MapItemAttribute.Type Property

Specifies a type of the map item attribute mapping.

Namespace: DevExpress.XtraMap

Assembly: DevExpress.XtraMap.v24.1.dll

NuGet Package: DevExpress.Win.Map

Declaration

C#

[Browsable(false)]
[DefaultValue(null)]
[EditorBrowsable(EditorBrowsableState.Never)]
public Type Type { get; set; }

VB.NET

<DefaultValue(Nothing)>
<Browsable(False)>
<EditorBrowsable(EditorBrowsableState.Never)>
Public Property Type As Type

Property Value

Type	Default	Description
Type	null	A map item attribute type.

Example

This example demonstrates how to paint two triangles on a map using the choropleth colorizer.

To accomplish this task for map shapes, do the following:

• Create a choropleth colorizer using the VectorItemsLayer.Colorizer property;
• Specify range stops (data splits in ranges) for the colorizer using the ChoroplethColorizer.RangeStops property;
• Specify a set of colors in the GenericColorizerItemCollection<T> object, which is accessed via the ChoroplethColorizer.ColorItems property;
• Create a MapItemAttribute object using the MapItem.Attributes property;
• Specify the attribute name, type, and value using the corresponding properties (MapItemAttribute.Name, MapItemAttribute.Type, and MapItemAttribute.Value);
• Assign the ShapeAttributeValueProvider object with the specified attribute name (ShapeAttributeValueProvider.AttributeName) to the ChoroplethColorizer.ValueProvider property.

Form1.cs

using DevExpress.Utils;
using DevExpress.XtraMap;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;

namespace Manual_Colorization {
    public partial class Form1 : Form {
        const string areaValueAttrName = "AreaValue";
        const string polygonNameAttrName = "PolygonName";

        public Form1() {
            InitializeComponent();

            InitializeMap();
        }

        void InitializeMap() {
            // Create a map control and add it to the form.
            MapControl map = new MapControl() { Dock = DockStyle.Fill };
            this.Controls.Add(map);

            // Create a layer to display vector data.
            VectorItemsLayer itemsLayer = new VectorItemsLayer();
            map.Layers.Add(itemsLayer);

            // Generate a data storage for the layer.
            itemsLayer.Data = CreateData();

            // Create a colorizer for the layer.
            itemsLayer.Colorizer = CreateColorizer();

            // Create a legend for the layer.
            map.Legends.Add(CreateLegend(itemsLayer));

            // Specify tooltips for the map.
            map.ToolTipController = new ToolTipController() { AllowHtmlText = true };
        }

        private MapItemStorage CreateData() {
            MapItemStorage storage = new MapItemStorage();

            // Create the first triangle.
            storage.Items.Add(
                CreatePolygon(800, "Small triangle",
                    new GeoPoint[] { 
                        new GeoPoint(0, 0), new GeoPoint(0, 40), 
                        new GeoPoint(40, 0), new GeoPoint(0, 0) 
                    }
                 )
             );

            // Create the second triangle.
            storage.Items.Add(
                CreatePolygon(1800, "Large triangle",
                    new GeoPoint[] { 
                        new GeoPoint(0, 0), new GeoPoint(0, -60), 
                        new GeoPoint(-60, 0), new GeoPoint(0, 0) 
                    }
                )
             );

            return storage;
        }

        #region #CreatePolygon
        private MapPolygon CreatePolygon(double areaValue, string polygonName, GeoPoint[] points) {
            MapPolygon item = new MapPolygon();

            item.Attributes.Add(new MapItemAttribute() {
                Name = areaValueAttrName,
                Type = typeof(double),
                Value = areaValue
            });
            item.Attributes.Add(new MapItemAttribute() {
                Name = polygonNameAttrName,
                Type = typeof(string),
                Value = polygonName
            });

            item.ToolTipPattern = "{" + polygonNameAttrName + "}=<b>{" + areaValueAttrName + "}</b>";

            foreach (GeoPoint point in points) {
                item.Points.Add(point);
            }

            return item;
        }
        #endregion #CreatePolygon

        private MapColorizer CreateColorizer() {
            ChoroplethColorizer colorizer = new ChoroplethColorizer();
            colorizer.ValueProvider = new ShapeAttributeValueProvider {
                AttributeName = areaValueAttrName
            };

            colorizer.RangeStops.AddRange(new List<double> { 0, 1000, 2000 });
            colorizer.ColorItems.AddRange(new List<ColorizerColorItem> {
                new ColorizerColorItem(Color.Yellow),
                new ColorizerColorItem(Color.Red)
            });

            return colorizer;
        }

        private MapLegendBase CreateLegend(MapItemsLayerBase layer) {
            ColorScaleLegend legend = new ColorScaleLegend();
            legend.Header = "Area";
            legend.Layer = layer;
            return legend;
        }
    }

}

Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;

namespace Manual_Colorization {
    static class Program {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main() {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
        }
    }
}

Form1.vb

Imports DevExpress.Utils
Imports DevExpress.XtraMap
Imports System.Collections.Generic
Imports System.Drawing
Imports System.Windows.Forms

Namespace Manual_Colorization
    Partial Public Class Form1
        Inherits Form

        Private Const areaValueAttrName As String = "AreaValue"
        Private Const polygonNameAttrName As String = "PolygonName"

        Public Sub New()
            InitializeComponent()

            InitializeMap()
        End Sub

        Private Sub InitializeMap()
            ' Create a map control and add it to the form.
            Dim map As New MapControl() With {.Dock = DockStyle.Fill}
            Me.Controls.Add(map)

            ' Create a layer to display vector data.
            Dim itemsLayer As New VectorItemsLayer()
            map.Layers.Add(itemsLayer)

            ' Generate a data storage for the layer.
            itemsLayer.Data = CreateData()

            ' Create a colorizer for the layer.
            itemsLayer.Colorizer = CreateColorizer()

            ' Create a legend for the layer.
            map.Legends.Add(CreateLegend(itemsLayer))

            ' Specify tooltips for the map.
            map.ToolTipController = New ToolTipController() With {.AllowHtmlText = True}
        End Sub

        Private Function CreateData() As MapItemStorage
            Dim storage As New MapItemStorage()

            ' Create the first triangle.
            storage.Items.Add(CreatePolygon(800, "Small triangle", New GeoPoint() { _
                New GeoPoint(0, 0), _
                New GeoPoint(0, 40), _
                New GeoPoint(40, 0), _
                New GeoPoint(0, 0) _
            }))

            ' Create the second triangle.
            storage.Items.Add(CreatePolygon(1800, "Large triangle", New GeoPoint() { _
                New GeoPoint(0, 0), _
                New GeoPoint(0, -60), _
                New GeoPoint(-60, 0), _
                New GeoPoint(0, 0) _
            }))

            Return storage
        End Function

        #Region "#CreatePolygon"
        Private Function CreatePolygon(ByVal areaValue As Double, ByVal polygonName As String, ByVal points() As GeoPoint) As MapPolygon
            Dim item As New MapPolygon()

            item.Attributes.Add(New MapItemAttribute() With {.Name = areaValueAttrName, .Type = GetType(Double), .Value = areaValue})
            item.Attributes.Add(New MapItemAttribute() With {.Name = polygonNameAttrName, .Type = GetType(String), .Value = polygonName})

            item.ToolTipPattern = "{" & polygonNameAttrName & "}=<b>{" & areaValueAttrName & "}</b>"

            For Each point As GeoPoint In points
                item.Points.Add(point)
            Next point

            Return item
        End Function
        #End Region ' #CreatePolygon

        Private Function CreateColorizer() As MapColorizer
            Dim colorizer As New ChoroplethColorizer()
            colorizer.ValueProvider = New ShapeAttributeValueProvider With {.AttributeName = areaValueAttrName}

            colorizer.RangeStops.AddRange(New List(Of Double) From {0, 1000, 2000})
            colorizer.ColorItems.AddRange(New List(Of ColorizerColorItem) From { _
                New ColorizerColorItem(Color.Yellow), _
                New ColorizerColorItem(Color.Red) _
            })

            Return colorizer
        End Function

        Private Function CreateLegend(ByVal layer As MapItemsLayerBase) As MapLegendBase
            Dim legend As New ColorScaleLegend()
            legend.Header = "Area"
            legend.Layer = layer
            Return legend
        End Function
    End Class

End Namespace

Program.vb

Imports System
Imports System.Collections.Generic
Imports System.Linq
Imports System.Windows.Forms

Namespace Manual_Colorization
    Friend NotInheritable Class Program

        Private Sub New()
        End Sub

        ''' <summary>
        ''' The main entry point for the application.
        ''' </summary>
        <STAThread> _
        Shared Sub Main()
            Application.EnableVisualStyles()
            Application.SetCompatibleTextRenderingDefault(False)
            Application.Run(New Form1())
        End Sub
    End Class
End Namespace