/// <inheritdoc/> protected override void OnChecked() { var parent = LogicalTreeHelper.GetParent(this); if (parent != null) { var children = LogicalTreeHelper.GetChildrenCount(parent); for (int i = 0; i < children; i++) { var sibling = LogicalTreeHelper.GetChild(parent, i); if (sibling == this) { continue; } var radioButton = sibling as RadioButton; if (radioButton == null) { continue; } radioButton.IsChecked = false; } } base.OnChecked(); }