C#：object.ShortcutKeys 不支持非功能单独按键

崩溃

MenuItem.ShortcutKeys = Keys.D1;

正常

MenuItem.ShortcutKeys = Keys.F5;
MenuItem.ShortcutKeys = Keys.Ctrl | Keys.D1;

单独按键修改

public Form1() {
    this.KeyDown += Form1_KeyDown;
}

void Form1_KeyDown(object sender, KeyEventArgs e) {
    if (e.KeyCode == Keys.D1 || e.KeyCode == Keys.NumPad1) {
	    ......
	} 
}