MapItem.Tag Property

Gets or sets the object that contains data related to a map item.

Namespace: DevExpress.XtraMap

Assembly: DevExpress.XtraMap.v23.2.dll

NuGet Package: DevExpress.Win.Map

Declaration

C#

[DefaultValue(null)]
public object Tag { get; set; }

VB.NET

<DefaultValue(Nothing)>
Public Property Tag As Object

Property Value

Type	Default	Description
Object	null	A Object that contains information about the map item.

Remarks

Any type derived from the Object class can be assigned to this property. Use it to store data associated with a map item.

Example

The following example adds two pushpins to a map item storage. Each pushpin’s Tag property is initialized with an object of the ItemInfo type. The storage’s DataChanged event handler defines pushpins’ visibility based on the ItemInfo.IsOpened property value.

C#

VectorItemsLayer vectorLayer;
//...
private void Form1_Load(object sender, EventArgs e) {

    vectorLayer = new VectorItemsLayer();
    mapControl1.Layers.Add(vectorLayer);

    MapItemStorage storage = new MapItemStorage();
    vectorLayer.Data = storage;

    storage.DataChanged += Storage_DataChanged;

    MapPushpin pushpin1 = new MapPushpin();
    pushpin1.Location = new GeoPoint(48.862644, 2.336578);
    pushpin1.Tag = new ItemInfo { IsOpened = true };
    storage.Items.Add(pushpin1);

    MapPushpin pushpin2 = new MapPushpin();
    pushpin2.Location = new GeoPoint(59.9398, 30.3146);
    pushpin2.Tag = new ItemInfo { IsOpened = false };
    storage.Items.Add(pushpin2);

}

private void Storage_DataChanged(object sender, DataAdapterChangedEventArgs e) {
    foreach (MapItem item in vectorLayer.Data.Items) {
        ItemInfo info = item.Tag as ItemInfo;
        item.Visible = info.IsOpened;
    }
}

public class ItemInfo {
    public bool IsOpened { get; set; }
}

VB.NET

Private vectorLayer As VectorItemsLayer

  '...
  Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs)
      vectorLayer = New VectorItemsLayer()
      mapControl1.Layers.Add(vectorLayer)
      Dim storage As MapItemStorage = New MapItemStorage()
      vectorLayer.Data = storage
      storage.DataChanged += AddressOf Storage_DataChanged
      Dim pushpin1 As MapPushpin = New MapPushpin()
      pushpin1.Location = New GeoPoint(48.862644, 2.336578)
      pushpin1.Tag = New ItemInfo With {
          .IsOpened = True
      }
      storage.Items.Add(pushpin1)
      Dim pushpin2 As MapPushpin = New MapPushpin()
      pushpin2.Location = New GeoPoint(59.9398, 30.3146)
      pushpin2.Tag = New ItemInfo With {
          .IsOpened = False
      }
      storage.Items.Add(pushpin2)
  End Sub

  Private Sub Storage_DataChanged(ByVal sender As Object, ByVal e As DataAdapterChangedEventArgs)
      For Each item As MapItem In vectorLayer.Data.Items
          Dim info As ItemInfo = TryCast(item.Tag, ItemInfo)
          item.Visible = info.IsOpened
      Next
  End Sub

  Public Class ItemInfo
      Public Property IsOpened As Boolean
  End Class

Related GitHub Examples

The following code snippet (auto-collected from DevExpress Examples) contains a reference to the Tag property.

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.

C#

winforms-dashboard-custom-items-extension/CS/CustomItemExtension/CustomItems/WaypointMap/WaypointMapItemControlProvider.cs#L61

IList<DashboardFlatDataSourceRow> selectedRows = selection.GetDashboardFlatDataSourceRows(flatData);
var selectedLines = mapItemStorage.Items.Where(item => selectedRows.Contains(item.Tag));
vectorLayer.SelectedItems.AddRange(selectedLines.ToList());

VB.NET

winforms-dashboard-custom-items-extension/VB/CustomItemExtension/CustomItems/WaypointMap/WaypointMapItemControlProvider.vb#L72

Dim selectedRows As IList(Of DashboardFlatDataSourceRow) = selection.GetDashboardFlatDataSourceRows(flatData)
Dim selectedLines = mapItemStorage.Items.Where(Function(item) selectedRows.Contains(item.Tag))
vectorLayer.SelectedItems.AddRange(selectedLines.ToList())