Two colour in one column in chart ASP.NET C#

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C#

ASP.NET

chart

Hello every one,
I'm working on chart in asp.net and c#, I built the chart and is working good, but I'm looking for something like different colour in the same column

for example the yaxies from 0 to 8
I want the column start from 0 to 3 in red colour and from 3 to 8 in green colour

I have this code for chart

<asp:Chart ID="Chart7" runat="server">
            <Series>
                <asp:Series Name="Series1" XValueMember="file" YValueMembers="time" IsVisibleInLegend="true">
                </asp:Series>
            </Series>
            <ChartAreas>
                <asp:ChartArea Name="ChartArea1">
                    <AxisY Minimum="0" Maximum="8" Interval="1"></AxisY>
                </asp:ChartArea>
            </ChartAreas>
        </asp:Chart>

What I have tried:

I try to do it in code behind in c# but it does not work
Chart7.Series[0].Points[3].Color=System.Drawing.Color.Red;

Any suggestion ??