Ok, I can see it now. This issue here is that you have string labels, not data values. You can try using IRenderLabel interface:

this.ultraChart1.Axis.X.Labels.ItemFormatString = "<MY_VALUE>";

Hashtable MyLabelHashTable = new Hashtable();

MyLabelHashTable.Add("MY_VALUE", new MyLabelRenderer());

this.ultraChart1.LabelHash = MyLabelHashTable;

…

public class MyLabelRenderer : IRenderLabel

    {

        public string ToString(Hashtable context)

        {

            string label = (string)context["ITEM_LABEL"];

            double value = Convert.ToDouble(label);

            return value.ToString("0.00##");

        }

    }

Sorry, I meant I don't have problem with Y axis. I only have problem in X axis.

I have no problem with x and z axis. I seem to have problem in Y axis. I wonder if there's something to do with how I assemble the data source. Attached is the data source I set in the chart. If I understand correctly, the chart uses the columns for Y-axis labels. Is that correct? Maybe there is something I have not done it right?

I’ve been trying:

this.ultraChart1.ChartType = Infragistics.UltraChart.Shared.Styles.ChartType.HeatMapChart3D;

this.ultraChart1.DataSource = DemoTable.BoxChartData;

this.ultraChart1.DataBind();

this.ultraChart1.Axis.Y.Labels.ItemFormatString = "<DATA_VALUE:0.00##>";

And it seems ok. I’m not really sure what the issue with your code is.