Introduction to VB.Net Internet Tools

Web Server Default directory –C:\InetPub\wwwroot –Computer lab: Zip drive dchao Default home page –Default.aspx, default.asp, default.htm

Web Project File/New/ ASP.Net Application Website folder Web form: –Webform.aspx Design view and HTML view –WebForm.Aspx.VB CodeBehind

Web Data Form Web Data Form Wizard: –Project/Add Web Form/Data Form Wizard

Bind the DataReader to a DataGrid Dim strConn As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source = c:\salesDB.mdb" Dim objConn As New OleDbConnection(strConn) Dim strSQL As String = "select * from customer;" Dim objComm As New OleDbCommand(strSQL, objConn) Dim Results As String objConn.Open() Dim objDataReader As OleDbDataReader objDataReader = objComm.ExecuteReader() DataGrid1.DataSource = objDataReader DataGrid1.DataBind() Note: DataGrid1.DataBind()

ASP.NET ASP.NET is a server-side technology for creating dynamic web pages. ASP.NET allows you to use a selection of full programming languages. The default language is VB.NET. ASP.NET files have a.aspx extension.

ASP.NET Object Model Client Server Request Object Response Object Server Object Session Object Application Object

ASP.NET Request Object When a page is requested, much information is passed along with the request, such as the URL, queryString, and data from a form. The request object allows you to get the information passed along with the request. It is created from the System.Web.HttpRequest class.

FORM Tag Form attribute: –Action: Specify the URL of a program on a server or an address to which a form’s data will be submitted. –Method: Get: the form’s data is appended to the URL specified by the Action attribute as a QueryString. Post: A prefered method for database processing. Form’s data is sent separately from the URL. –Name: Form’s name

QueryString A QueryString is a set of name=value pairs appended to a target URL. It can be used to pass information from one webpage to another. Example: ao

Request Object Collections QueryString – –cid = Request.queryString(“CustID”) –cName=Request.queryString(“CustName”) Form –A form with two text boxes:CustID, CustName –cid = Request.Form(“CustID”) –cName=Request.Form(“CustName”) Cookies

ASP.NET Response Object This object allows you to send information back to client. It is created from the System.Web.HttpResponse class. Properties: –Cookies (a collection) Methods: –Response.Write –Response.Redirect (“URL”) Demo: testReqForm.htm, testReqForm.aspx

Downloading Internet Resources Download the HTML of a web page and display it in a text box. –System.URI A class for expressing a Uniform Resource Identifier. –System.Net.WebRequest Makes a request to a Uniform Resource Identifier. –WebResponse Provides a response from a Uniform Resource Identifier. Demo: MyBrowser/GetWebPage

Imports System.IO Imports System.Net Imports System.Text Private Sub BtnGo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnGo.Click Dim URI As New Uri(txtURL.Text) Dim request As WebRequest = WebRequest.Create(URI) Dim response As WebResponse = request.GetResponse Dim stream As Stream = response.GetResponseStream Dim readStream As New StreamReader(stream) Dim webData As String = readStream.ReadToEnd stream.Close() readStream.Close() txtData.Text = webData End sub

Change Downloaded Page For example, use string’s Replace method to change page content. –webData = webData.Replace("Chao", "You") Search/Replace with Regular Expression

Using the WebClient Class This class wraps the Request and Response classes. Methods: –DownloadData: Returns a byte array from an Internet address. –DownloadFile: Save a downloaded file. –OpenRead: Returns a stream from an Internet address.

UTFEncoding Class This class encodes Unicode characters using UCS Transformation Format, 8-bit form (UTF-8). This encoding supports all Unicode character Method: GetString –Decodes the specified byte array into a string.

WebClient/Download Dim wc As New WebClient() Dim utf8 As New UTF8Encoding() Dim webData As String webData = utf8.GetString(wc.DownloadData(txtURL.Text)) txtData.Text = webData

WebClient/DownloadFile.Save the dowloaded data directly in a file: Dim wc As New WebClient() wc.DownloadFile(txtURL.Text, "c:\testDownLoad.txt")

WebClient/OpenRead Dim wc As New WebClient() Dim stream As Stream stream = wc.OpenRead(txtURL.Text) Dim readStream As New StreamReader(stream) Dim webData As String = readStream.ReadToEnd txtData.Text = webData

Hosting Internet Explorer in Windows Forms Internet Explorer COM control –Right click Tool Box Windows Form tab and select Add/Remove Items …. –Select COM Component tab, and Scroll down to select Microsoft Web Browser.

Internet Explorer COM control Events –DownLoadComplete, DownLoadBegin Methods: –Navigate Dim HomeURL As String = " Private Sub MyBrowser_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load IE.Navigate(HomeURL) End Sub –Note: Navigate can take local file path as input to open a local page. –Goback, GoForward –Stop –Refresh2 –GoHome, GoSearch --- (Go to Microsoft home page and search engine)

Web Service XML Web Service Web services are classes that are stored on the web which can instantiate and use in both Windows and Web applications.

A Web Service Example ASPET/TestWebService.ASMX imports System.Web.Services imports System imports System.Data imports System.Data.Oledb Public Class CustomerInfo public Function GetCname(ByVal CID as String) as String dim strConn as string ="Provider=Microsoft.Jet.OLEDB.4.0;Data Source = c:\sales2k.mdb" dim objConn as new OledbConnection(strConn) dim strSQL as string = "select * from customer where CID = '" & CID & "';" dim objComm as new OledbCommand(strSQL,objConn) dim Results as string objConn.open() dim objDataReader as oledbDataReader objDataReader=objComm.executeReader() objDataReader.read() return objDataReader("Cname") end function

Creating a Web Service Using VS New Project/ASP.Net Web Service

Web Service Description Language (WSDL) A WSDL file is an XML document containing a complete description of the web service. It shows a web service’s name, methods, and parameter types. Help page: After entering web service’s URL, a help page is displayed. You can click the Service Description link to see the WSDL file.

Consuming Web Services from a Windows Application Add a web reference to the web service. Declare a web service class variable. –Dim myWebService As New dchaolaptop.CustomerInfo() Demo: UseWebService

Universal Description, Discovery, and Integration (UDDI) A directory service for web services. –

Simple Mail Transport Protocol (SMTP) messages are text files. InetPub\MailRoot –PickUp directory: SMTP monitors this directory and sends any messages found in this directory. –Drop: Incoming messages received by SMTP are written to this directory. –BadMail: If an cannot be delivered or returned to the sender it is moved to this directory.

ASP.Net Classes SmtpMail class –System.Web.Mail –System.Web.Mail.MailMessage Methods: –Send(From, To, Subject, messageText) SmtpMail.Send(TextBox1.Text, TextBox2.Text, TextBox3.Text, TextBox4.Text) –Send(System.Web.Mail.MailMessage) Demo: –SendMail.aspx –Import system.web.mail

Using MailMessage Class to Set Properties properties: –Attachments –Bcc –Body –BodyFormat Text or Html –Cc –From –Headers –Subject –To

Using MailMessage with Attachment Dim objMsg As New MailMessage objMsg.From = TextBox1.Text objMsg.To = TextBox2.Text objMsg.Subject = TextBox3.Text objMsg.Body = TextBox4.Text Dim attachment As MailAttachment = New MailAttachment("c:\paradise.jpg") objMsg.Attachments.Add(attachment) Try SmtpMail.Send(objMsg) Catch ex As SystemException MessageBox.Show(ex.Message) End Try