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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
Web Server
  • Default directory
    • C:\InetPub\wwwroot
    • Computer lab: Zip drive
      • dchao
  • Default home page
    • Default.aspx, default.asp, default.htm
web project
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
  • Web Data Form Wizard:
    • Project/Add Web Form/Data Form Wizard
bind the datareader to a datagrid
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
  • 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
ASP.NET Object Model

Client

Server

Request Object

Server

Object

Response Object

Application

Object

Session

Object

asp net request 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 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
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
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
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
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

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
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
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
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
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
WebClient/DownloadFile

.Save the dowloaded data directly in a file:

Dim wc As New WebClient()

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

webclient openread
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
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
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
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
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
Creating a Web Service Using VS
  • New Project/ASP.Net Web Service
web service description language wsdl
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
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
Universal Description, Discovery, and Integration (UDDI)
  • A directory service for web services.
    • http://uddi.org
simple mail transport protocol smtp
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
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
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
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