[C1Description("Chart2DArea.MarginBottom", "The bottom margin of chart area in twips. -1 will allow for margin auto-positioning.")]
[TypeConverter(typeof(PageUnitConverter))]
public double MarginBottom { get; set; }

<C1Description("Chart2DArea.MarginBottom", "The bottom margin of chart area in twips. -1 will allow for margin auto-positioning.")>
<TypeConverter(GetType(PageUnitConverter))>
Public Property MarginBottom As Double