeyEventArgs^ e )
{
// Determine whether the key entered is the F1 key. Display help if it is.
if ( e->KeyCode == Keys::F1 )
{
// Display a pop-up help topic to assist the user.
Help::ShowPopup( textBox1, "Enter your first name", Point(textBox1->Right,this->textBox1->Bottom) );
}
}
// This example demonstrates how to use the KeyUp event with the Help class to display
// pop-up style help to the user of the application. When the user presses F1, the Help
// class displays a pop-up window, similar to a ToolTip, near the control. This example assumes
// that a TextBox control, named textBox1, has been added to the form and its KeyUp
// event has been contected to this event handler method.
private void textBox1_KeyUp(object sender, System.Windows.Forms.KeyEventArgs e)
{
// Determine whether the key entered is the F1 key. Display help if it is.
if(e.KeyCode == Keys.F1)
{
// Display a pop-up help topic to assist the user.
Help.ShowPopup(textBox1, "Enter your first name", new Point(textBox1.Right, this.textBox1.Bottom));
}
}
' This example demonstrates how to use the KeyUp event with the Help class to display
' pop-up style help to the user of the application. When the user presses F1, the Help
' class displays a pop-up window, similar to a ToolTip, near the control. This example assumes
' that a TextBox control, named textBox1, has been added to the form and its KeyUp
' event has been contected to this event handler method.
Private Sub textBox1_KeyUp(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles textBox1.KeyUp
' Determine whether the key entered is the F1 key. Display help if it is.
If e.KeyCode = Keys.F1 Then
' Display a pop-up help topic to assist the user.
Help.ShowPopup(textBox1, "Enter your first name", New Point(textBox1.Right, Me.textBox1.Bottom))
End If
End Sub
Nell'esempio di codice seguente viene illustrato l'ordine di aumento KeyDowndegli eventi e KeyUpKeyPress , nonché come registrare i gestori eventi su di essi.
public partial class Form2 : Form
{
public Form2()
{
InitializeComponent();
textBox2.Multiline = true;
textBox2.ScrollBars = ScrollBars.Both;
//Setup events that listens on keypress
textBox1.KeyDown += TextBox1_KeyDown;
textBox1.KeyPress += TextBox1_KeyPress;
textBox1.KeyUp += TextBox1_KeyUp;
}
// Handle the KeyUp event to print the type of character entered into the control.
private void TextBox1_KeyUp(object sender, KeyEventArgs e)
{
textBox2.AppendText( $"KeyUp code: {e.KeyCode}, value: {e.KeyValue}, modifiers: {e.Modifiers}" + "\r\n");
}
// Handle the KeyPress event to print the type of character entered into the control.
private void TextBox1_KeyPress(object sender, KeyPressEventArgs e)
{
textBox2.AppendText( $"KeyPress keychar: {e.KeyChar}" + "\r\n");
}
// Handle the KeyDown event to print the type of character entered into the control.
private void TextBox1_KeyDown(object sender, KeyEventArgs e)
{
textBox2.AppendText( $"KeyDown code: {e.KeyCode}, value: {e.KeyValue}, modifiers: {e.Modifiers}" + "\r\n");
}
}
Public Class Form2
' Handle the KeyDown event to print the type of character entered into the control.
Private Sub TextBox1_KeyDown(sender As Object, e As KeyEventArgs) Handles TextBox1.KeyDown
TextBox2.AppendText($"KeyDown code: {e.KeyCode}, value: {e.KeyValue}, modifiers: {e.Modifiers}" + vbCrLf)
End Sub
' Handle the KeyPress event to print the type of character entered into the control.
Private Sub TextBox1_KeyPress(sender As Object, e As KeyPressEventArgs) Handles TextBox1.KeyPress
TextBox2.AppendText($"KeyPress keychar: {e.KeyChar}" + vbCrLf)
End Sub
' Handle the KeyUp event to print the type of character entered into the control.
Private Sub TextBox1_KeyUp(sender As Object, e As KeyEventArgs) Handles TextBox1.KeyUp
TextBox2.AppendText($"KeyUp code: {e.KeyCode}, value: {e.KeyValue}, modifiers: {e.Modifiers}" + vbCrLf)
End Sub
End Class
Commenti
Gli eventi chiave si verificano nell'ordine seguente:
Per gestire gli eventi della tastiera solo a livello di modulo e non consentire ad altri controlli di ricevere gli eventi della tastiera, impostare la KeyPressEventArgs.Handled proprietà nel metodo di gestione degli eventi del KeyPress modulo su true. Alcuni tasti, ad esempio TAB, RETURN, ESC e freccia, vengono gestiti automaticamente dai controlli . Per fare in modo che queste chiavi generino l'evento, è necessario eseguire l'override KeyUp del IsInputKey metodo in ogni controllo del modulo. Il codice per l'override di IsInputKey deve determinare se uno dei tasti speciali viene premuto e restituisce un valore di true.
Per ulteriori informazioni sulla gestione degli eventi, consultare gestione e generazione di eventi.
