protected virtual void OnExternalChange(ExternalChangeEventArgs e)
{
AssertValid();
EventHandler <ExternalChangeEventArgs> h = externalChange;
if (h != null)
{
h(this, e);
}
}
protected virtual void OnExternalChange(ExternalChangeEventArgs e)
{
GetCheckedHandle();
var h = externalChange;
if (h is not null)
{
h(this, e);
}
}