The requested page is not available for the requested platform. You are viewing the content for .NET Framework 4.5.2+ platform.

Display Areas on a Vector Map

  • 3 min to read

This topic describes how to show business objects as areas on a vector map.

Run the Application Designer for the ASP.NET application project. Drag the MapsAspNetModule component from the Toolbox to the designer's Modules pane.

MapsModule_Toolbox

Implement the business class that supports the IAreaInfo interface. In the code below, a new Country business class is created. You can also support IAreaInfo in an existing business class.

using DevExpress.Persistent.Base;
// ...
[DefaultClassOptions]
public class Country : IAreaInfo {
    [Browsable(false)]
    public int ID { get; set; }
    public string Title {
        get;
        set;
    }
    [Browsable(false)]
    public string Tooltip {
        get { return string.Format("<b>{0}</b><br/>Value = {1}", Title, Value); }
    }
    public float Value {
        get;
        set;
    }
}

The IAreaInfo.Tooltip return value supports HTML formatting. The first line of the tooltip will be the country name using the bold font, and the second will display the value associated with the current country.

Note

The example above is for the Entity Framework. However, you can use a similar approach in an XPO persistent class. You can find the complete example for XPO in the Feature Center demo (see %PUBLIC%\Documents\DevExpress Demos 19.2\Components\eXpressApp Framework\FeatureCenter\CS\FeatureCenter.Module\ListEditors\VectorMapsListEditorDemoObject.cs).

Run the Model Editor for the ASP.NET application project and navigate to the Views | Location_ListView | VectorMapSettings node. Here, you can change the map options. For instance, set the IModelVectorMapSettings.Type property to Eurore.

VectorMapSettings.Type

Refer to the member list of the IModelMapSettings interface to see the descriptions of available options.

Tip

Note that the IModelListView.EditorType property of the Country_ListView node is set to WebVectorMapsListEditor. This is done automatically for any List View that displays IAreaInfo objects.

The VectorMapSettings | IntervalItems node (see IModelIntervalItems) allows you to categorize map areas by their associated values. You can use the Add... | IntervalItem context menu command to add the child IModelIntervalItem nodes to define bounds of categories.

VectorMapSettings_AddInterval

For instance, you can create the First, Second and Max child nodes with the following property values.

IModelNode.Index IModelIntervalItem.Title IModelIntervalItem.Value
1 First 1
2 Second 10
3 Max 20

The following image demonstrates these nodes.

VectorMaps_IntervalItems

As a result, map areas whose values are in the 1...10 interval will be classified as "First". Map areas whose values are in the 10...20 interval will be classified as "Second".

Run the ASP.NET application. The Country List View is visualized using the MapViewer control. You can create areas using theNew Action.

VectorMaps_NewCountry

For instance, create the following Countries.

IAreaInfo.Title IAreaInfo.Value
France 7
Germany 12

The resulting map is demonstrated below. France and Germany are highlighted with different colors because their associated values are in different intervals. Intervals and their colors are listed in the map legend located in the bottom right corner of the map.

VectorMaps_AreasTooltipLegend

The Detail View is shown when you click a country. For instance, click France and change the Value to 13. As a result, France and Germany will be highlighted with the same color because their associated values are in the same interval.

VectorMaps_AreasTooltipLegend2

Tip

You can change the color palette using the IModelVectorMapSettings.Palette property of the VectorMapSettings node in the Model Editor.

See Also