In this article, I will explain how to show or add multiple markers to Google maps from database in asp.net website using JavaScript or JavaScript Show multiple markers in Google maps using database in asp.net.
First you need create a new table in your database like as shown below:
Now write the following code in your aspx to show multiple markers in Google map from database like as shown below:
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
After that write the following code in code behind
// This method is used to convert datatable to json string
public string ConvertDataTabletoString()
{
DataTable dt = new DataTable();
using (SqlConnection con = new SqlConnection("Data Source=localhost;Initial Catalog=positionmaster;Integrated Security=true"))
{
using (SqlCommand cmd = new SqlCommand("select title=PlaceName,lat=PlaceLatitude,lng=PlaceLongitude,PlaceDescription from LocationDetails", con))
{
con.Open();
SqlDataAdapter da = new SqlDataAdapter(cmd);
da.Fill(dt);
System.Web.Script.Serialization.JavaScriptSerializer serializer = new System.Web.Script.Serialization.JavaScriptSerializer();
List<Dictionary<string, object>> rows = new List<Dictionary<string, object>>();
Dictionary<string, object> row;
foreach (DataRow dr in dt.Rows)
{
row = new Dictionary<string, object>();
foreach (DataColumn col in dt.Columns)
{
row.Add(col.ColumnName, dr[col]);
}
rows.Add(row);
}
return serializer.Serialize(rows);
}
}
}
VB.NET Code
Imports System.Collections.Generic
Imports System.Data
Imports System.Data.SqlClient
Partial Class Default3
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
End Sub
' This method is used to convert datatable to json string
Public Function ConvertDataTabletoString() As String
Dim dt As New DataTable()
Using con As New SqlConnection("Data Source=localhost;Initial Catalog=positionmaster;Integrated Security=true")
Using cmd As New SqlCommand("select title=PlaceName,lat=PlaceLatitude,lng=PlaceLongitude,PlaceDescription from LocationDetails", con)
con.Open()
Dim da As New SqlDataAdapter(cmd)
da.Fill(dt)
Dim serializer As New System.Web.Script.Serialization.JavaScriptSerializer()
Dim rows As New List(Of Dictionary(Of String, Object))()
Dim row As Dictionary(Of String, Object)
For Each dr As DataRow In dt.Rows
row = New Dictionary(Of String, Object)()
For Each col As DataColumn In dt.Columns
row.Add(col.ColumnName, dr(col))
Next
rows.Add(row)
Next
Return serializer.Serialize(rows)
End Using
End Using
End Function
End Class
First you need create a new table in your database like as shown below:
Column Name
|
Data Type
|
Allow Nulls
|
PlaceID
|
int(set isidentity
property=true)
|
No
|
PlaceName
|
varchar(50)
|
Yes
|
PlaceLatitude
|
numeric(12,6)
|
Yes
|
PlaceLongitude
|
numeric(12,6)
|
Yes
|
PlaceDescription
|
Varchar(250)
|
Yes
|
If table creation completed then enter some sample data such as follows..
PlaceID
|
PlaceName
|
PlaceLatitude
|
PlaceLongitude
|
PlaceDescription
|
1
|
Kolkata
|
22.5697
|
88.3697
|
This is Kolkata
|
2
|
Hyderabad
|
17.2667
|
78.5302
|
This is Hyderabad
|
3
|
Bangalore
|
12.8974
|
77.5195
|
This is Bangalore
|
4
|
Visakhapatnam
|
17.5183
|
83.3203
|
This is Visakhapatnam
|
5
|
Chennai
|
12.4974
|
83.3203
|
This is Chennai
|
Now write the following code in your aspx to show multiple markers in Google map from database like as shown below:
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Show/Add multiple markers to Google Maps from database in asp.net website</title>
<style type="text/css">
html { height: 100% }
body { height: 100%; margin: 0; padding: 0 }
#map_canvas { height: 100% }
</style>
<script type="text/javascript" src = "https://maps.googleapis.com/maps/api/js?key=AIzaSyC6v5-2uaq_wusHDktM9ILcqIrlPtnZgEk&sensor=false">
</script>
<script type="text/javascript">
function initialize() {
var markers = JSON.parse('<%=ConvertDataTabletoString() %>');
var mapOptions = {
center: new google.maps.LatLng(markers[0].lat, markers[0].lng),
zoom: 5,
mapTypeId: google.maps.MapTypeId.ROADMAP
// marker:true
};
var infoWindow = new google.maps.InfoWindow();
var map = new google.maps.Map(document.getElementById("map_canvas"), mapOptions);
for (i = 0; i < markers.length; i++) {
var data = markers[i]
var myLatlng = new google.maps.LatLng(data.lat, data.lng);
var marker = new google.maps.Marker({
position: myLatlng,
map: map,
title: data.title
});
(function(marker, data) {
// Attaching a click event to the current marker
google.maps.event.addListener(marker, "click", function(e) {
infoWindow.setContent(data.description);
infoWindow.open(map, marker);
});
})(marker, data);
}
}
</script>
</head>
<body onload="initialize()">
<form id="form1" runat="server">
<div id="map_canvas" style="width: 500px; height: 400px"></div>
</form>
</body>
</html>
Now add following namespaces in code behind
C# Code
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
After that write the following code in code behind
// This method is used to convert datatable to json string
public string ConvertDataTabletoString()
{
DataTable dt = new DataTable();
using (SqlConnection con = new SqlConnection("Data Source=localhost;Initial Catalog=positionmaster;Integrated Security=true"))
{
using (SqlCommand cmd = new SqlCommand("select title=PlaceName,lat=PlaceLatitude,lng=PlaceLongitude,PlaceDescription from LocationDetails", con))
{
con.Open();
SqlDataAdapter da = new SqlDataAdapter(cmd);
da.Fill(dt);
System.Web.Script.Serialization.JavaScriptSerializer serializer = new System.Web.Script.Serialization.JavaScriptSerializer();
List<Dictionary<string, object>> rows = new List<Dictionary<string, object>>();
Dictionary<string, object> row;
foreach (DataRow dr in dt.Rows)
{
row = new Dictionary<string, object>();
foreach (DataColumn col in dt.Columns)
{
row.Add(col.ColumnName, dr[col]);
}
rows.Add(row);
}
return serializer.Serialize(rows);
}
}
}
VB.NET Code
Imports System.Collections.Generic
Imports System.Data
Imports System.Data.SqlClient
Partial Class Default3
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
End Sub
' This method is used to convert datatable to json string
Public Function ConvertDataTabletoString() As String
Dim dt As New DataTable()
Using con As New SqlConnection("Data Source=localhost;Initial Catalog=positionmaster;Integrated Security=true")
Using cmd As New SqlCommand("select title=PlaceName,lat=PlaceLatitude,lng=PlaceLongitude,PlaceDescription from LocationDetails", con)
con.Open()
Dim da As New SqlDataAdapter(cmd)
da.Fill(dt)
Dim serializer As New System.Web.Script.Serialization.JavaScriptSerializer()
Dim rows As New List(Of Dictionary(Of String, Object))()
Dim row As Dictionary(Of String, Object)
For Each dr As DataRow In dt.Rows
row = New Dictionary(Of String, Object)()
For Each col As DataColumn In dt.Columns
row.Add(col.ColumnName, dr(col))
Next
rows.Add(row)
Next
Return serializer.Serialize(rows)
End Using
End Using
End Function
End Class
1 comments:
what is "JSON" in this code? thanks!
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