private void mainGrid_PreviewMouseUp(object sender, MouseButtonEventArgs e)
{
// is this the end of a drag operation?
if (this.dragTumbler != null)
{
double offset = -Canvas.GetTop(this.dragTumbler);
Point mousePt = Mouse.GetPosition(this.mainGrid);
if (mousePt.Equals(this.dragPt))
{
// user clicked on tumbler without dragging, select the clicked-on value
offset += mousePt.Y - (this.mainGrid.ActualHeight / 2);
}
// find the Canvas offset for the value closest to where the drag ended
TumblerData td = this.dragTumbler.Tag as TumblerData;
double itemHeight = this.dragTumbler.ActualHeight / (td.Values.Count);
double newVal = offset / itemHeight + 2;
int iVal = (int)Math.Round(newVal);
// update index, limit to valid values. The update will cause NotifyPropertyChanged which
// will animate the tumbler into the appropriate position for the selected value
td.SelectedValueIndex = Math.Min(Math.Max(0, iVal), td.Values.Count - 1);
this.dragTumbler = null;
}
if (this.mainGrid.IsMouseCaptured && this.AlwaysOpen)
{
this.mainGrid.ReleaseMouseCapture();
}
}
public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
TumblerData td = values[0] as TumblerData;
bool isOpen = (bool)values[1];
int currentIndex = (int)values[2];
return(isOpen || (td != null && currentIndex == td.SelectedValueIndex) ? Visibility.Visible : Visibility.Hidden);
}
/// <summary>
/// Mouse wheel handler for tumblers. This is not a fired event because we need to mouse capture on the main grid
/// so we can know when to close the control. Instead this event gets called via the MouseWheel event on the main grid.
/// </summary>
/// <param name="tumbler">The tumbler (grid) that should receive the mouse wheel event</param>
/// <param name="e">the MouseWheelEventArgs forwarded from the main grid MouseWheel event</param>
private void Tumbler_PreviewMouseWheel(Grid tumbler, MouseWheelEventArgs e)
{
if (tumbler != null)
{
TumblerData td = tumbler.Tag as TumblerData;
// Each click in the mouse will increment or decrement the tumbler value by one
int newIdx = td.SelectedValueIndex + (e.Delta > 0 ? -1 : 1);
if (newIdx >= 0 && newIdx < td.Values.Count)
{
// Set the new index which will cause NotifyPropertyChanged to fire, which in turn will cause
// the binding/converter to re-evaluate, which will result in the tumbler animating to the correct
// canvas offset.
td.SelectedValueIndex = newIdx;
}
}
}
public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
// TumblerDataToOffsetConverter is just a shell for getting SelectedValueChanged event and using it to adjust the items grid
// canvas offset. Reason we don't just bind the Canvas.Top property directly is because that binding will
// get lost when we manually set Canvas.Top via drag support
Grid tumbler = values[0] as Grid;
TumblerData td = tumbler.Tag as TumblerData;
if (td != null)
{
double itemHeight = tumbler.ActualHeight / (td.Values.Count);
double offset = td.SelectedValueIndex > 0 ? -(td.SelectedValueIndex - 2) * itemHeight : itemHeight * 2;
// animate from current position to value offset
DoubleAnimation da = new DoubleAnimation();
da.From = Canvas.GetTop(tumbler);
da.To = offset;
da.Duration = new Duration(TimeSpan.FromMilliseconds(100));
tumbler.BeginAnimation(Canvas.TopProperty, da);
}
return(values[2]);
}
