Keys Enumeración

Definición

public enum class Keys

[System.ComponentModel.TypeConverter(typeof(System.Windows.Forms.KeysConverter))]
[System.Flags]
[System.Runtime.InteropServices.ComVisible(true)]
public enum Keys

[System.ComponentModel.TypeConverter(typeof(System.Windows.Forms.KeysConverter))]
[System.Flags]
public enum Keys

[<System.ComponentModel.TypeConverter(typeof(System.Windows.Forms.KeysConverter))>]
[<System.Flags>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type Keys = 

[<System.ComponentModel.TypeConverter(typeof(System.Windows.Forms.KeysConverter))>]
[<System.Flags>]
type Keys = 

Public Enum Keys

Herencia

Object

ValueType

Enum

Keys

Atributos

TypeConverterAttribute FlagsAttribute ComVisibleAttribute

Campos

Ejemplos

En el ejemplo de código siguiente se usa el KeyDown evento para determinar el tipo de carácter especificado en el control .

   // 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

Comentarios

La Keys clase contiene constantes para procesar la entrada del teclado. Los miembros de la enumeración Keys constan de un código de clave y un conjunto de modificadores combinados en un único valor entero. En la interfaz de programación de aplicaciones (API) win32, un valor de clave tiene dos mitades, con los bits de orden superior que contienen el código de clave (que es el mismo que un código de clave virtual de Windows) y los bits de orden bajo que representan modificadores de clave como las teclas MAYÚS, CONTROL y ALT.

• Llame al método IsKeyLocked de la clase Control .

• Para un control más preciso, use las funciones GetKeyStatede la API de Windows , GetAsyncKeyStateo GetKeyboardState definidas en user32.dll, para ello. Para obtener más información sobre cómo llamar a funciones nativas, consulte Consumo de funciones DLL no administradas.

En la tabla siguiente se muestran los valores de código clave representados por dos valores enumerados, que representan las teclas generales del fabricante de equipos originales (OEM) y las asociaciones de teclado más específicas de EE. UU.

Se aplica a

Consulte también

• KeysConverter
• SendKeys
• ConsoleKey
• Shortcut
• ModifierKeys
• IsKeyLocked(Keys)
• KeyEventArgs