我在 asp.net 中实现谷歌地图 api 时遇到问题。这是我的aspx代码:
<%@ Page Title="" Language="C#" AutoEventWireup="true" CodeFile="visual_loc.aspx.cs" Inherits="visual_loc" %>
<%--A sample project by Ghaffar khan--%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>Your Data on Google Map </title>
<%--Google API reference--%>
<script src="http://maps.google.com/maps?file=api&v=2&sensor=false
&key=asdfg" type="text/javascript">
</script>
</head>
<body onload="initialize()" onunload="GUnload()">
<form id="form1" runat="server">
<asp:Panel ID="Panel1" runat="server">
<%--Place holder to fill with javascript by server side code--%>
<asp:Literal ID="js" runat="server"></asp:Literal>
<%--Place for google to show your MAP--%>
<div ID="map_canvas" style="width: 100%; height: 728px; margin-bottom: 2px;">
</div>
<br />
</asp:Panel>
<br />
</form>
</body>
</html>
而我背后的代码:
getLocation()
是从我的数据库中获取经度和纬度的方法。是从这些位置createDataTable()
创建的方法。DataTable
protected void Page_Load(object sender, EventArgs e)
{
string user_id;
user_id = Request.Cookies["cookie"]["Login"];
getLocation(user_id);
BuildScript( createDataTable());
}
private void BuildScript(DataTable tbl)
{
String Locations = "";
foreach (DataRow r in tbl.Rows)
{
// bypass empty rows
if (r["Latitude"].ToString().Trim().Length == 0)
continue;
string Latitude = r["Latitude"].ToString();
string Longitude = r["Longitude"].ToString();
// create a line of JavaScript for marker on map for this record
Locations += Environment.NewLine + " map.addOverlay(new GMarker(new GLatLng(" + Latitude + "," + Longitude + ")));";
}
// construct the final script
js.Text = @"<script type='text/javascript'>
function initialize() {
if (GBrowserIsCompatible()) {
var map = new GMap2(document.getElementById('map_canvas'));
map.setCenter(new GLatLng(52.259, 21.012), 2);
" + Locations + @"
map.setUIToDefault();
}
}
</script> ";
}
整个操作导致显示没有内容的空站点。我究竟做错了什么?