贪食蛇求助！！！
现在场地和蛇都已经做好了，蛇也能动，就是键盘怎么按都没用，下面是代码，求大神解答~~~~~~~
private void Start_KeyDown(object sender,KeyEventArgs e)
{
int pressKeyValue;
int direction = myFloor.CurrentSnake.Direction;
pressKeyValue = e.KeyValue;
if (pressKeyValue == 37)
direction = 3;
else if (pressKeyValue == 38)
direction = 0;
else if (pressKeyValue == 39)
direction = 1;
else if (pressKeyValue == 40)
direction = 2;
myFloor.CurrentSnake.TurnDirection(direction);
}