private void OnScrollBarValueChanged(System.Windows.Controls.Primitives.ScrollBar scrollBar, ScrollBarParameter parameter)
{
if (scrollBar != null)
{
double oldThumbLength = scrollBar.GetThumbLength();
double oldThumbCenter = scrollBar.GetThumbCenter();
double newThumbLength = parameter.EndValue - parameter.StartValue;
double newThumbCenter = (parameter.StartValue + parameter.EndValue) / 2;
bool newEnabled = (parameter.StartValue > 0 || parameter.EndValue < 1);
double newMaximuum = newEnabled ? 1 : 0;
if (oldThumbLength != newThumbLength ||
oldThumbCenter != newThumbCenter ||
scrollBar.SmallChange != parameter.SmallChange ||
scrollBar.LargeChange != parameter.LargeChange ||
scrollBar.IsEnabled != newEnabled ||
scrollBar.Maximum != newMaximuum)
{
scrollBar.IsEnabled = newEnabled;
scrollBar.Maximum = newMaximuum;
scrollBar.SmallChange = parameter.SmallChange;
scrollBar.LargeChange = parameter.LargeChange;
scrollBar.SetThumbLength(newThumbLength);
scrollBar.SetThumbCenter(newThumbCenter);
}
}
}
private (double startValue, double endValue) GetValueRange(System.Windows.Controls.Primitives.ScrollBar scrollBar)
{
double thumbLength = scrollBar.GetThumbLength();
double thumbCenter = scrollBar.GetThumbCenter();
double startValue = thumbCenter - thumbLength / 2;
double endValue = thumbCenter + thumbLength / 2;
double sv = startValue < 0 ? 0 : startValue > 1 ? 1 : startValue;
double ev = endValue < 0 ? 0 : endValue > 1 ? 1 : endValue;
return(sv, ev);
}