Imports System
Imports System.ComponentModel
Imports System.IO
Imports System.Web
Imports System.Web.UI
Imports System.Web.HttpResponse

Namespace LozinskiWebScript

    Public Class RandomImage2 : Inherits Control
        '#CLASS: RandomImage2 - Version 1.0
        '#
        '#INSTALLATION INSTRUCTIONS:
        '#	1) Compile this VB .NET code and move the resulting dll file into your web project's "bin" directory.
        '#  2) In the aspx page you wish to have this control run, add in the appropriate "Register" directive.
        '#  Example: 
        '#      <%@ Register TagPrefix="LozinskiWebScript" Namespace="LozinskiRandomImage2.Lozinski" Assembly="LozinskiRandomImage2" %>
        '#  3) Add the control's tag to your ASPX page wherever you would like the random image to occur. 
        '#  You MUST supply the "ImageDirectory" property as a URL relative to the location of the aspx page.
        '#  The URL must have a trailing slash "/" character.
        '#  Example tag below given the above "Register":
        '#      <Lozinski:RANDOMIMAGE2 ImageDirectory="../random_images/" ID="RandomImage21" RUNAT="server" />
        '#
        '#TO ADD THE CONTROL TO YOUR VISUAL STUDIO TOOLBOX:
        '#  1) Select "File | New Project"
        '#  2)  Make sure "VB Class" is slected. Change the default name
        '#          to "RandomImage2.vb", select the location, and
        '#          select "close solution".  
        '#  3) Click "ok".
        '#  3) Copy and paste this code into your new class file.
        '#  4) Compile this file.
        '#  5) Open up your web project with the aspx forms you would like
        '#      to have the random images on.
        '#  6) Select "Project | Add Reference"
        '#  7) Click the "browse" button. Find the location of the
        '#      LozinskiRandomImage2.dll file, select the file,
        '#      and click "ok".
        '#  8) You should now see it in your "solution explorer".
        '#  9) In the design view to any of your aspx web forms, right click
        '#      within your toolbox and select "add/remove items".
        '#  10) Click "browse", select the LozinskiRandomImage2.dll 
        '#      file, and click "ok". 
        '#  11) It should now be in your toolbox! Just drag and drop
        '#      like any other tool. Enjoy! :)
        '#  
        '#REQUIREMENTS:
        '#  1) Windows 2000 Server or later
        '#  2) IIS 5.0 or later
        '#  3) .NET Framework >= 1.1
        '#
        '#ABOUT THIS SCRIPT:
        '#	This is a very simple .NET script. All it does is grab a 
        '#random image from a directory and print the name within the associated
        '#HTML IMG tag. This code assumes the files stored in the
        '#directory are actual images such as jpgs, gifs, etc. 
        '#
        '#HISTORY:
        '#	07/30/05	1.0	Original release
        '#
        '#AUTHOR:
        '#	http://www.davelozinski.com/scripts
        '#
        '#Global class variable which holds the location of the random images.
        Private IMAGE_DIRECTORY As String

        <Description("A relative URL to the folder location containing the random images. Cannot be blank and MUST end with a trailing slash ""/"" character.")> _
        Public Property ImageDirectory() As String
            '#This value needs to be set in order for this control to work.
            Get
                Return Me.IMAGE_DIRECTORY
            End Get

            Set(ByVal Value As String)
                If (Value = "") Then
                    Throw New ArgumentException("""ImageDirectory"" cannot be an empty string.")
                ElseIf (Not Value.EndsWith("/")) Then
                    Throw New ArgumentException("""" & Value & """ should have a trailing slash ""/"" character.")
                Else
                    Me.IMAGE_DIRECTORY = Value
                End If
            End Set
        End Property

        Protected Overrides Sub Render(ByVal output As System.Web.UI.HtmlTextWriter)
            '#Render the HTML IMG tag, or the textual message if
            '#no files are found.
            Dim Images() As String  '#Holds the list of images to choose randomly from.
            Dim ReturnStr As String '#Either the IMG tag or message to be returned.
            Dim tempString As String '#Holds the list of images within the directory
            Dim dir As DirectoryInfo

            If (Not Directory.Exists(HttpContext.Current.Server.MapPath(Me.IMAGE_DIRECTORY))) Then
                Throw New ArgumentException("""" & Me.IMAGE_DIRECTORY & """ does not appear to be a valid directory.")
            Else
                dir = New DirectoryInfo(HttpContext.Current.Server.MapPath(Me.IMAGE_DIRECTORY))
                For Each fi As FileInfo In dir.GetFiles("*.*")
                    tempString = tempString & fi.Name & ","
                Next
                If (Len(tempString) > 0) Then
                    tempString = tempString & "," '#Puts a double comma to demark the end
                    tempString = StrReverse(tempString)
                    tempString = Replace(tempString, ",,", "", 1)
                    tempString = StrReverse(tempString)
                    Images = Split(tempString, ",")
                    Randomize()
                    ReturnStr = "<IMG SRC=""" & Me.IMAGE_DIRECTORY & Images(CInt((UBound(Images) - LBound(Images)) * Rnd() + LBound(Images))) & """ ALT="""">" & vbCrLf
                Else
                    ReturnStr = "No random images located in """ & Me.IMAGE_DIRECTORY & """" & vbCrLf
                End If
                output.Write(ReturnStr)
            End If
        End Sub

    End Class

End Namespace