使用谷歌地图API发布位置标记

本文关键字：位置 布位置 谷歌地图 API | 更新日期: 2023-09-27 18:20:06

我正在使用Google Maps API来显示.Net平台上的位置标记。我已经将纬度、经度、城市和州的信息存储在数据库中，如果我添加纬度和经度的第7个数据库条目，地图和标记将无法显示。

下面是.aspx的代码和背后的代码

.aspx：

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
     <title>
         Google Map Locations
     </title>
     <script type="text/javascript"
     src="https://maps.googleapis.com/maps/api/js?key=My_Key&sensor=false">
     </script>
</head>
<body onload="initialize()">
     <form id="form1" runat="server">
          <div id="mapArea" style="width: 700px; height: 700px;">
          </div>
           <asp:Label ID="Label11" runat="server"></asp:Label>
     </form>
</body>
</html>

代码隐藏：

namespace GoogleMaps
{
    public partial class GoogleMaps : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            string markers = GetLocationMarkers();
            Label1.Text = @"
              <script type='text/javascript'>
                 function initialize() {
                 var mapOptions = {
                     center: new google.maps.LatLng(39.948427, -101.836428),
                     zoom: 2,
                     mapTypeId: google.maps.MapTypeId.ROADMAP
                 };
                 var myMap = new google.maps.Map(document.getElementById('mapArea'),
                             mapOptions);"
                  + markers +
                @"}
             </script>";
        }
        protected string GetLocationMarkers()
        {
            string markers = "";
            using (SqlConnection con = new
            SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["ConString"].ConnectionString))
            {
                SqlCommand cmd = new SqlCommand(
                                 "SELECT Latitude, Longitude, City FROM Map", con);
                con.Open();
                SqlDataReader reader = cmd.ExecuteReader();
                int i = 0;
                while (reader.Read())
                {
                    i++;
                    markers += @"var marker"+i.ToString()+ @" = 
                               new google.maps.Marker({                                                                                                            
                    position:google.maps.LatLng("+reader["Latitude"].ToString() +"
                    , "+
                    reader["Longitude"].ToString() +")," + 
                    @"map: myMap,title:'"+reader["City"].ToString()+
                   "'});";
                }
            }
            return markers;
        }
    }
}

在调试时，我发现，在Marker 7上，我看到''r''n在城市名称之后，在下面的调试输出中，示例：在Pipestone 之后

markers "var marker1 = new google.maps.Marker({
      position: new google.maps.LatLng(32.692383, -114.626648),
      map: myMap, title:'Yuma'});
var marker2 = new google.maps.Marker({
      position: new google.maps.LatLng(38.250095, -122.040001),
      map: myMap, title:'Fairfield'});
var marker3 = new google.maps.Marker({
      position: new google.maps.LatLng(26.56225, -81.948121),
      map: myMap, title:'Cape Coral'});
var marker4 = new google.maps.Marker({
      position: new google.maps.LatLng(45.52263, -122.681208),
      map: myMap, title:'Portland'});
var marker5 = new google.maps.Marker({
      position: new google.maps.LatLng(37.810308, -85.981012),
      map: myMap, title:'Vine Grove'});
var marker6 = new google.maps.Marker({
      position: new google.maps.LatLng(28.540228, -81.385238),
      map: myMap, title:'Orlando'});
var marker7 = new google.maps.Marker({
      position: new google.maps.LatLng(43.99878, -96.313606),
      map: myMap, title:'Pipestone'r'n'});" string

但是当数据库中只有6个条目在城市名称后我看不到时，例如：在下面的调试输出中：在Orlando 之后

markers "var marker1 = new google.maps.Marker({
      position: new google.maps.LatLng(32.692383, -114.626648),
      map: myMap, title:'Yuma'});
var marker2 = new google.maps.Marker({
      position: new google.maps.LatLng(38.250095, -122.040001),
      map: myMap, title:'Fairfield'});
var marker3 = new google.maps.Marker({
      position: new google.maps.LatLng(26.56225, -81.948121),
      map: myMap, title:'Cape Coral'});
var marker4 = new google.maps.Marker({
      position: new google.maps.LatLng(45.52263, -122.681208),
      map: myMap, title:'Portland'});
var marker5 = new google.maps.Marker({
      position: new google.maps.LatLng(37.810308, -85.981012),
      map: myMap, title:'Vine Grove'});
var marker6 = new google.maps.Marker({
      position: new google.maps.LatLng(28.540228, -81.385238),
      map: myMap, title:'Orlando'});

是什么原因导致谷歌地图没有出现？数据库中只有6个条目，显示带有标记的地图并没有问题。任何答复都将不胜感激。

使用谷歌地图API发布位置标记

可能是转义序列问题尝试仅选择第7个城市Piperstone以检查问题是否与字符串内容有关。在此标记中，si不显示，尝试更新此条目，删除"''r''n"字符

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