Adding labels to ESRI maps

[James]

What's the best way to go about adding labels (counties within a state, specifically in my case) to one of the state SHP/DBF examples from the drill down demo? Is it done in the SHP file or can I do it from the DBF data?

Thanks in advance!

[Andrey]

Hi James,

You can add labels as TextBlock objects from code in the CountyLayerReaderReadCompleted method of the example which is called after the shape file with counties is read. In this case each read shape contains the name of the county in its extended data from DBF. Unfortunately the example data files do not contain coordinates for best label positions, but for the most part it will be correct to use the center of county.
The sample code is the following:

private void CountyLayerReaderReadCompleted(object sender, ReadShapesCompletedEventArgs eventArgs)

{

    if (eventArgs.Error != null)

        return;


    this.LabelLayer.Items.Clear();


    HotSpot hotSpot = new HotSpot();

    hotSpot.X = 0.5;

    hotSpot.Y = 0.5;


    foreach (MapShape shape in this.CountyLayer.Items)

    {

        shape.MouseLeftButtonUp += this.CountyShapeMouseLeftButtonUp;


        string name = (string)shape.ExtendedData.GetValue(CountyExtendedPropertyName);

        TextBlock label = new TextBlock();

        point.Text = name;


        MapLayer.SetLocation(label, shape.GeographicalBounds.Center);

        MapLayer.SetHotSpot(label, hotSpot);


        this.LabelLayer.Items.Add(label);

    }


    this.BringIntoView(this.stateShape);

}

The example uses additional "LabelLayer" layer for labels rendering. You should also add it to the RadMap.

<telerik:RadMap x:Name="RadMap1"
            Background="#D9E1FF"
            BorderBrush="Black"
            BorderThickness="1"
            UseDefaultLayout="False"
            MouseClickMode="None"
            MouseDoubleClickMode="None"
            ZoomLevel="4"
            Center="36.8174363084084, -97.3212482126264">
    <telerik:RadMap.Provider>
        <telerik:EmptyProvider MinZoomLevel="4" MaxZoomLevel="8" />
    </telerik:RadMap.Provider>
    <telerik:InformationLayer x:Name="StateLayer">
        <telerik:InformationLayer.ShapeFill>
            <telerik:MapShapeFill Fill="#FFF0D9" Stroke="#B1946D" StrokeThickness="1" />
        </telerik:InformationLayer.ShapeFill>
        <telerik:InformationLayer.HighlightFill>
            <telerik:MapShapeFill Fill="#FFEEA6" Stroke="#B1946D" StrokeThickness="1" />
        </telerik:InformationLayer.HighlightFill>
    </telerik:InformationLayer>
    <telerik:InformationLayer x:Name="CountyLayer">
        <telerik:InformationLayer.ShapeFill>
            <telerik:MapShapeFill Fill="#FFDBA3" Stroke="#B1946D" StrokeThickness="1" />
        </telerik:InformationLayer.ShapeFill>
        <telerik:InformationLayer.HighlightFill>
            <telerik:MapShapeFill Fill="#FFEEA6" Stroke="#B1946D" StrokeThickness="1" />
        </telerik:InformationLayer.HighlightFill>
    </telerik:InformationLayer>
    <telerik:InformationLayer x:Name="LabelLayer" />
</telerik:RadMap>

Regards,
Andrey Murzov
the Telerik team

[James]

Thanks very much. You are right that it does not end up looking ideal. I saw that coming. Still, nice to know how to hook into the loading of each shape in the layer. Very nice.

[Andrey]

Hi James,

The map control does not contain an event which occurs after the item is added to the information layer. If you provide us with more details about things you try to implement, then we can help you to choose another way to do it.

Kind regards,
Andrey Murzov
the Telerik team