Control.KeyUp 事件

定義

命名空間:

System.Windows.Forms

組件:

System.Windows.Forms.dll

來源:

Control.cs

發生於放開按鍵且焦點在控制項時。

C#

public event System.Windows.Forms.KeyEventHandler? KeyUp;

事件類型

KeyEventHandler

範例

下列程式碼範例會 KeyUp 使用 事件搭配 Help 類別，向使用者顯示快顯樣式說明。

C#

// 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));
    }
}

下列程式碼範例示範引發 KeyDown 、 KeyUp 和 KeyPress 事件的順序，以及如何在它們上註冊事件處理常式。

C#

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");
    }
}

備註

主要事件會依下列順序發生：

1. KeyDown

2. KeyPress

3. KeyUp

若要只在表單層級處理鍵盤事件，而且不會讓其他控制項接收鍵盤事件，請將 KeyPressEventArgs.Handled 表單的事件處理常式方法中的 KeyPress 屬性設定為 true 。 控制項會自動處理某些索引鍵，例如 TAB、RETURN、ESC 和方向鍵。 若要讓這些索引鍵引發 KeyUp 事件，您必須覆寫 IsInputKey 表單上每個控制項中的 方法。 覆寫 IsInputKey 的程式碼必須判斷是否按下其中一個特殊按鍵，並傳回 的值 true 。

如需處理事件的詳細資訊，請參閱 處理和引發事件。

適用於

另請參閱

• OnKeyUp(KeyEventArgs)
• KeyDown
• KeyPress