public CalendarElementStyle CellDisabledStyle { get; }

Public ReadOnly Property CellDisabledStyle As CalendarElementStyle

<dx:ASPxDateEdit runat="server" ID="dateEdit2" PickerType="Months">
    <CalendarProperties>
        <CellDisabledStyle BackColor="Red" />
        <CellOtherPeriodStyle BackColor="YellowGreen" />
        <CellOutOfRangeStyle BackColor="DarkBlue" />
        <CellSelectedStyle BackColor="Aqua" />
        <CellStyle BackColor="RosyBrown" />
    </CalendarProperties>
</dx:ASPxDateEdit>