Telerik chart series tooltip and color

[p]

1) Is it possible to change the color of a line chart depending on the value?
e.g If the value is less than a threshold value it is green. Once the line passes the threshold the color should be red.

2) Is it possible to show a tooltip between the PointMarks. My X-axis is time and depending on the hover location i want to show an image on the tooltip.


Thanks

[Danail Vasilev]

Hello,

Please find below my answers to your questions:

• Conditional Item Colorization - the RadChart control doesn't support conditional item colorization out of the box. What you can do, however, in order to achieve that is to iterate through each series item and depending on the YValue assign desired colors for the PointMarks/Items. For example:

ASPX:

<telerik:RadChart ID="RadChart1" runat="server">
    <Series>
        <telerik:ChartSeries Type="Line">
            <Appearance>
                <PointMark Visible="true" Figure="Rectangle">
                    <FillStyle MainColor="Yellow"></FillStyle>
                    <Border Color="Gray" Width="2" />
                </PointMark>
            </Appearance>
            <Items>
                <telerik:ChartSeriesItem YValue="10">
                </telerik:ChartSeriesItem>
                <telerik:ChartSeriesItem YValue="30"></telerik:ChartSeriesItem>
                <telerik:ChartSeriesItem YValue="20"></telerik:ChartSeriesItem>
                <telerik:ChartSeriesItem YValue="25"></telerik:ChartSeriesItem>
            </Items>
        </telerik:ChartSeries>
    </Series>
</telerik:RadChart>

C#:

protected void Page_Load(object sender, EventArgs e)
{
    for (int i = 0; i < RadChart1.Series[0].Items.Count; i++)
    {
        Telerik.Charting.ChartSeriesItem currItem = RadChart1.Series[0].Items[i];
        if (currItem.YValue > 20)
        {
            currItem.PointAppearance.FillStyle.MainColor = System.Drawing.Color.Red;
            currItem.PointAppearance.Border.Color = System.Drawing.Color.Red;
        }
        else if (currItem.YValue < 15)
        {
            currItem.PointAppearance.FillStyle.MainColor = System.Drawing.Color.Green;
            currItem.PointAppearance.Border.Color = System.Drawing.Color.Green;
        }
    }
}

• ToolTips position - currently the ToolTips of the RadChart doesn't support control over their position. What you can do, however, in order to achieve that is to integrate the RadToolTip control which supports the controlling of the position. More information on this integration is available in Chart - Item Tooltips in Radchart online demo.

Regards,
Danail Vasilev
Telerik