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KeyEventArgs Classe

Fornece dados para o evento KeyDown ou KeyUp.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (em System.Windows.Forms. dll)

[ComVisibleAttribute(true)]
public class KeyEventArgs : EventArgs

A KeyEventArgs, which specifies the key the user pressed and whether any modifier keys (CTRL, ALT, and SHIFT) were pressed at the same time, is passed with each KeyDown or KeyUp event.

The KeyDown event occurs when the user presses any key.The KeyUp event occurs when the user releases the key.Duplicate KeyDown events occur each time the key repeats, if the key is held down, but only one KeyUp event is generated when the user releases the key.

The KeyPress event also occurs when a key is pressed.A KeyPressEventArgs is passed with each KeyPress event, and specifies the character that was composed as a result of each key press.

For information about the event model, see Eventos e representantes.

Os exemplos de código a seguir demonstram como detectar o estado de um Pressionarionar de tecla.

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.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 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.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 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 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


System.Object
  System.EventArgs
    System.Windows.Forms.KeyEventArgs

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