ItemsLayerLegend.Layer Property
Specifies the layer from which the legend obtains data to display.
Namespace: DevExpress.XtraMap
Assembly: DevExpress.XtraMap.v18.2.dll
Declaration
Property Value
| Type | Default | Description |
|---|---|---|
| MapItemsLayerBase | *null* | A MapItemsLayerBase class descendant. |
Example
This example demonstrates how to generate bubble charts for a map control. Do the following:
- Create a VectorItemsLayer object and add it to the map control.
- Create a BubbleChartDataAdapter object and assign it to the VectorItemsLayer.Data property.
- Generate a data source with data for bubble charts and assign it to the DataSourceAdapterBase.DataSource property.
- Specify the mappings for bubble chart properties to corresponding columns in a datasource (a MapBubbleMappingInfo object that can be accessed using the BubbleChartDataAdapter.Mappings property).
- Specify the attribute mappings that are used to provide additional information about the map item to a map control.(an MapItemAttributeCollection object that can be accessed using the BubbleChartDataAdapter.Mappings property).
Note
A complete sample project is available at https://github.com/DevExpress-Examples/how-to-display-bubble-chart-items-on-a-map-t113410
// Specify data for the bubble layer.
BubbleLayer.Data = CreateData();
private IMapDataAdapter CreateData() {
BubbleChartDataAdapter adapter = new BubbleChartDataAdapter() {
DataSource = LoadData(),
MeasureRules = CreateMeasureRules(),
ItemMaxSize = 60,
ItemMinSize = 10
};
#region #Mappings
// Map the properties of chart items to the appropriate fields in the data source.
adapter.Mappings.Latitude = "glat";
adapter.Mappings.Longitude = "glon";
adapter.Mappings.Value = "mag";
#endregion #Mappings
// Create attribute mappings to provide additional information about map items to the map.
adapter.AttributeMappings.Add(new MapItemAttributeMapping("Magnitude", "mag"));
adapter.AttributeMappings.Add(new MapItemAttributeMapping("Year", "yr"));
adapter.AttributeMappings.Add(new MapItemAttributeMapping("Month", "mon"));
adapter.AttributeMappings.Add(new MapItemAttributeMapping("Day", "day"));
adapter.AttributeMappings.Add(new MapItemAttributeMapping("Depth", "dep"));
return adapter;
}
private DataTable LoadData() {
DataSet ds = new DataSet();
ds.ReadXml(dataPath);
DataTable dt = ds.Tables[0];
dt.DefaultView.RowFilter = string.Format(CultureInfo.InvariantCulture, "(mag >= {0}) AND (mag <= {1})", minMagnitude, maxMagnitude);
return ds.Tables[0];
}
private MeasureRules CreateMeasureRules() {
MeasureRules measureRules = new MeasureRules();
measureRules.ApproximateValues = true;
measureRules.RangeDistribution = new LinearRangeDistribution();
for (int i = minMagnitude; i < maxMagnitude; i++) {
measureRules.RangeStops.Add(i);
}
return measureRules;
}
Related GitHub Examples
The following code snippet (auto-collected from DevExpress Examples) contains a reference to the Layer property.
Note
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