async void DispatchKeyEvent()
{
var map = _seaMapInfo.MapFrame;
var movePoints = new Dictionary <Key, Point>();
movePoints[Key.Left] = new Point(1, 0);
movePoints[Key.Right] = new Point(-1, 0);
movePoints[Key.Up] = new Point(0, 1);
movePoints[Key.Down] = new Point(0, -1);
var directionKeyDown = from i in Observable.FromEventPattern <KeyEventArgs>(map, "KeyDown")
let key = i.EventArgs.Key
where movePoints.ContainsKey(key)
select movePoints[key];
while (true)
{
var p = await directionKeyDown.FirstAsync();
var dx = p.X;
var dy = p.Y;
bool isShiftKeyDown = Keyboard.IsKeyDown(Key.LeftShift) || Keyboard.IsKeyDown(Key.RightShift);
if (isShiftKeyDown)
{
dx *= map.ActualWidth / 25;
dy *= map.ActualHeight / 25;
}
else
{
dx *= map.ActualWidth / 4;
dy *= map.ActualHeight / 4;
}
await _locator.Offset(dx, dy);
//防止方向键移动焦点到其它控件上
map.Focus();
}
}