private void RangeSlider_LowerThumbDragCompleted(object sender, System.Windows.Controls.Primitives.DragCompletedEventArgs e)
{
var thump = e.OriginalSource as MahApps.Metro.Controls.MetroThumb;
var range = thump.TemplatedParent as MahApps.Metro.Controls.RangeSlider;
lowerValue = Convert.ToInt32(range.LowerValue);
PriceTitle.Text = $"{lowerValue} TL - {upperValue} TL";
content.OrderByLowPrice(lowerValue);
}