https://learn.microsoft.com/en-us/dotnet/api/system.windows.media.visualtreehelper.getchildrencount?view=netframework-4.8.1&viewFallbackFrom=windowsdesktop-9.0
VisualTreeHelper.GetChildrenCount(DependencyObject) Method (System.Windows.Media) | Microsoft Learn
Returns the number of children that the specified visual object contains.
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