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Client-side

This article explains how to data bind Shape and Marker layers of a RadMap control to a client-side data source.

Getting Started with Client-side Data Binding

The Shape and Marker layers are created by using different Map Layers in the RadMap's LayersCollection. They must have the proper Type property (Shape or Marker) set.

Data binding the MapLayer can be achieved by using:

  • a RadClientDataSource control by setting its ID to the MapLayer’s ClientDataSourceID property. You can examine Example 1 and Example 3 or a live example demonstrating client-side data binding of shapes and markers is available in the Client-side Data Binding demo;

  • the client-side OnInitialize event to set a JSON literal array to the appropriate options of the RadMap. You can examine Example 2 and Example 4.

Data Binding a Shape Layer

Binding a Shape layer requires using data built according to the GeoJSON specifications. The RadMap provides an out of the box functionality to render the shapes on the layer according to the provided data.Example 1 demonstrates how to use a RadClientDataSource control to get the needed data and Example 2 shows how you can use a simple array that you already have available.

To use the RadClientDataSource control for data binding you should configure it to request the appropriate data. It is important to set its ServiceType property to GeoJSON. Setting the RadClientDataSource server ID to the ClientDataSourceID property of the MapLayer is enough to configure the layer data binding. Optionally, you can further modify the shape appearance via the ShapeSettings property of the LayerDefaultsSettings tag.

In Example 1 you can examine how the Shape layer is bound to a .json file. The used file is provided in the Shapes Layer demo of the RadMap.

Example 1: Using RadClientDataSource control to bind a Shape layer.

<telerik:RadClientDataSource runat="server" ID="RadClientDataSource1">
      <DataSource>
           <WebServiceDataSourceSettings ServiceType="GeoJSON">
                <Select Url="http://demos.telerik.com/aspnet-ajax/map/examples/functionality/shapes-layer/Content/countries.json" DataType="JSON" />
           </WebServiceDataSourceSettings>
      </DataSource>
 </telerik:RadClientDataSource>

<telerik:RadMap RenderMode="Lightweight" runat="server" ID="RadMap1" Zoom="3" Width="940" Height="500">
    <LayersCollection>
            <telerik:MapLayer Type="Shape" ClientDataSourceID="RadClientDataSource1">
            </telerik:MapLayer>
    </LayersCollection>
</telerik:RadMap>

In Example 2 you can see how to use a simple data binding approach with an array as a data source.

Example 2: Using the OnInitialize event to bind Shape layer to an array of JSON literals.

<script type="text/javascript">
    var shapeData = [{
        "type": "Polygon",
        "coordinates": [
            [[30, 10], [40, 40], [20, 40], [10, 20], [30, 10]]
        ]
    }];


    function OnInitialize(sender, args) {
        var originalOptions = args.get_options();

        originalOptions.layers[0].dataSource = { data: shapeData };

        args.set_options(originalOptions);
    }
</script>

<telerik:RadMap RenderMode="Lightweight" runat="server" ID="RadMap1" Zoom="2" Width="500" Height="200"> 
    <ClientEvents OnInitialize="OnInitialize" />
    <CenterSettings Latitude="30" Longitude="10" />
    <LayerDefaultsSettings>
        <ShapeSettings>
            <StyleSettings>
                <FillSettings Color="green" />
                <StrokeSettings Color="black" Width="2" />
            </StyleSettings>
        </ShapeSettings>
    </LayerDefaultsSettings>
    <LayersCollection>
        <telerik:MapLayer Type="Shape">
        </telerik:MapLayer>
    </LayersCollection>
</telerik:RadMap>

Data Binding a Marker Layer

To bind a Marker layer to a RadClientDataSource you need to set its ID to the MapLayer's ClientDataSourceID property and use the LocationField attribute to specify the data field that represents the latitude and longitude position of the marker. The location must be an array of numbers in the format - [ latitude, longitude ]. You can see this approach in Example 3. You can find the used .json file in theMarkers live demo.

Example 3: Using RadClientDataSource control to bind a Marker layer.

<telerik:RadClientDataSource runat="server" ID="RadClientDataSource1">
    <DataSource>
        <WebServiceDataSourceSettings>
            <Select DataType="JSON" Url="http://demos.telerik.com/aspnet-ajax/map/examples/functionality/markers/JSON/MarkersData.json" />
        </WebServiceDataSourceSettings>
    </DataSource>
</telerik:RadClientDataSource>

<telerik:RadMap RenderMode="Lightweight" runat="server" ID="RadMap1" Zoom="2" Width="940" Height="500">
    <CenterSettings Latitude="23" Longitude="10" />
    <LayersCollection>
        <telerik:MapLayer Type="Tile" Subdomains="a,b,c"
                UrlTemplate="http://#= subdomain #.tile.openstreetmap.org/#= zoom #/#= x #/#= y #.png"
                Attribution="&copy; <a href='http://osm.org/copyright' title='OpenStreetMap contributors' target='_blank'>OpenStreetMap contributors</a>.">
        </telerik:MapLayer>
        <telerik:MapLayer Type="Marker" Shape="PinTarget" ClientDataSourceID="RadClientDataSource1" LocationField="location">
        </telerik:MapLayer>
    </LayersCollection>
</telerik:RadMap>

In Example 4 you can see how to use simple data binding with a Marker layer.

Example 4: Using the OnInitialize event to bind Marker layer to an array of JSON literals.

<script type="text/javascript">
    var markerData = [{
        "location": [51.506421, -0.127215],
        "city": "London"
    }, {
        "location": [51.762152, -1.258430],
        "city": "Oxford"
    }];


    function OnInitialize(sender, args) {
        var originalOptions = args.get_options();

        originalOptions.layers[1].dataSource = { data: markerData };

        args.set_options(originalOptions);
    }
</script>

<telerik:RadMap RenderMode="Lightweight" runat="server" ID="RadMap1" Zoom="7" Width="500" Height="200">
    <ClientEvents OnInitialize="OnInitialize"/> 
    <CenterSettings Latitude="51.506421" Longitude="-0.127215" />
    <LayersCollection>
        <telerik:MapLayer Type="Tile" Subdomains="a,b,c"
            UrlTemplate="http://#= subdomain #.tile2.opencyclemap.org/transport/#= zoom #/#= x #/#= y #.png"
            Attribution="&copy; <a href='http://osm.org/copyright' title='OpenStreetMap contributors' target='_blank'>OpenStreetMap contributors</a>.">
        </telerik:MapLayer>
        <telerik:MapLayer type="Marker" Shape="pinTarget">
            <TooltipSettings AutoHide="false" Template="#= marker.dataItem.city # <br/> #=  location.lat #, #=  location.lng #"></TooltipSettings>
        </telerik:MapLayer>
    </LayersCollection>
</telerik:RadMap>

See Also