What is ajax? ajax code, ajax examples: Using AJAX in ASP.NET technology through Atlas.

AJAX (Asynchronous JavaScript and XML) is a cross platform technology publish. This technology allows developers to perform asynchronous requests to the Web, using the markup language of XML.
Technology firms Microsoft code-named "Atlas" enables the use AJAX to create server applications based on ASP.NET 2.0 technology.
This article focuses on a simple Web-based applications to dynamically on the client side complete data pull-down list and make dynamic loading additional information from the database using ASP.NET 2.0, AJAX and Atlas.
To begin with the Atlas technology to download an extension to Visual Studio 2005. You can do this with the Microsoft site (download).
With this expansion should create a new Web project using the template "ASP.NET 'Atlas' Web Site" (Fig. 1)

Fig. one window for a new project based on the template

Fig. 2 Sozdavaemaya table sprEmployee

After setting up a database and fill it Which of you are ready to create web necessary to extract information from the database in XML format.
To create a web in the window, select "Solution" Exploler up project, and then to me Website select Add New Item. In the dialog box (Figure 3) choose a template Web Service, a name WebAccess.asmx and remove tick Place code in separate file.

Fig. 3 window of a new web

Now add code to our web :

<% @ WebService Language = "VB" Class = "WebAccess"%> Imports System.Web Imports System.Web.Services Imports System.Web.Services.Protocols Imports System.Collections Imports System.Data.SqlClient <WebService(Namespace:="http://tempuri.org/")> _ <WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _ Public Class WebAccess Inherits System.Web.Services.WebService Public Structure EmployeeLittleRec 'structure to send data on accounts Dim Name As String' Name your ID As Integer Dim 'account Cod End Structure Private Structure EmployeeRec' structure to provide more information about account Dim Name As String 'Account Name Dim Password As String 'Password account Dim DateBegin As Date' Established Dim DateEnd As Date 'Data disposal Dim Comments As String' Comments End Structure'' ' <summary> " 'The receipt of additional information on the account code''' </summary> '' 'code account </param> '' ' <returns> Get HTML code containing the account information </returns> <WebMethod()> _ Public Function GetFullEmployeeInfo (ByVal IDEmployee As Integer) As String Dim Rec As EmployeeRec Dim ReturnStr As String Dim con As New SqlConnection ( "workstation id = Test; packet size = 4096; Data Source = crash; Initial Catalog = WebAccess; user id = sa ") 'For a connection to the database con.Open ()' Open Connection (here certainly need to intercept exceptions, but this article is not about this) Dim command As New SqlCommand ( "SELECT * FROM WHERE sprEmployee IDEmployee =" & CStr (IDEmployee) con) 'Create a request to our table Dim dbReader As SqlDataReader dbReader = command.ExecuteReader ()' Create a SqlDataReader reading of the table If dbReader.Read Then Rec.Name = CStr (dbReader ( "Name")) Rec.Password = CStr (dbReader ( "Password")) Rec.DateBegin = CDate (dbReader (DateBegin ")) If Not IsDBNull (dbReader (" DateEnd ")) Then Rec.DateEnd = CDate (dbReader (" DateEnd ")) Else Rec.DateEnd = Nothing End If Rec.Comments = CStr (dbReader (" Comments ")) = ReturnStr String.Format ( " Name : (0) Password : (1) Date Connection : (2) Date off : (3) Comments : (4) "Rec.Name, Rec.Password, Rec.DateBegin, Rec.DateEnd, Rec.Comments) 'Creating HTML which will be launched immediately to Else ReturnStr =" Error getting' list was not found End If con.Close con.Dispose () () Return ReturnStr End Function'' ' <summary> " 'The need for a list of accounts''' </summary> " 'The maximum number of entries </param> '' ' <returns> An array of information on records </returns> <WebMethod()> Public Function GetEmployee (ByVal Count As Integer) As Generic.List (Of EmployeeLittleRec) Dim sql As String Dim ListRec As New Generic.List (Of EmployeeLittleRec) 'Creating an array Dim OneRec As EmployeeLittleRec Dim ReturnStr As String = "" Dim con As New SqlConnection ( "workstation id = Test; Packet size = 4096; Data Source = crash; Initial Catalog = WebAccess; User id = sa ") con.Open () 'Connect to the database Dim command As SqlCommand If Count> 0 Then 'Checking whether a number of displayed records sql = String.Format ( "SELECT TOP (0) IDEmployee, Name FROM sprEmployee" Count) Else sql = "SELECT IDEmployee, Name FROM sprEmployee" End If command = New SqlCommand (sql, con) Dim dbReader As SqlDataReader dbReader = command.ExecuteReader Do Not Until dbReader.Read 'Fill array accounts OneRec.ID = dbReader (IDEmployee) OneRec.Name = dbReader ( "Name") ListRec.Add (OneRec) Loop con.Close con.Dispose () () Return ListRec' Check array End Function End Class

Code Listing 1 Source Code Web

Now proceed to a web page to access information on the accounts. To that end, providing the box "Solution" Exploler up in the draft and selecting a menu item Website Add New Item, ask relevant parameters created a page (Figure 4). :
Template-Web Form.
Name-AtlasDropDown.aspx.
Similarly Place code in separate file-removed.

Fig. 4 Create a new web page
After creating a web introduce a code necessary for the work.

<% @ Page Language = "VB"%> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <script runat="server"> </script> Testing Atlas <script language="javascript" type="text/javascript"> // <!CDATA[ /////////////////////////////////////////////////////////////////// //JavaScript для работы с веб-службой и обработка клиентских событий /////////////////////////////////////////////////////////////////// function bttnLoadToDropDown_onclick() //Функция обработки клика по кнопке "Загрузить список" { document.getElementById('SplashScreen').style.display='block'; //Показываем "идет загрузка" var Count =document.getElementById('txtCount').value; //Получение кол-ва выводимых записей WebAccess.GetEmployee(Count,OnCallBackResult); //Выполнение запроса к веб-службе, где OnCallBackResult -функция обратного вызова } function OnCallBackResult(result) //Описание функции обратного вызова, в которую возвращается результат { var ddl =document.getElementById('ddlEmployee'); //Объявляем наш выпадающий список var i; for (i=0;i<result.length;i++) { ddl.options[i]=new Option(result[i].Name,result[i].ID); //Добавляем в список загруженные данные } document.getElementById('SplashScreen').style.display='none'; //Скрываем "идет загрузка" } function ddlEmployee_onchange() { document.getElementById('SplashScreen').style.display='block'; //Показываем "идет загрузка" WebAccess.GetFullEmployeeInfo(document.getElementById('ddlEmployee').value,On CallBackFullInfo); //Выполнение запроса к веб-службе } function OnCallBackFullInfo(result) { document.getElementById('FullInfo').innerHTML=result //Показываемый полученных HTML пользователю document.getElementById('SplashScreen').style.display='none'; //Скрываем "идет загрузка" } // ]]> </script> <form id="form1" runat="server"> <% -- Obyavlyaem of Atlas --%> <atlas:ScriptManager ID="ScriptManager1" runat="server"> <Services> <% -- Obyavlyaem link to our Web services --%> <atlas:ServiceReference Path="WebAccess.asmx" Type="text/javascript" /> </Services> </atlas:ScriptManager> <% -- For an object to display the boot --%> <div id="SplashScreen" style="position: absolute; display: none; left: 246px; width: 476px; top: 141px; height: 49px; text-align: justify;"> <h2> Is Data </h2> </div> <div> <input id="txtCount" style="width: 147px" type="text" value="0" /> <input id="bttnLoadToDropDown" type="button" value="Загрузить список" onclick="return bttnLoadToDropDown_onclick()" /> </div>

Code Listing 2 source code web

Now start up project implementation. If all goes well, you should show that the browser window (Figure 5), and after downloading the list and select a record you will about this type as in Fig.

What is ajax? ajax code, ajax examples

Monday, June 11, 2007

Using AJAX in ASP.NET technology through Atlas.

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