Ajax DLL
Introduction
Ajax DLL is a library developed using .NET 2005 for ASP.NET 2.0/3.0/3.5/4.0. It is used to call Server side methods from JavaScript. You can pass the method parameter value from JavaScript. A parameter can be a variable or an object.
In the given example, I have used the parameter as a string variable, an array object and a class object. A benefit of this DLL is that you can use it at UserControl level, so if you have some method in UserControl and you want to call it via JavaScript, you can achieve it using this DLL. A drawback of this DLL is that you cannot access your server control in your method, because Page Life Cycle is not involved during the method call. But you can access your server control from JavaScript and assign the value which will be returned by Ajax method.
Using the Code
It’s very simple to use Ajax DLL. You need to create a web application or a web site and add reference of Ajax.dll which is in the attached file.
Once a DLL has been added into your application, you need to place a one line code on Page_Load event as below:
This code will register your page class in DLL with all your AJAX method[s] written in the page class, which are given in the image below. Check the below image, you will find that the methods have been annotated with an attribute Ajax.AjaxMethod. You need to annotate with an attribute to the methods which you want to call from JavaScript.
There are 5 optional parameters with the Ajax.AjaxMethod attribute:
- Method name: A method which you want to call from JS. Default will be the same method name which you have created.
- Js Callback method name: On Successful End Request of the Ajax call. Default will be the Callback_<your method name>.
- Js Error method Name: Any Error at the time of End Request of the Ajax call. Default will be the Error_<your method name>.
- Loading Text: Which text you want to show. Default Text is
string.Empty. - Asynchronous Call: Boolean value, used to make your call synchronous from JavaScript. Default Value is
True.
Once the methods have been written, you can call all these methods from JS as defined in the first parameter of Ajax.AjaxMethod. For that, you can write JS methods as below: 
Check here the CallTest1() function, from the function PassArrayObject method is called as defined in the first parameter of Ajax attribute. The parameter value and the method name should be the same. Also check the last function CallReturnEvenOdd(), for which callback method or error method is not required, because its server method ReturnEvenOdd is defined with "IsAsync=false" parameter (check the previous image). So value will be returned to the same function CallReturnEvenOdd().
At last, you need to apply some configuration in the web.config file as below:
Find the HTML code here:
<%@ Page Language="C#" AutoEventWireup="true"
Codebehind="Default.aspx.cs" Inherits="DemoAjaxApp._Default" %>
<%@ Register Assembly="System.Web.Extensions, Version=1.0.61025.0,
Culture=neutral, PublicKeyToken=31bf3856ad364e35"
Namespace="System.Web.UI" TagPrefix="asp" %>
<!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 runat="server">
<title>Ajax Demo</title>
<script language="javascript" type="text/javascript">
function CallTest()
{
var id=document.getElementById('txtClientId').value;
Test(id);
}
function NameLength(obj)
{
var i=0;
var newdiv = document.getElementById('EmpData');
newdiv.innerHTML = "";
if(obj == null)
{
newdiv.innerHTML = "No Employee Found";
return;
}
mytable = document.createElement("table");
mytable.cellSpacing = "0px";
mytable.style.border = "1px solid #000";
mytablebody = document.createElement("tbody");
mycurrent_row = document.createElement("tr");
for(i=0;i<obj.Rows[0].Columns.length;i++)
{
mycurrent_cell = document.createElement("td");
currenttext = document.createTextNode
(obj.Rows[0].Columns[i].Name);
mycurrent_cell.appendChild(currenttext);
mycurrent_cell.style.border =
"1px solid #000";
mycurrent_row.appendChild(mycurrent_cell);
}
mytablebody.appendChild(mycurrent_row);
for(var j=0;j<obj.RowCount;j++)
{
var objRow = obj.Rows[j];
mycurrent_row = document.createElement("tr");
for(i=0;i<objRow.Columns.length;i++)
{
mycurrent_cell =
document.createElement("td");
if(objRow.Columns[i].Value != null)
currenttext =
document.createTextNode
(objRow.Columns[i].Value
+ " ");
else
currenttext =
document.createTextNode(" ");
mycurrent_cell.appendChild
(currenttext);
mycurrent_cell.style.border =
"1px solid #000";
mycurrent_row.appendChild
(mycurrent_cell);
}
mytablebody.appendChild(mycurrent_row);
}
mytable.appendChild(mytablebody);
newdiv.appendChild(mytable);
}
function Error_Test(obj)
{
alert(obj.ErrMsg);
}
function CallTest1()
{
var x = new Array();
x[0] = "Mehul";
x[1] = "Thakkar";
PassArrayObject(x);
}
function ReturnClassObject(obj)
{
alert(obj.Name);
}
function Error_PassArrayObject(obj)
{
alert(obj.ErrMsg);
}
function CallReturnEvenOdd()
{
var id = document.getElementById('txtNumber').value;
var msg = ReturnEvenOdd(id);
alert(msg);
}
function CallTest2()
{
var x = new Object();
x.Name = "Mehul-Thakkar";
x.Phone = 25460645;
x.Email = "mehult@xyz.com";
x.JoiningDate = "15-09-2010";
PassClassObject(x);
}
function ReturnLength(obj)
{
alert(obj);
}
function Error_PassClassObject(obj)
{
alert(obj.ErrMsg);
}
function CallBack_ReturnArray(arrObj)
{
var Total=0;
for(var i in arrObj)
Total+=parseInt(arrObj[i],10);
alert(Total);
}
function CallBack_ReturnStrArray(arrObj)
{
var str='';
for(var i in arrObj)
str+=arrObj[i]+"\n";
alert(str);
}
function CallBack_ReturnObject(clsObj)
{
alert(clsObj.Email);
}
function CallBack_ReturnFArray(arrObj)
{
var Total=0;
for(var i in arrObj)
Total+=parseFloat(arrObj[i],10);
alert(Total);
}
</script>
</head>
<body>
<form id="form1" runat="server">
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<div>
<div style="border: solid 1px yellow">
Enter Emp No Here:
<input type="text" id="txtClientId" />
<a href="#" onclick="CallTest()">Retrieve Emp</a>
<div id="EmpData">
</div>
</div>
<br />
<div style="border: solid 1px blue">
Pass Array Object:
<a href="#" onclick="CallTest1()">Click Here</a>
<div id="Div1">
</div>
</div>
<br />
<div style="border: solid 1px green">
Pass Class Object:
<a href="#" onclick="CallTest2()">Click Here</a>
<div id="Div2">
</div>
</div>
<br />
<div style="border: solid 1px orange">
Return Array Object:
<a href="#" onclick="ReturnArray()">Click Here</a>
<div id="Div3">
</div>
</div>
<br />
<div style="border: solid 1px brown">
Return String Array Object:
<a href="#" onclick="ReturnStrArray()">Click Here</a>
<div id="Div5">
</div>
</div>
<br />
<div style="border: solid 1px pink">
Return Double Array Object:
<a href="#" onclick="ReturnFArray()">Click Here</a>
<div id="Div6">
</div>
</div>
<br />
<div style="border: solid 1px gray">
Return Class Object:
<a href="#" onclick="ReturnObject()">Click Here</a>
<div id="Div4">
</div>
</div>
<br />
<div style="border: solid 1px silver">
Synchronous Call using AJAX:
<input type="text" id="txtNumber" />
<a href="#" onclick="CallReturnEvenOdd()">Click Here</a>
<div id="Div7">
</div>
</div>
<br />
<div style="border: solid 1px red">
Access this textbox from Ajax dll
<asp:TextBox runat="server" ID="txt"></asp:TextBox>
<a href="#" onclick="ControlAccess()">Get Error</a>
</div>
</div>
<asp:UpdatePanel runat="server" ID="UP1">
<ContentTemplate>
<asp:TextBox runat="server" ID="txt1">
</asp:TextBox>
<asp:Button runat="server" ID="b1" Text="click here" OnClick="b1_Click" />
</ContentTemplate>
</asp:UpdatePanel>
</form>
</body>
</html>
Find the CS file code here:
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
namespace DemoAjaxApp
{
public class Temp
{
string _name, _email;
int _phone;
public string Name { get { return _name; } set { _name = value; } }
public int Phone { get { return _phone; } set { _phone = value; } }
public string Email { get { return _email; } set { _email = value; } }
}
public partial class _Default : System.Web.UI.Page
{
[Ajax.AjaxMethod("Test", "NameLength", null, "Loading...")]
public DataTable Test(string Id)
{
System.Data.SqlClient.SqlConnection con =
new System.Data.SqlClient.SqlConnection
("server=mehul;Database=master;User Id=sa;Password=");
System.Data.SqlClient.SqlDataAdapter Adp =
new System.Data.SqlClient.SqlDataAdapter
("Select * from emp where no=" + Id, con);
DataTable dt = new DataTable();
try
{
Adp.Fill(dt);
if (dt.Rows.Count > 0)
return dt;
else
return null;
}
catch (Exception ex)
{
return null;
}
}
[Ajax.AjaxMethod("PassArrayObject", "ReturnClassObject", null, "Loading...")]
public Temp PassArrayObject(string[] str)
{
Temp t1 = new Temp();
foreach (string st in str)
t1.Name += st;
return t1;
}
[Ajax.AjaxMethod("PassClassObject", "ReturnLength", null, "Loading...")]
public int PassClassObject(Temp str)
{
return str.Name.Length;
}
[Ajax.AjaxMethod("ControlAccess", false, false, "Loading...")]
public void ControlAccess(string str)
{
txt.Text = str;
}
[Ajax.AjaxMethod(false)]
public string ReturnEvenOdd(int i)
{
if (i % 2 == 0)
return "Number is Even";
else
return "Number is Odd";
}
[Ajax.AjaxMethod(null, true, false, "Loading...")]
public int[] ReturnArray()
{
int[] i ={ 1, 2, 3, 4 };
return i;
}
[Ajax.AjaxMethod]
public string[] ReturnStrArray()
{
string[] str ={ "\\'1\\'", "2", "3", "4" };
return str;
}
[Ajax.AjaxMethod(null, true, false, "Loading...")]
public double[] ReturnFArray()
{
double[] i ={ 1.423, 2.543, 3.765, 4.65 };
return i;
}
[Ajax.AjaxMethod(null, true, false, null)]
public Temp ReturnObject()
{
Temp obj = new Temp();
obj.Name = "hello";
obj.Phone = 420840;
obj.Email = "hello@helo.com";
return obj;
}
protected void Page_Load(object sender, EventArgs e)
{
Ajax.Utility.GenerateMethodScripts(this);
}
protected void b1_Click(object sender, EventArgs e)
{
txt1.Text = "hello";
}
}
}
History
- 9th Jul, 2011: Article updated
- No need to add extensions "ajax" & "ajaxj" in IIS.
- "
ShowLoading" parameter is removed. If you don't want to display loading message, passstring.emptyornull. - New Parameter "
IsAsync" is introduced, default value istrue. Iffalse, then it will make synchronize call from JavaScript. No Callback or Error method is required to handle it. - Less JS rendering. Performance is improved.
- 9th February, 2010: Article updated
- 17th November, 2009: Initial post