Question

我有一个网格，我想移动鼠标。虽然我只是徘徊和移动鼠标我希望事件发生，但当我按下mousedown他们应该暂停开火。一旦我开火，他们就应该继续。

如果这听起来非常简单，那可能不是。过了一段时间我们提出了一个不太优雅的解决方案，但我想知道是否存在更好的东西。我不会用我们的黑客来影响你的方法。

所以初始代码不起作用

mouseMove.TakeUntil(mouseDown).Repeat()

向.SkipUntil(mouseUp)左侧或右侧添加TakeUntil基本上可以停止上述代码。

Answer 1

这个怎么样：

bool mouseIsDown = false;
Observable.Merge(
    mouseDown.Select(_ => true),
    mouseUp.Select(_ => false)
).Subscribe(x => mouseIsDown = x);

mouseMove.Where(_ => !mouseIsDown);

技术上正确的答案涉及Window操作符，但是这样很容易理解（并且我更容易编写）

Answer 2

这可能是一种可能的解决方案

// create the observables
IObservable<Point> mouseMove = Observable.FromEventPattern<MouseEventArgs>(this, "MouseDown")
    .Select(e=>e.EventArgs.GetPosition(this));

IObservable<bool> mouseDown = Observable.FromEventPattern(this, "MouseDown").Select(_ => false);
IObservable<bool> mouseUp = Observable.FromEventPattern(this, "MouseUp").Select(_ => true);

var merged = mouseUp.Merge(mouseDown).StartWith(true);

// sends the moves with the current state of the mouse button
var all = mouseMove.CombineLatest(merged, (move, take) => new {Take = take, Move = move});

// the result is all the points from mouse move where the mouse button isn't pressed
var result = all.Where(t => t.Take).Select(t => t.Move);

Answer 3

以下是2种可能的解决方案

var beh = new BehaviorSubject<bool>(true);
mousedown.Select(_ => false).Subscribe(beh);
mouseup.Select(_ => true).Subscribe(beh);
mousemove.SelectMany(e =>
{
     return mousemove.TakeUntil(beh.Where(b => !b));
}).Subscribe( .... );

或

var du = mousedown.Select(_ => false).Merge(mouseup.Select(_ => true)).Merge(Observable.Return(true)); mousemove.CombineLatest(du, (ev, b) => new Tuple<MouseEventArgs, bool>(ev.EventArgs, b)) .Where(t => t.Item2) .Select(t => t.Item1) .Subscribe(....);

Answer 4

这有效：

        var mouseMoveWhileUpOnly =
            mouseUp
                .Select(mu =>
                    mouseMove
                        .TakeUntil(mouseDown))
                .Switch();

在没有实际需要手动执行鼠标操作的情况下启动observable所需的唯一技巧是：

        var mouseUp = Observable
            .FromEventPattern<MouseButtonEventHandler, MouseButtonEventArgs>(
                h => this.MouseLeftButtonUp += h,
                h => this.MouseLeftButtonUp -= h)
            .Select(ep => Unit.Default)
            .StartWith(Unit.Default);

请注意StartWith。

否则mouseDown＆amp; mouseMove可观察量通常被定义。

如何在按下鼠标按钮时阻止鼠标移动事件？

4 个答案: