KeyEventArgs-Klasse
Stellt Daten für das KeyDown-Ereignis oder das KeyUp-Ereignis bereit.
Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in system.windows.forms.dll)
Syntax
'Declaration
<ComVisibleAttribute(True)> _
Public Class KeyEventArgs
Inherits EventArgs
'Usage
Dim instance As KeyEventArgs
[ComVisibleAttribute(true)]
public class KeyEventArgs : EventArgs
[ComVisibleAttribute(true)]
public ref class KeyEventArgs : public EventArgs
/** @attribute ComVisibleAttribute(true) */
public class KeyEventArgs extends EventArgs
ComVisibleAttribute(true)
public class KeyEventArgs extends EventArgs
Hinweise
Bei jedem KeyDown-Ereignis oder KeyUp-Ereignis wird eine Instanz von KeyEventArgs übergeben, die die vom Benutzer gedrückte Taste und ggf. Informationen zu gleichzeitig gedrückten Modifizierertasten (STRG, ALT oder UMSCHALTTASTE) enthält.
Das KeyDown-Ereignis tritt ein, wenn der Benutzer eine beliebige Taste drückt. Das KeyUp-Ereignis tritt ein, sobald der Benutzer die Taste loslässt. Wenn der Benutzer die Taste gedrückt hält, wird für jede Wiederholung der Taste ein weiteres KeyDown-Ereignis ausgelöst. Das KeyUp-Ereignis wird jedoch nur einmal ausgelöst, wenn der Benutzer die Taste loslässt.
Das KeyPress-Ereignis tritt auch ein, wenn eine Taste gedrückt wird. Mit jedem KeyPress-Ereignis wird eine Instanz von KeyPressEventArgs übergeben, die das aus dem Tastendruck resultierende Zeichen angibt.
Informationen zum Ereignismodell finden Sie unter Ereignisse und Delegaten.
Beispiel
In den folgenden Codebeispielen wird veranschaulicht, wie der Zustand eines Tastendrucks ermittelt wird.
' 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-handler 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 TextBox control, named textBox1, has been added to the form and its KeyDown
' event has been contected to this event-handler method.
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 'textBox1_KeyDown
// 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-handler 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-handler 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.", 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));
}
}
// 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) );
}
}
// 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.get_KeyCode().Equals(Keys.F1) && (e.get_Alt() || e.get_Control()
|| e.get_Shift())) {
// Display a pop-up Help topic to assist the user.
Help.ShowPopup(textBox1, "Enter your name.", new Point(textBox1.
get_Bottom(), textBox1.get_Right()));
}
else {
if (e.get_KeyCode().Equals(Keys.F2) && e.get_Modifiers().
Equals(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.get_Top(), this.textBox1.get_Left()));
}
}
} //textBox1_KeyDown
} //Form1
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
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;
}
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;
}
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
' 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
// 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;
}
}
// 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;
}
}
// 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
Vererbungshierarchie
System.Object
System.EventArgs
System.Windows.Forms.KeyEventArgs
Threadsicherheit
Alle öffentlichen statischen (Shared in Visual Basic) Member dieses Typs sind threadsicher. Bei Instanzmembern ist die Threadsicherheit nicht gewährleistet.
Plattformen
Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile für Pocket PC, Windows Mobile für Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.
Versionsinformationen
.NET Framework
Unterstützt in: 2.0, 1.1, 1.0
.NET Compact Framework
Unterstützt in: 2.0, 1.0
Siehe auch
Referenz
KeyEventArgs-Member
System.Windows.Forms-Namespace
OnKeyDown
Control.KeyDown-Ereignis
OnKeyUp
Control.KeyUp-Ereignis
KeyPressEventArgs
OnKeyPress
Control.KeyPress-Ereignis