Question

I’m creating a Google Maps partial view/user control in my project that is passed a strongly typed list of objects containing latitude and longitude values.

Currently, this is the code I have for the partial:

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<IEnumerable<Project.Models.Entities.Location>>" %>
<!-- Place for google to put the map -->
<div id="report_map_canvas" style="width: 100%; height: 728px; margin-bottom: 2px;">
</div>

<script type='text/javascript'>    
google.load("maps", "2");
$(document).ready(initializeMap);

function initializeMap() {
    if (GBrowserIsCompatible()) {
        var map = new GMap2(document.getElementById('report_map_canvas'));
        map.setCenter(new GLatLng(51.5, -0.1167), 2);
        <% foreach (var item in Model) { %>
        map.addOverlay(new GMarker(new GLatLng('<%= Html.Encode(item.latitude)%>','<%= Html.Encode(item.longitude)%>'),{ title: '<%= Html.Encode(String.Format("{0:F}",item.speed)) %> km/h '}));
        <% } %>
        map.setUIToDefault();
    }
}
</script>

Is it right to dynamically create the javascript file this way by looping over the list and emitting javascript?

Is there a better way to do it?

Answer 1

i don’t prefer this way because if you have many items to add you will make a big document to load for the user. instead I prefer to load the items as JSON and then iterate them and use google functions, eg:

var data = [<%="{x:50.44444,y:30.44444,speed:50},..."  %>] // generate you JSON Here as array

for(var i = 0; i < data.length; i++){
map.addOverlay(new GMarker(new GLatLng(data[i].y,data[i].x),{ title: data[i].speed + 'Km/h'}));
}

so you will not repeat this part

 map.addOverlay(new GMarker(new GLatLng(,),{ title:  + 'Km/h'}));

which will increase the document size and page load