Skip to main content
All docs
V24.1

HeatmapDataSourceAdapter Class

Loads heatmap data from a data source.

Namespace: DevExpress.XtraCharts.Heatmap

Assembly: DevExpress.XtraCharts.v24.1.dll

NuGet Package: DevExpress.Charts

Declaration

[DataAccessMetadata("All", SupportedProcessingModes = "Simple", Platform = "Win", EnableDirectBinding = false)]
public class HeatmapDataSourceAdapter :
    HeatmapDataAdapterBase,
    IHeatmapDataSourceProvider,
    IHeatmapAdapter,
    IDataSourceChangedEventHandlerProvider,
    IServiceProviderHolder,
    IBindingPropertiesProvider

Remarks

Use the HeatmapControl.DataAdapter to assign a HeatmapDataSourceAdapter to a heatmap. Specify the following adapter properties to load data to the heatmap:

Example

The following example shows how to create a heatmap and bind it to a data source. In this example, the heatmap obtains data from an XML file.

A heatmap that uses a Data Source Adapter to load data.

Follow the steps below to create a heatmap:

using DevExpress.XtraCharts;
using DevExpress.XtraCharts.Heatmap;
using System;
using System.Data;
using System.Drawing;
using System.IO;
using System.Windows.Forms;

namespace HeatmapChart {
    public partial class Form1 : Form {
        public Form1() {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e) {
            HeatmapControl heatmap = new HeatmapControl();
            heatmap.Dock = DockStyle.Fill;
            this.Controls.Add(heatmap);

            Palette palette = new Palette("Custom") {
                Color.Red,
                Color.White,
                Color.Green
            };

            HeatmapRangeColorProvider colorProvider = new HeatmapRangeColorProvider() {
                Palette = palette,
                ApproximateColors = true
            };

            colorProvider.RangeStops.Add(new HeatmapRangeStop(0, HeatmapRangeStopType.Percentage));
            colorProvider.RangeStops.Add(new HeatmapRangeStop(-10, HeatmapRangeStopType.Absolute));
            colorProvider.RangeStops.Add(new HeatmapRangeStop(-2.5, HeatmapRangeStopType.Absolute));
            colorProvider.RangeStops.Add(new HeatmapRangeStop(0, HeatmapRangeStopType.Absolute));
            colorProvider.RangeStops.Add(new HeatmapRangeStop(2.5, HeatmapRangeStopType.Absolute));
            colorProvider.RangeStops.Add(new HeatmapRangeStop(10, HeatmapRangeStopType.Absolute));
            colorProvider.RangeStops.Add(new HeatmapRangeStop(1, HeatmapRangeStopType.Percentage));

            heatmap.ColorProvider = colorProvider;

            DataTable data = CreateDataSet("BalanceOfTrade.xml");

            heatmap.DataAdapter = new HeatmapDataSourceAdapter() {
                XArgumentDataMember = "Country",
                YArgumentDataMember = "Product",
                ColorDataMember = "Value",
                DataSource = data                
            };

            heatmap.Titles.Add(new HeatmapTitle { Text = "Balance of Trade" });

            heatmap.Label.Visible = true;
            heatmap.Label.Font = new Font("SegoeUI", 6);
            heatmap.Label.Pattern = "{V}";

            heatmap.ToolTipEnabled = true;
            heatmap.ToolTipController = new DevExpress.Utils.ToolTipController {
                AllowHtmlText = true,
                ToolTipLocation = DevExpress.Utils.ToolTipLocation.RightTop,
                ShowBeak = true
            };
            heatmap.ToolTipTextPattern = "X: <b>{X}</b>\nY: <b>{Y}</b>";
        }
        public static DataTable CreateDataSet(string xmlFileName) {
            string filePath = GetRelativePath(xmlFileName);
            if (!string.IsNullOrWhiteSpace(filePath)) {
                DataSet dataSet = new DataSet();
                dataSet.ReadXml(filePath);
                if (dataSet.Tables.Count > 0)
                    return dataSet.Tables[0];
            }
            return null;
        }
        public static string GetRelativePath(string name) {
            name = "Data\\" + name;
            DirectoryInfo dir = new DirectoryInfo(Application.StartupPath);
            for (int i = 0; i <= 10; i++) {
                string filePath = Path.Combine(dir.FullName, name);
                if (File.Exists(filePath))
                    return filePath;
                dir = Directory.GetParent(dir.FullName);
            }
            return string.Empty;
        }
    }
}

The XML file structure looks as follows:

Show XML
<?xml version="1.0" standalone="yes"?>
<BalanceOfTrade xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <xs:element name="Item">
      <xs:complexType>
        <xs:sequence>
          <xs:element name="Country" type="xs:string"/>
          <xs:element name="Product" type="xs:string"/>
          <xs:element name="Value" type="xs:double"/>
        </xs:sequence>
      </xs:complexType>
    </xs:element>
  </xs:schema>
  <Item>
    <Country>China</Country>
    <Product>Computer</Product>
    <Value>-151.9</Value>
  </Item>
  <Item>
    <Country>China</Country>
    <Product>Oil, Gas, Minerals</Product>
    <Value>1.9</Value>
  </Item>
  <Item>
    <Country>China</Country>
    <Product>Transportation</Product>
    <Value>10.9</Value>
  </Item>
  <Item>
    <Country>China</Country>
    <Product>Apparel</Product>
    <Value>-56.3</Value>
  </Item>
  <!--...-->
</BalanceOfTrade>     

Inheritance

Object
DevExpress.XtraCharts.Native.NotificationElement
HeatmapDataAdapterBase
HeatmapDataSourceAdapter
See Also