HeatmapDataSourceAdapter Class
Loads heatmap data from a data source.
Namespace: DevExpress.XtraCharts.Heatmap
Assembly: DevExpress.XtraCharts.v21.2.dll
Declaration
public class HeatmapDataSourceAdapter :
HeatmapDataAdapterBase,
IHeatmapDataSourceProvider,
IHeatmapAdapter,
IDataSourceChangedEventHandlerProvider,
IServiceProviderHolder,
IBindingPropertiesProviderRemarks
Use the HeatmapControl.DataAdapter to assign a HeatmapDataSourceAdapter to a heatmap. Specify the following adapter properties to load data to the heatmap:
- DataSource – Specifies a data source. You can assign this property an object that implements any of the following interfaces: IList, IListSource, or IBindingList.
- ColorDataMember – Defines a data member that a color provider uses to determine cell colors.
- XArgumentDataMember – Specifies a data member that stores x-arguments.
- YArgumentDataMember – Specifies a data member that stores y-arguments.
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.
Follow the steps below to create a heatmap:
- Add the HeatmapControl to the Form.
- Create a HeatmapDataSourceAdapter object and assign it to the HeatmapControl.DataAdapter property.
- Define the adapter’s DataSource property.
- Use the ColorDataMember property to define a data member that is used to determine cell colors.
Specify the following adapter properties to define data members that store heatmap arguments:
Create a HeatmapRangeColorProvider object and assign it to the heatmap’s ColorProvider property. The HeatmapRangeColorProvider paints cells based on a value range to which the cell value belongs.
- Add a HeatmapTitle to the heatmap’s Titles collection. Specify the title’s Text property.
- Use the heatmap’s Label property to configure cell label options. This example shows how to configure label text format.
- Set the HeatmapControl.ToolTipEnabled property to true to enable tooltips. Specify the HeatmapControl.ToolTipTextPattern property to define tooltip text display format.
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>
Related GitHub Examples
The following code snippets (auto-collected from DevExpress Examples) contain references to the HeatmapDataSourceAdapter class.
Note
The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.
Inheritance
Object
DevExpress.XtraCharts.Native.NotificationElement
HeatmapDataAdapterBase
HeatmapDataSourceAdapter
See Also
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