Line chart not displaying line when Y values are all equal

[Boyan]

Hi,

I am using RadControls Ajax Q3 2010.

I have a very simple graph 

<telerik:RadChart ID="chtPrices" runat="server" DefaultType="Line" Width="500px"
                Height="300px" AutoLayout="true">
                <ChartTitle Visible="false" />
                <Legend Visible="false" />
                <PlotArea>
                    <XAxis Visible="True" />
                    <YAxis ScaleBreaks-Enabled="true" IsZeroBased="false" />
                    <EmptySeriesMessage TextBlock-Text="No Data Selected"/>
                </PlotArea>
            </telerik:RadChart>

and I set its data source dynamically

DataTable prices = PricessManager.GetPrices();
chtPrices.DataSource = prices;
chtPrices.DataBind();

When the data in the data table contains several values (doubles) that are the same (say 91.1, 91.1, 91.1, etc), the graph does not draw the line and instead of centering the graph around 91.1 (since IsZeroBased is set to false), it centers it around 0 which leads me to believe for some reason it's not taking the values at all.

When the same exact data table but with various numbers (say 91, 92, 84.3, 96.1, etc) is used to set the data source, the graph works fine.

Any thoughts?

[Petar Marchev]

Hi Boyan,

Unfortunately, this is a bug in the control. Because all values are equal there is no delta and the axis can't work with the delta being zero.  Fortunately, I can suggest a workaround -- you can set IsZeroBased to false only if there are at least two items with distinct YValues, and leave it with the default value (true) if all items have the same YValue. You can use the DataBound event of RadChart for this.

Additionaly, you can configure the axis manually in case all items have the same Y values. Just set AutoScale to false and use your own MinValue, MaxValue and Step, which can depend on the YValue of the ChartSeriesItems.

All the best,
Petar Marchev
the Telerik team