if you set value here too, another quide will be drawn. If you set fill alpha greater 0, then the area between these quides will be filled with color

public Nullable<decimal> EndValue { get; set; }

Public Property EndValue As Nullable(Of Decimal)

public:
property Nullable<Decimal> EndValue {
	Nullable<Decimal> get ();
	void set (Nullable<Decimal> value);
}