HeatmapDataSourceAdapter Class

Loads heatmap data from a data source.

Namespace: DevExpress.XtraCharts.Heatmap

Assembly: DevExpress.XtraCharts.v21.2.dll

NuGet Package: DevExpress.Charts

Declaration

C#

public class HeatmapDataSourceAdapter :
    HeatmapDataAdapterBase,
    IHeatmapDataSourceProvider,
    IHeatmapAdapter,
    IDataSourceChangedEventHandlerProvider,
    IServiceProviderHolder,
    IBindingPropertiesProvider

VB.NET

Public Class HeatmapDataSourceAdapter
    Inherits HeatmapDataAdapterBase
    Implements 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:

• 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:

  • XArgumentDataMember
  • YArgumentDataMember

• 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.

C#

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;
        }
    }
}

VB.NET

Imports DevExpress.XtraCharts
Imports DevExpress.XtraCharts.Heatmap
Imports System
Imports System.Data
Imports System.Drawing
Imports System.IO
Imports System.Windows.Forms

Namespace HeatmapChart
    Public Partial Class Form1
        Inherits Form

        Public Sub New()
            InitializeComponent()
        End Sub

        Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs)
            Dim heatmap As HeatmapControl = New HeatmapControl()
            heatmap.Dock = DockStyle.Fill
            Me.Controls.Add(heatmap)

            Dim palette As Palette = New Palette("Custom") From {
                System.Drawing.Color.Red,
                System.Drawing.Color.White,
                System.Drawing.Color.Green
            }
            Dim colorProvider As HeatmapRangeColorProvider = New HeatmapRangeColorProvider() With {
                .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
            Dim data As System.Data.DataTable = HeatmapChart.Form1.CreateDataSet("BalanceOfTrade.xml")
            heatmap.DataAdapter = New HeatmapDataSourceAdapter() With {
                .XArgumentDataMember = "Country",
                .YArgumentDataMember = "Product",
                .ColorDataMember = "Value",
                .DataSource = data                
            }
            heatmap.Titles.Add(New HeatmapTitle With {
                .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 With {
                .AllowHtmlText = True,
                .ToolTipLocation = DevExpress.Utils.ToolTipLocation.RightTop,
                .ShowBeak = True
            }
            heatmap.ToolTipTextPattern = "X: <b>{X}</b>" & Global.Microsoft.VisualBasic.Constants.vbLf & "Y: <b>{Y}</b>"
        End Sub

        Public Shared Function CreateDataSet(ByVal xmlFileName As String) As System.Data.DataTable
            Dim filePath As String = HeatmapChart.Form1.GetRelativePath(xmlFileName)

            If Not String.IsNullOrWhiteSpace(filePath) Then
                Dim dataSet As System.Data.DataSet = New System.Data.DataSet()
                dataSet.ReadXml(filePath)
                If dataSet.Tables.Count > 0 Then Return dataSet.Tables(0)
            End If

            Return Nothing
        End Function

        Public Shared Function GetRelativePath(ByVal name As String) As String
            name = "Data\" & name
            Dim dir As System.IO.DirectoryInfo = New System.IO.DirectoryInfo(Application.StartupPath)

            For i As Integer = 0 To 10
                Dim filePath As String = System.IO.Path.Combine(dir.FullName, name)
                If System.IO.File.Exists(filePath) Then Return filePath
                dir = System.IO.Directory.GetParent(dir.FullName)
            Next

            Return String.Empty
        End Function
    End Class
End Namespace

The XML file structure looks as follows:

Show XML

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