c# - WPF MouseButtonEventArgs Timestamp 值为负数？

Question

我有一些用于检查双击的 WPF 触发器的代码:

private void HandleButtonUp(object sender, MouseButtonEventArgs mouseEventArgs)
    {
        if (mouseEventArgs.ChangedButton == MouseButton.Left &&
            (mouseEventArgs.Timestamp - _lastClick) < SystemInfo.DoubleClickTime)
        {
            this.InvokeActions(mouseEventArgs);
            _lastClick = 0; // Require 2 clicks again
        }
        else 
            _lastClick = mouseEventArgs.Timestamp;
    }

到目前为止，这一直运作良好。但是今天，突然单击一下就会调用该操作。当我检查代码时，我发现时间戳值是负，这导致它总是小于 SystemInfo.DoubleClickTime(我设置的是 500)。

这正常吗？怎么突然变了？

Answer 1

InputEventArgs.Timestamp 属性的行为类似于 Environment.TickCount ，您可以在其中找到以下备注:

The value of this property is derived from the system timer and is stored as a 32-bit signed integer. Consequently, if the system runs continuously, TickCount will increment from zero to Int32.MaxValue for approximately 24.9 days, then jump to Int32.MinValue, which is a negative number, then increment back to zero during the next 24.9 days.

TickCount is different from the Ticks property, which is the number of 100-nanosecond intervals that have elapsed since 1/1/0001, 12:00am.

Use the DateTime.Now property to obtain the current local date and time on this computer.

忽略跳跃发生的罕见情况(24.9 天后，然后每 49.7 天)，您可以这样检查:

Math.Abs(mouseEventArgs.Timestamp - _lastClick) < SystemInfo.DoubleClickTime