c# winforms -查找在LostFocus事件中关注的控件

我正在开发一个应用程序，可以在标准pc和触摸屏pc上运行。该应用程序有许多用于数值的输入框。因此，我在GIU中添加了一个数字键盘。

我使用下面的代码将键盘链接到选定的文本框，这工作得相对较好。然而，应用程序有几个选项卡部分，我想设置这一点。如果焦点被不属于键盘或数值输入框集的任何其他控件占用，则将currentControlWithFocus设置为null。这将有助于避免偶然的键盘按下，这将导致更新由currentControlWithFocus引用的最后一个数字输入框。

我也愿意接受任何关于实现屏幕键盘的更好方法的建议。

    /// <summary>
    /// Store current control that has focus.
    /// This object will be used by the keypad to determin which textbox to update.
    /// </summary>
    private Control currentControlWithFocus = null;
    private void EventHandler_GotFocus(object sender, EventArgs e)
    {
        ((TextBox)sender).BackColor = Color.Yellow;
        this.currentControlWithFocus = (Control)sender;
    }
    private void EventHandler_LostFocus(object sender, EventArgs e)
    {
        ((TextBox)sender).BackColor = Color.White;
    }
    /// <summary>
    /// Append button's text which represent a number ranging between 0 and 9
    /// </summary>
    private void buttonKeypad_Click(object sender, EventArgs e)
    {
        if (this.currentControlWithFocus != null)
        {
            this.currentControlWithFocus.Text += ((Button)sender).Text;
            this.currentControlWithFocus.Focus();
        }
    }
    /// <summary>
    /// Removes last char from a textbox
    /// </summary>
    private void buttonKeypad_bckspc_Click(object sender, EventArgs e)
    {
        if (this.currentControlWithFocus != null)
        {
            string text = this.currentControlWithFocus.Text;
            // remove last char if the text is not empty
            if (text.Length > 0)
            {
                text = text.Remove(text.Length - 1);
                this.currentControlWithFocus.Text = text;
            }
            this.currentControlWithFocus.Focus();
        }
    }

EventHandler_LostFocus和EventHandler_GotFocus被添加到大约20个左右的输入框。buttonKeypad_Click被添加到表示数字从0到9和的10个按钮中buttonKeypad_bckspc_Click被添加到退格按钮

如果我能确定哪个控件把焦点从输入框上移开了，我就喜欢这样做。

    private void EventHandler_LostFocus(object sender, EventArgs e)
    {
        // IF NEW CONTROL WITH FOCUS IS NOT ONE OF KEYPAD BUTTONS
        //   THEN 
              ((TextBox)sender).BackColor = Color.White;
              this.currentControlWithFocus = null;
    }

public static Control FindFocusedControl(Control control)
{
    var container = control as ContainerControl;
    while (container != null)
    {
        control = container.ActiveControl;
        container = control as ContainerControl;
    }
    return control;
}