Scrolling

• Jan 23, 2019
• 3 minutes to read

End users can navigate a map using the Map control’s scrolling capabilities.

• Overview
• Circular Scrolling
• How End Users Can Scroll a Map

Overview

Scrolling is enabled in the Map Control by default. Set the MapControl.EnableScrolling property to false to disable scrolling.

Use the MiniMap.EnableScrolling property to manage scrolling on a mini-map. Refer to the Mini Map topic to learn more about mini-maps.

Circular Scrolling

The Map Control allows you to scroll a map horizontally infinitely. Use the GeoMapCoordinateSystem.CircularScrollingMode property to set the appropriate circular scrolling mode.

The following code shows how to allow end users to endlessly scroll an image tile and vector items’ layers:

C#

mapControl.CoordinateSystem = new GeoMapCoordinateSystem() {
    CircularScrollingMode = CircularScrollingMode.TilesAndVectorItems
};

VB.NET

Private Shadows Sub GeoMapCoordinateSystem()
    CircularScrollingMode = CircularScrollingMode.TilesAndVectorItems
End Sub

The table below lists classes and properties which the code uses:

Class or Property	Description
MapControl.CoordinateSystem	Specifies a map’s coordinate system.
GeoMapCoordinateSystem	The geographical coordinate system.
CircularScrollingMode	Lists modes that specify the Circular Scrolling behavior.

Note

Note the following points before using Circular Scrolling:

• The map should have a geographical coordinate system;
• Circular Scrolling does not work with Web Map Service Provider.

Note that, a map shape should fulfill the following condition to cross the 180th meridian: one or several points’ longitudes should exceed the 180 (-180) limit:

C#

MapPolygon polygon = new MapPolygon();
polygon.Points.Add(new GeoPoint(10, -170));
polygon.Points.Add(new GeoPoint(10, 170));
polygon.Points.Add(new GeoPoint(-10, 170));
polygon.Points.Add(new GeoPoint(-10, -170));
vectorItemStorage.Items.Add(polygon);

// Point longitudes enclose the 180 meridian.
MapPolygon polygonCross180 = New MapPolygon();
polygonCross180.Fill = Color.Orange;
polygonCross180.Points.Add(new GeoPoint(30, 190));
polygonCross180.Points.Add(new GeoPoint(30, 170));
polygonCross180.Points.Add(new GeoPoint(20, 170));
polygonCross180.Points.Add(new GeoPoint(20, 190));
vectorItemStorage.Items.Add(polygon180);

VB.NET

Dim polygon = New MapPolygon
polygon.Points.Add(New GeoPoint(10, -170))
polygon.Points.Add(New GeoPoint(10, 170))
polygon.Points.Add(New GeoPoint(-10, 170))
polygon.Points.Add(New GeoPoint(-10, -170))
vectorItemStorage.Items.Add(polygon)

' Point longitudes enclose the 180 meridian.
Dim polygonCross180 = New MapPolygon
polygonCross180.Fill = Color.Orange
polygonCross180.Points.Add(New GeoPoint(30, 190))
polygonCross180.Points.Add(New GeoPoint(30, 170))
polygonCross180.Points.Add(New GeoPoint(20, 170))
polygonCross180.Points.Add(New GeoPoint(20, 190))
vectorItemStorage.Items.Add(polygonCross180)

The code above produces the following image:

How End Users Can Scroll a Map

An end user can scroll a map as follows:

Action	Effect
Hold down the left mouse button and drag it	Move the mouse pointer while holding down the left mouse button. The mouse pointer changes from to when an end user holds down the left mouse button. The map is scrolled in the same direction as the mouse pointer’s movement.
Use the arrows on the map navigation panel.	An end user can scroll a map in four directions by clicking the arrows on the map navigation panel. For example, use the right arrow in the navigation panel to scroll to the east. Use the NavigationPanelOptions.ShowScrollButtons property to manage scroll buttons’ visibility in the navigation panel.
Use the “Arrow” keys (Left, Up, Right or Down).	Press the Left arrow key to scroll the map west. Press the Up arrow key to scroll the map north. Press the Right arrow key to scroll the map east. Press the Down arrow key to scroll the map south.
Use flick gestures on touchscreen devices.	An end user can scroll a map using flick gestures on a touchscreen device.