https://learn.microsoft.com/en-us/dotnet/api/system.windows.controls.primitives.rangebase.valuechanged?view=netframework-4.8.1&viewFallbackFrom=windowsdesktop-10.0
RangeBase.ValueChanged Event (System.Windows.Controls.Primitives) | Microsoft Learn
Occurs when the range value changes.
event systemvaluechangedwindowscontrolsprimitives