Visual Basic.NET ProgrammingMarch 3, 2004

Agenda

• Questions / Discussion

• Cookies

• Project Work (Ends Around 9:00 PM)

• Demo's (15 minutes per team)

Questions

• All homework homework due by Friday.

• Web Site will remain available for awhile, if not, contact me, I'll have the material.

• a tip... use the Microsoft Web Site Advanced Search to look up errors. I think it works half of the time.

Cookies

Cookies• Cookies are a way to save information on the

client machine between web page requests.

• A cookie is a name/value pair that the browser saves on behalf of the application.

• Cookies are keyed to the domain of the application.

• When a browser requests a page it automatically transmits the cookies that belong to that domain as part of the request.

• The application then reads the cookies and takes appropriate action.

Cookies

Cookies are generally used in two ways.

1. To save some sort of user identifying information about the user, so that when the returns to a given site, the application knows who the user is.

2. The other is to save information indicating the application's state between web page requests within a single session.

Although any information can be saved in a cookie, best practice is to use some sort of key to look up the actual information of the server.

Cookies

Cookies are created by adding items to the Cookies collection of the ASP.NET Response object (available through the Response property of the Page Class).

ExampleDim cookie as HttpCookie

cookie = New HttpCookie("MyCookie","MyCookieValue")

Response.Cookies.Add(cookie)

Cookies

Cookies are read from the Cookies collection of the ASP.NET Request object (available through the Request property of the Page Class).

ExampleDim cookie as HttpCookie

cookie = Request.Cookies("MyCookie")

Label1.Text = cookie.Value

HttpCookie Properties• Domain – the domain associated with the cookie (string).• Expires – date and time the cookie expires (datetime).• HasKeys – whether the cookie as subkeys (boolean).• Item – old ASP way of accessing subkeys, indexed by

subkey name.• Name – the name of the cookie (string).• Path – the path associated with the cookie (string).• Secure – does the cookies require a secure transmission

(boolean).• Value – the value of the cookie (string).• Values – if the cookie as subkeys, Values represents an

instance of a NameValuesCollection.

Topics Covered in the

Visual Basic.NET ProgrammingCourse

Console Application

Command Window

Console Application

Windows Form Class

Input Screen

Windows Form Application

Constructors

Fields

Get Set Properties

Methods

Windows Form Class

Class

Input Screen

Windows Form with Class DLL

Database

Constructors

Fields

Get Set Properties

MethodsWindows Form

Class

ClassInput Screen

Windows Form, Class DLL, and ADO

WebForm Class

Browser (IE6)

WebForm Application

Code Behind File

Database

Constructors

Fields

Get Set Properties

Methods

WebForm Class

ClassBrowser (IE6)

WebForm, Class DLL, and ADO

Code Behind File

Database

Constructors

Fields

Get Set Properties

Methods

WebForm Class

ClassBrowser (IE6)

Web Services using localhost

Code Behind File

SOAP

Database

Constructors

Fields

Get Set Properties

Methods

WebForm Class

ClassBrowser (IE6)

Web Services using Remote Host

Code Behind File

Client Server

SOAP

Web Form Client Private Sub Button1_Click(ByVal sender As System.Object,

ByVal e As System.EventArgs) Handles Button1.Click

Label1.text = ""

Try

Dim obj As New Service1

Dim ds As New DataSet

Dim str As String = "Select * from NameAddress"

ds = obj.ServiceGetDataSet(str)

DataGrid1.DataSource = ds

DataGrid1.DataBind()

Catch ex As Exception

Label1.text = ex.Message

End Try

End Sub

Web Service <WebMethod()> _

Public Function ServiceGetDataSet(ByVal SQLStmt As String) As DataSet

Try

Dim obj As New CDatabase

Dim ds As New DataSet

obj.SQLString = SQLStmt

If obj.GetDataSet(ds) Then

Return ds

End If

Catch ex As Exception

Dim se As New SoapException("Fault occurred - " + ex.Message,

SoapException.ClientFaultCode)

Throw se

End Try

End Function

Database Class Notes

• Don't name everything DatabaseClass

• Name the Project DatabaseClass

• Name the .vb module DBClass

• Name the class Cdatabase

• Check the project properties to determine the imports name to use in the application

Database Class Private cn As New OleDbConnection()

Private adpt As New OleDbDataAdapter()

Private m_SQLString As String

Public Sub New()

End Sub

Public Property SQLString()

Get

Return m_SQLString

End Get

Set(ByVal Value)

m_SQLString = Value

End Set

End Property

Database Class Public Function GetDataSet(ByVal ds As DataSet) As Boolean

Try

If Not OpenConnection() Then

Throw New ApplicationException("Connection Open Failure")

End If

adpt = New OleDbDataAdapter(m_SQLString, cn)

adpt.Fill(ds, "Messages")

adpt.Dispose()

Catch ex As Exception

Throw New ApplicationException("Database Error - " + ex.Message)

Finally

cn.Close()

cn = Nothing

End Try

Return True

End Function

Database Class

Private Function OpenConnection() As Boolean

Try

If cn.State <> ConnectionState.Open Then

cn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" & _

"Data Source=C:\...\Guestbook.mdb"

cn.Open()

Return True

End If

Catch ex As Exception

Throw New ApplicationException("Connection Failure - " + ex.Message)

End Try

End Function