Programming Microsoft Visual Basic .NET/Programming Microsoft Visual Basic .NET (Microsoft Press)(X08-78517)(2002).bin/24 aspnet applications/aspnetapplications/responseform.aspx.vb

Text File | 2002-03-18 | 10.9 KB | 310 lines

Public Class ResponseForm
    Inherits System.Web.UI.Page

    Protected WithEvents HyperLink1 As System.Web.UI.WebControls.HyperLink
    Protected WithEvents btnImage As System.Web.UI.WebControls.LinkButton
    Protected WithEvents txtImageTitle As System.Web.UI.WebControls.TextBox
    Protected WithEvents btnCookie As System.Web.UI.WebControls.LinkButton
    Protected WithEvents txtCookieName As System.Web.UI.WebControls.TextBox
    Protected WithEvents txtCookieValue As System.Web.UI.WebControls.TextBox
    Protected WithEvents litCookieValues As System.Web.UI.WebControls.Literal
    Protected WithEvents litSessionInfo As System.Web.UI.WebControls.Literal
    Protected WithEvents litApplicationInfo As System.Web.UI.WebControls.Literal
    Protected WithEvents chkConvert As System.Web.UI.WebControls.CheckBox
    Protected WithEvents Image1 As System.Web.UI.WebControls.Image

#Region " Web Form Designer Generated Code "

    'This call is required by the Web Form Designer.
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()

    End Sub

    Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init
        'CODEGEN: This method call is required by the Web Form Designer
        'Do not modify it using the code editor.
        InitializeComponent()
    End Sub

#End Region

    ' Depending on the value you pass to the query string,
    ' this page works  to retrieve a file ,an image
    ' inside the page itself, and a file.

    Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        If Request.QueryString("docTitle") <> "" Then
            ' if the docTitle argument is used, display the requested file
            ShowDoc(Request.QueryString("docTitle"))

        ElseIf Request.QueryString("imgtitle") <> "" Then
            ' if the imgTitle argument is specified, dynamically create
            ' an image with rotated versions of the given sentence
            ShowImage(Request.QueryString("imgtitle"))
        Else
            ' otherwise the page is executing regularly

            ' Activate the output filter if requested
            If chkConvert.Checked Then
                Response.Filter = New ConvertTagFilter(Response.Filter)
            End If

            ' show how you can read a shared variable defined in Global.asax
            Session("Counter") = Globals.Counter

            ' Show information about the Response object
            ShowCookies()
            ShowSessionInfo()
            ShowApplicationInfo()
        End If
    End Sub

    ' send the browser a document at the specified path

    Sub ShowDoc(ByVal path As String)
        ' convert to a physical path.
        path = Request.MapPath(path & ".html")

        If System.IO.File.Exists(path) Then
            Response.Write("Here's the document you've requested<p>")
            Response.WriteFile(path)
        Else
            Response.Write("Sorry, no document with this name.")
        End If
        ' prevent the remainder of the page from executing as usual
        Response.End()
    End Sub

    ' send the browser an image that is created dynamically
    ' by rotating the text that is passed as an argument

    Sub ShowImage(ByVal imgTitle As String)
        ' Create a bitmap with given width, height, and color depth.
        Dim bmp As New Bitmap(400, 200, Drawing.Imaging.PixelFormat.Format16bppRgb565)
        ' Get the underlying Graphics object.
        Dim gr As Graphics = Graphics.FromImage(bmp)
        ' Clear its background.
        gr.Clear(Color.Red)

        ' create a font
        Dim fnt As New Font("Arial", 16, FontStyle.Regular, GraphicsUnit.Point)

        ' rotate it
        Dim angle As Single
        For angle = 0 To 360 Step 30
            ' Reset coordinate transforms.
            gr.ResetTransform()
            ' Translate and rotate the coordinate system.
            gr.TranslateTransform(200, 100)
            gr.RotateTransform(angle)
            ' Draw the (rotated) string.
            gr.DrawString(imgTitle, fnt, Brushes.Black, 0, 0)
        Next

        ' Clear current content and set returned content type.
        Response.Clear()
        Response.ContentType = "image/jpeg"
        ' Save to the Response.OutputStream object
        bmp.Save(Response.OutputStream, Imaging.ImageFormat.Jpeg)

        ' Release resources.
        fnt.Dispose()
        gr.Dispose()
        bmp.Dispose()

        ' prevent the remainder of the page from executing as usual
        Response.End()
    End Sub

    ' refresh the form with a new dynamically-generated image

    Private Sub btnImage_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnImage.Click
        ' change the ImageUrl of the Image control, so that it makes
        ' a request to this same page.
        Image1.ImageUrl = Request.Url.AbsolutePath & "?imgtitle=" & txtImageTitle.Text
    End Sub

    ' create a new cookie with given name and value

    Private Sub btnCookie_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCookie.Click
        ' Create a cookie with given name and value
        Dim cookie As New HttpCookie(txtCookieName.Text, txtCookieValue.Text)
        ' set its expiration date (2 weeks from now)
        cookie.Expires = Now.AddDays(14)
        ' send it to the client
        Response.Cookies.Add(cookie)
        ' redisplay the list of cookies
        ShowCookies()
    End Sub

    ' show all cookies

    Sub ShowCookies()
        ' Display all the cookies in a Repeated control
        Dim msg As String
        Dim cookieName As String
        For Each cookieName In Request.Cookies.AllKeys
            ' Get the cookie with given name.
            Dim cookie As HttpCookie = Request.Cookies(cookieName)
            ' DIsplay info on this cookie.
            msg &= String.Format("<b>{0}</b> = {1}<br>", cookieName, cookie.Value.ToString)
        Next
        litCookieValues.Text = msg
    End Sub

    ' show all Session properties and variables

    Sub ShowSessionInfo()
        Dim msg As String

        ' display important Session properties
        msg &= "<b>SessionID</b> = " & Session.SessionID & "<br>"
        msg &= "<b>LCID</b> = " & Session.LCID & "<br>"
        msg &= "<b>CodePage</b> = " & Session.CodePage & "<br>"
        msg &= "<b>IsCookieless</b> = " & Session.IsCookieless & "<br>"
        msg &= "<b>IsNewSession</b> = " & Session.IsNewSession & "<br>"
        msg &= "<b>IsReadOnly</b> = " & Session.IsReadOnly & "<br>"
        msg &= "<b>Mode</b> = " & Session.Mode.ToString & "<br>"
        msg &= "<b>Timeout</b> = " & Session.Timeout & "<p>"

        ' change the value of a Session variable, but only if
        ' Sessions aren't in ReadOnly mode
        If Not Session.IsReadOnly Then
            Session.Add("color", "red")
            If Session("price") Is Nothing Then
                Session.Add("price", 20)
            Else
                Session("price") = CInt(Session("price")) + 10
            End If
        End If

        Dim key As String
        For Each key In Session.Keys
            msg &= String.Format("<b>{0}</b> = {1}<br>", key, Session.Item(key))
        Next
        msg &= "<p><b>Response.ApplyAppPathModifier(""anotherpage.aspx"")</b> = <br>" & _
            Response.ApplyAppPathModifier("anotherpage.aspx") & "<p>"

        ' display the result
        litSessionInfo.Text = msg
    End Sub

    ' show Application variables

    Sub ShowApplicationInfo()
        Dim msg As String

        'use the new Add method to create two variables.
        Application.Add("quantity", "red")
        Application.Add("total ", 2345)

        ' display all Application variables.
        Dim key As String
        For Each key In Application.Keys
            msg &= String.Format("<b>{0}</b> = {1}<br>", key, Application(key))
        Next
        litApplicationInfo.Text = msg
    End Sub

End Class

' this class works as a Response filter
' it converts all <B> tags into <STRONG>

Class ConvertTagFilter
    Inherits System.IO.Stream

    ' save Stream variables
    Private m_stream As System.IO.Stream
    Private m_position As Long

    ' the constructor is passed the original output stream

    Public Sub New(ByVal sink As System.IO.Stream)
        m_stream = sink
    End Sub

    ' The following members of Stream must be overriden.

    Public Overrides ReadOnly Property CanRead() As Boolean
        Get
            Return True
        End Get
    End Property

    Public Overrides ReadOnly Property CanSeek() As Boolean
        Get
            Return True
        End Get
    End Property

    Public Overrides ReadOnly Property CanWrite() As Boolean
        Get
            Return True
        End Get
    End Property

    Public Overrides ReadOnly Property Length() As Long
        Get
            Return 0
        End Get
    End Property

    Public Overrides Property Position() As Long
        Get
            Return m_position
        End Get
        Set(ByVal Value As Long)
            m_position = Value
        End Set
    End Property

    Public Overrides Function Seek(ByVal offset As Long, ByVal direction As System.IO.SeekOrigin) As Long
        Return m_stream.Seek(offset, direction)
    End Function

    Public Overrides Sub SetLength(ByVal length As Long)
        m_stream.SetLength(length)
    End Sub

    Public Overrides Sub Close()
        m_stream.Close()
    End Sub

    Public Overrides Sub Flush()
        m_stream.Flush()
    End Sub

    Public Overrides Function Read(ByVal bytes() As Byte, ByVal offset As Integer, ByVal count As Integer) As Integer
        m_stream.Read(bytes, offset, count)
    End Function

    ' Write is the method that actually does the filtering.

    Public Overrides Sub Write(ByVal bytes() As Byte, ByVal offset As Integer, ByVal count As Integer)
        ' Copy the byte array into an array of chars.
        Dim chars(count - 1) As Char
        Dim i As Integer
        For i = 0 To count - 1
            chars(i) = Convert.ToChar(bytes(i + offset))
        Next

        ' Create a string from the char array
        Dim output As New String(chars)
        ' Replace all <BR> with <P>, in case-insensitive mode.
        output = Replace(output, "<b>", "<strong>", , , CompareMethod.Text)
        output = Replace(output, "</b>", "</strong>", , , CompareMethod.Text)

        ' Copy the string back into an array of chars.
        chars = output.ToCharArray
        Dim newBytes(chars.Length - 1) As Byte
        ' Copy the array of chars into an array of bytes.
        For i = 0 To chars.Length - 1
            newBytes(i) = Convert.ToByte(chars(i))
        Next

        ' Output the bytes.
        m_stream.Write(newBytes, 0, count)
    End Sub
End Class