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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

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Web server l.jpg
Web Server

  • Default directory

    • C:\InetPub\wwwroot

    • Computer lab: Zip drive

      • dchao

  • Default home page

    • Default.aspx, default.asp, default.htm


Web project l.jpg
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 l.jpg
Web Data Form

  • Web Data Form Wizard:

    • Project/Add Web Form/Data Form Wizard


Bind the datareader to a datagrid l.jpg
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 l.jpg
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 l.jpg
ASP.NET Object Model

Client

Server

Request Object

Server

Object

Response Object

Application

Object

Session

Object


Asp net request object l.jpg
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 l.jpg
FORM Tag

  • Form attribute:

    • Action: Specify the URL of a program on a server or an email 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 l.jpg
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:

  • <A Href=“http://my.com/Target.htm?CustID=C1&Cname=Chao”>


Request object collections l.jpg
Request Object Collections

  • QueryString

    • http://my.com/Target.htm?CustID=C1&CustName=Chao

    • 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 l.jpg
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 l.jpg
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


Slide14 l.jpg

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 l.jpg
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 l.jpg
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 l.jpg
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 l.jpg
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 l.jpg
WebClient/DownloadFile

.Save the dowloaded data directly in a file:

Dim wc As New WebClient()

wc.DownloadFile(txtURL.Text, "c:\testDownLoad.txt")


Webclient openread l.jpg
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 l.jpg
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 l.jpg
Internet Explorer COM control

  • Events

    • DownLoadComplete, DownLoadBegin

  • Methods:

    • Navigate

      • Dim HomeURL As String = "http://dchaolaptop"

      • 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 l.jpg
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 l.jpg
A Web Service ExampleASPET/TestWebService.ASMX

<%@ WebService Class="CustomerInfo" %>

imports System.Web.Services

imports System

imports System.Data

imports System.Data.Oledb

Public Class CustomerInfo

<webMethod()> 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 l.jpg
Creating a Web Service Using VS

  • New Project/ASP.Net Web Service


Web service description language wsdl l.jpg
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 l.jpg
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 l.jpg
Universal Description, Discovery, and Integration (UDDI)

  • A directory service for web services.

    • http://uddi.org


Simple mail transport protocol smtp l.jpg
Simple Mail Transport Protocol (SMTP)

  • Email 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 email cannot be delivered or returned to the sender it is moved to this directory.


Asp net email classes l.jpg
ASP.Net Email 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 email properties l.jpg
Using MailMessage Class to Set Email Properties

  • Email properties:

    • Attachments

    • Bcc

    • Body

    • BodyFormat

      • Text or Html

    • Cc

    • From

    • Headers

    • Subject

    • To


Using mailmessage with attachment l.jpg
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


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