When comma is the decimal seperator (check within debug and debugging panels)
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then we can convert / check by
Double.Parse("12345,12456", System.Globalization.CultureInfo.CreateSpecificCulture("de-DE"))
Double.TryParse("12345,12456",NumberStyles.Any,System.Globalization.CultureInfo.CreateSpecificCulture("de-DE").NumberFormat,nothing)