這兩天在做地圖這塊，一點點js代碼，各種坑。第一次接觸js，各種難，下面就這幾天的研究做一些總結，求坑
在事件監聽器中使用閉包
在執行事件監聽器時，通常可取的做法是將私有數據和持久性數據附加到對像中。 JavaScript 不支持“私有”實例數據，但是支持允許內部函數訪問外部變量的閉包。在事件監聽器中，閉包非常適用於訪問通常不附加到發生事件的對象的變量。
以下示例在事件監聽器中使用了函數閉包將加密訊息分配給一組標記。點擊每個標記將會看到加密訊息的一部分，該訊息並不包含在標記本身內。
複製代碼代碼如下:
var map;
function initialize() {
var myLatlng = new google.maps.LatLng(-25.363882,131.044922);
var mapOptions = {
zoom: 4,
center: myLatlng,
mapTypeId: google.maps.MapTypeId.ROADMAP
}
map = new google.maps.Map(document.getElementById("map_canvas"), mapOptions);
// Add 5 markers to the map at random locations.
var southWest = new google.maps.LatLng(-31.203405,125.244141);
var northEast = new google.maps.LatLng(-25.363882,131.044922);
var bounds = new google.maps.LatLngBounds(southWest,northEast);
map.fitBounds(bounds);
var lngSpan = northEast.lng() - southWest.lng();
var latSpan = northEast.lat() - southWest.lat();
for (var i = 0; i < 5; i++) {
var location = new google.maps.LatLng(southWest.lat() + latSpan * Math.random(),
southWest.lng() + lngSpan * Math.random());
var marker = new google.maps.Marker({
position: location,
map: map
});
var j = i + 1;
marker.setTitle(j.toString());
attachSecretMessage(marker, i);
}
}
// The five markers show a secret message when clicked
// but that message is not within the marker's instance data.
function attachSecretMessage(marker, number) {
var message = ["This","is","the","secret","message"];
var infowindow = new google.maps.InfoWindow(
{ content: message[number],
size: new google.maps.Size(50,50)
});
google.maps.event.addListener(marker, 'click', function() {
infowindow.open(map,marker);
});
}
這段代碼是從google官方裡面複製下來的
接下來我要實現從數據庫中讀取經緯度、地址信息，在google map上進行標註並單擊標註出現信息
要實現多點標註，以上代碼可以參考
複製代碼代碼如下:
<script type="text/javascript" >
var map;
window.onload =function load() {
var number='<%=number %>';//獲取後台cs的pubilc的number的值
var address = new Array()
var weidu=new Array();
var jingdu=new Array();
var chepai = new Array();
<% for(int i=0;i<number;i++){ %>
weidu.push('<%=lan[i]%>');//從後台cs獲取經緯度的值
jingdu.push('<%=lon[i]%>');
address.push('<%=addr[i]%>');
chepai.push('<%=carnum[i] %>');
// var wei ;
// wei = chepai['<%=i%>'];
// alert(wei);
<% } %>
var Latlng = new google.maps.LatLng(weidu[0], jingdu[0]);
// var myLatlng = new google.maps.LatLng(25.273566, 110.290195);
var myOptions = {
zoom: 8,
center: Latlng,
mapTypeId: google.maps.MapTypeId.ROADMAP
};
map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);////初始化一個地圖實例
for(var j=0;j<number;j++) //這里卡了好久，原因是js的類型只有var；把js和cs弄混了一直用到《% %>，其實單純的js不需要，跟C差不多就可以了
{
var lat = weidu[j];
var lng = jingdu[j];
var addre = address[j];
var chepaihao = chepai[j];
// alert(j);
// alert(lat);
// var image = 'Image/webcam.png';
//設置標誌點
var myLatlng = new google.maps.LatLng(weidu[j ], jingdu[j ]);
var h = chepaihao;
var tit = h.toString();
var marker = new google.maps.Marker({
position: myLatlng,
map: map,
// icon: "http://google-maps-icons.googlecode.com/files/yellow08.png",
// icon: image, //通過icon可以設定自己想顯示的圖標，不設置則顯示Google map默認的圖標
title: tit //title表示鼠標放到marker上要顯示的值。
});
attachSecretMessage(marker, j,addre,lat,lng);
}
}
function attachSecretMessage(marker, number,addre1,lat1,lng1) {
// var message = ["This", "is", "the", "secret", "message"];
var infowindow = new google.maps.InfoWindow(
{ content: "<span style='font-size:15px'><b>地址: </b>" + addre1 + "<br>"+ "經緯度："+ lat1 + "，"+ lng1 +"</span>",
size: new google.maps.Size(50, 50)
});
// infowindow.setContent("地址:"+ addre1 +"經度:" +lat1 + "緯度："+lng1);
//點擊彈出信息窗口
google.maps.event.addListener(marker, 'click', function () {
infowindow.open(map, marker);
});
}
</script>
cs後端代碼：
複製代碼代碼如下:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
public partial class Default2 : System.Web.UI.Page
{
public double[] la = new double[25];
public double[] ln = new double[25];
public int[] id = new int[25];
public string[] addr = new string[25];
public int number;
protected void Page_Load(object sender, EventArgs e)
{
string mycnnConnectionString1 = System.Configuration.ConfigurationManager.ConnectionStrings["testconect"].ConnectionString; //創建連接字符串
SqlConnection mycnn1 = new SqlConnection(mycnnConnectionString1);
mycnn1.Open();
SqlCommand cmd1 = new SqlCommand("select L_ID,L_Lantitude,L_Longitude,L_Address from LatestPosition ", mycnn1);
SqlDataReader dr1 = cmd1.ExecuteReader();
int k2 = 0;
int k3 = 0;
int k4 = 0;
int k1 = 0;
// string buf1 = "";
double buf2 = 0;
double buf3 = 0;
int buf4 = 0;
string buf1 = "0";
while (dr1.Read())
{
//lat
buf2 = (double)dr1["L_Lantitude"];
la[k2] = buf2;
k2++;
//lng
buf3 = (double)dr1["L_Longitude"];///數據庫讀取float型的數據要用double
ln[k3] = buf3;
k3++;
//id
buf4 = (int)dr1["L_ID"];
id[k4] = buf4;
k4++;
buf1 = dr1["L_Address"].ToString();
addr[k1] = buf1;
k1++;
}
number = k4;
dr1.Close();
mycnn1.Close();
}
}