C# 为什么我的控件在 KeyDown 事件中不接受多个键

Question

Ok guys so I've been working on this control for close to a month and one of the issues that I'm having is that if I press the CTRL key by it's self it registers and if I press the Space key by it's self it registers. I've tried to separate the two and I've tried to use them in the same if statement. Both are unsuccessful.

My first attempt was like this

protected override void OnKeyDown(KeyEventArgs e)
    {
        // base.OnKeyDown(e);
        if (_isEditing)
        {
            if (e.KeyData == Keys.Delete)
            {
                if (_selectedObj != null)
                {
                    DeleteSelectedObject();
                }
            }
        }
        if (e.Control && e.KeyData == Keys.Space)
        {
            _isEditing = !_isEditing;
            Invalidate();
        }
    }

Now if I remove the Ctrl or the 'Space' key from the equation it works fine. So I tried to separate them and came up with

protected override void OnKeyDown(KeyEventArgs e)
    {
        // base.OnKeyDown(e);
        if (_isEditing)
        {
            if (e.KeyData == Keys.Delete)
            {
                if (_selectedObj != null)
                {
                    DeleteSelectedObject();
                }
            }
        }
        if (e.Control)
        {
            Console.WriteLine(DateTime.Now.ToShortTimeString());
            if (e.KeyData.Equals(Keys.Space))
            {
                _isEditing = !_isEditing;
                Console.WriteLine(DateTime.Now.Ticks.ToString());
            }
            Invalidate();
        }
    }

using the Console.WriteLine() as a cheater to tell me when the key is pressed and the Ticks doesn't get displayed unless I Comment out the CTRL clause. Where am I going wrong here?

Answer 1

Try something like

if (e.Modifiers == Keys.Control && e.KeyCode == Keys.Space)
{

}

Answer 2

You won't get modifier in a KeyDown event. Rather try one of the following ways to know if modifiers (Ctrl, Shift, Alt) are pressed or not:

1. Keyboard.IsKeyDown

    if ((Keyboard.IsKeyDown(Key.LeftShift) || Keyboard.IsKeyDown(Key.RightShift)) && e.KeyData == Keys.Space){}

2. Check Keyboard.Modifiers

    if ((Keyboard.Modifiers & ModifierKeys.Control) == ModifierKeys.Control) && e.KeyData == Keys.Space){}