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Hi Team

I have debug my code, i am experience this issue Uncaught syntax error. Kindly please help me to resolve this issue maybe i could be missing some javascript library, please advice me and help mates.

What I have tried:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Data.SqlClient;
using System.Configuration;

namespace eNtsaRegistrationTraining.Controllers
    public class MapsController : Controller
        // GET: Maps
        public ActionResult GoogleMaps()
            string markers = "[";
            string conString = ConfigurationManager.ConnectionStrings["eNtsaRegistration"].ConnectionString;
            SqlCommand cmd = new SqlCommand("SELECT * FROM dbo.Locations");
            using (SqlConnection con = new SqlConnection(conString))
                cmd.Connection = con;
                using(SqlDataReader sdr = cmd.ExecuteReader())
                        markers += "{";
                        markers += string.Format("'title': '{0}',", sdr["Name"]);
                        markers += string.Format("'lat:' '{0}',", sdr["Latitute"]);
                        markers += string.Format(" 'lng': '{0}',", sdr["Longitute"]);
                        markers += string.Format("'description': '{0}'", sdr["Description"]);
                        markers += "},";

            markers += "];";
            ViewBag.Makers = markers;

            return View();

    ViewBag.Title = "GoogleMaps";
    Layout = null;

<pre lang="Javascript"><!DOCYTPE html>
    <meta name="viewport" content="width=device-width"/>
    <title>eNtsa Office Location</title>
    <div id="dvMap" style="width: 500px; height: 500px">
    <script type="text/javascript" src=""></script>
    <script type="text/javascript">
        var markers = @Html.Raw(ViewBag.Markers);
        window.onload = function () {
            var mapOptions = {
                center: new google.maps.LatLng(markers[0].lat, markers[0].lng),
                zoom: 8,
                mapTypeId: google.maps.MapTypeId.ROADMAP
            var infoWindow = new google.maps.InfoWindow();
            var map = new google.maps.Map(document.getElementById("dvMap"), mapOptions);
            for (i = 0; i < markers.length; i++) {
                var data = markers[i]
                var myLatlng = new google.maps.LatLng(, data.lng);
                var marker = new google.maps.Marker({
                    position: myLatlng,
                    map: map,
                    title: data.title
                (function (marker, data) {
                    google.maps.event.addListener(marker, "click", function (e) {
              , marker);
                })(marker, data);

Updated 10-Mar-20 2:03am
Richard MacCutchan 10-Mar-20 5:23am    
Where does the error occur?
gcogco10 10-Mar-20 5:24am    
var markers = @Html.Raw(ViewBag.Markers);
Jon McKee 10-Mar-20 5:40am    
What does ViewBag.Markers contain? It looks like it's an array, in which case I'm pretty sure you don't need @Html.Raw() because all that does is prevent the default Razor encoding for strings from happening by wrapping the non-encoded string in an IHtmlString. I'm actually not sure what happens if you pass it a non-string.
gcogco10 10-Mar-20 5:44am    
I omit to put the logic for my Controller, I invoke using Marker from the controller, that variable is accessing those fields as being declared by the controller.

ViewBag.Makers = markers;

That might be your issue. Makers should be Markers. So your javascript is probably rendering like var markers = ; causing a syntax error.
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gcogco10 10-Mar-20 6:08am    
Thanks Jon, now i am getting this Uncaught TypeError: Cannot read property 'lat' of undefined
at window.onload (GoogleMaps:19) center: new google.maps.LatLng(markers[0].lat, markers[0].lng), The name i defined there within the controller. Please advice
Jon McKee 10-Mar-20 6:11am    
"'lat:' '{0}'," should be "'lat': '{0}',". The single quote is in the wrong spot.

I also notice that the way you're concatenating the objects, you will end up with an extra ',' at the end. Ex: [ { .... }, { .... },]. So you might need to delete that last character before doing markers +="];".

Something like this should work:
let commaIndex = markers.lastIndexOf(",");
if (commaIndex > 0) {
  markers = markers.substring(0, commaIndex);
gcogco10 10-Mar-20 6:24am    
Thanks mate, i removed the dbo.Locations to be actually Table name 'Locations' only. Now my maps dont load well and dont know why. please assist
Jon McKee 10-Mar-20 6:29am    
Is it a single-schema database? If it worked with the schema there why remove it? Never hurts to be specific even if there is only one schema.
gcogco10 10-Mar-20 6:33am    
Its a single schema database
Don't try to build a JSON string manually. Instead, build a collection of objects, and then use a proper JSON serializer to generate the JSON.

public class Marker
    public string title { get; set; }
    public double lat { get; set; }
    public double lng { get; set; }
    public string description { get; set; }
public ActionResult GoogleMaps()
    var markers = new List<Marker>();
    string conString = ConfigurationManager.ConnectionStrings["eNtsaRegistration"].ConnectionString;
    using (var con = new SqlConnection(conString))
    using (var cmd = new SqlCommand("SELECT Name, Latitude, Longitude, Description FROM dbo.Locations", con))
        using (var sdr = cmd.ExecuteReader(CommandBehavior.CloseConnection))
            while (sdr.Read())
                markers.Add(new Marker
                    title = Convert.ToString(sdr["Name"]),
                    lat = Convert.ToDouble(sdr["Latitude"]),
                    lng = Convert.ToDouble(sdr["Longitude"]),
                    description = Convert.ToString(sdr["Description"]),

    ViewBag.Markers = markers;
    return View();
var markers = @Html.Raw(Json.Encode(ViewBag.Markers));
Share this answer
gcogco10 10-Mar-20 8:20am    
Thanks Richard, the challenge i am getting now. This app is not showing my current location within the map. What could i be missing, the location its pointing outside continent(Africa). It should be point to SA(port elizabeth)
Richard Deeming 10-Mar-20 8:28am    
There must be something wrong with your coordinates. I suspect you've got the wrong sign on your latitude - Google expects the degrees North, so you'll need to use -33.9608.
gcogco10 10-Mar-20 8:56am    
OK noted, but i have amended using this logic above. I am getting this error center: new google.maps.LatLng(markers[0].lat, markers[0].lng),
zoom: 8,Uncaught TypeError: Cannot read property '0' of null
Richard Deeming 10-Mar-20 8:59am    
Well that error sounds like you're not actually outputting any markers. You did correct the spelling from Makers to Markers as Jon pointed out, didn't you?

Have a look at the source of the page from your browser to see what the markers variable is set to.

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