DotNetZip - ASP.NET VB Example

ASP.NET Example in VB

Here's an Example ASP.NET page, using VB, that dynamically creates a zip file and saves it to Response.OutStream. From the browser, the user will be prompted with the familiar download dialog box, allowing Open, Save, or Cancel of the generated zip file.




<%@ Page
    Language="VB"
    Debug="true"
%>

<%@ Import Namespace="System.Text" %>
<%@ Import Namespace="System.IO" %>
<%@ Import Namespace="Ionic.Zip" %>
<%@ Import Namespace="System.Collections.Generic" %>

<script language="VB" runat="server">

' ZipExample.aspx
'
' This .aspx page demonstrates how to use the DotNetZip library from within ASP.NET.
'
' To run it,
'  1. drop the Ionic.Zip.dll into the \bin directory of your asp.net app
'  2. create a subdirectory called "fodder" in your web app directory.
'  3. copy into that directory a variety of random files.
'  4. insure your web.config is properly set up (See below)
'
'
' notes:
'  This requies the .NET Framework 3.5 - because it uses the ListView control that is
'  new for ASP.NET in the .NET Framework v3.5.
'
'  To use this control, you must add the new web controls.  Also, you must use the v3.5 compiler.
'  Here's an example web.config that works with this aspx file:
'
'    <configuration>
'      <system.web>
'        <trust level="Medium" />
'        <compilation defaultLanguage="c#" />
'        <pages>
'          <controls>
'            <add tagPrefix="asp" namespace="System.Web.UI.WebControls"
'                 assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
'          </controls>
'        </pages>
'      </system.web>
'      <system.codedom>
'        <compilers>
'          <compiler language="c#;cs;csharp"
'                extension=".cs"
'                warningLevel="4"
'                type="Microsoft.CSharp.CSharpCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
'            <providerOption name="CompilerVersion" value="v3.5" />
'            <providerOption name="WarnAsError" value="false" />
'          </compiler>
'
'          <compiler language="vb;vbs;visualbasic;vbscript"
'                    extension=".vb"
'                    warningLevel="4"
'                    type="Microsoft.VisualBasic.VBCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
'            <providerOption name="CompilerVersion" value="v3.5" />
'            <providerOption name="OptionInfer" value="false" />
'            <providerOption name="WarnAsError" value="false" />
'          </compiler>
'
'      </system.codedom>
'    </configuration>
'
'


Dim width as String = "100%"

Public Sub Page_Load (ByVal sender As Object, ByVal e As System.EventArgs)
    Try
        If Not ( Page.IsPostBack ) Then
            ' populate the dropdownlist
            ' must have a directory called "fodder" in the web app
            Dim homeDir as String = Server.MapPath(".")
            Dim sMappedPath as  String= Server.MapPath("fodder")

            Dim fqFilenames As New List(Of String)(System.IO.Directory.GetFiles(sMappedPath))

            Dim filenames as List(Of String) = _
                fqFilenames.ConvertAll (Function(s) s.Replace(sMappedPath & "\", ""))

            ErrorMessage.InnerHtml = ""

            FileListView.DataSource = filenames
            FileListView.DataBind()
        End If

    Catch
        ' Ignored
    End Try

End Sub



Public Sub btnGo_Click (ByVal sender As System.Object, ByVal e As System.EventArgs)

    ErrorMessage.InnerHtml =""   ' debugging only
    Dim filesToInclude as New System.Collections.Generic.List(Of String)()
    Dim sMappedPath as String= Server.MapPath("fodder")
    Dim source As DataKeyArray= FileListView.DataKeys

    For Each item As ListViewDataItem in FileListView.Items

        Dim chkbox As CheckBox= CType(item.FindControl("include"), CheckBox)
        Dim lbl As Label = CType(item.FindControl("label"), Label)

        If Not (chkbox Is Nothing  OR  lbl Is Nothing) Then
            If (chkbox.Checked) Then
                ErrorMessage.InnerHtml = ErrorMessage.InnerHtml & _
                        String.Format("adding file: {0}<br/>\n", lbl.Text)
                filesToInclude.Add(System.IO.Path.Combine(sMappedPath,lbl.Text))
            End If
        End If
    Next

    If (filesToInclude.Count=0) Then
        ErrorMessage.InnerHtml = ErrorMessage.InnerHtml & "You did not select any files?<br/>\n"
    Else
        Response.Clear
        Response.BufferOutput= false

        Dim enc as Ionic.Zip.EncryptionAlgorithm = Ionic.Zip.EncryptionAlgorithm.None
        If (chkUseAes.Checked) Then
            enc = EncryptionAlgorithm.WinZipAes256
        End If

        Dim c As System.Web.HttpContext = System.Web.HttpContext.Current
        Dim ReadmeText As String= String.Format("README.TXT\n\nHello!\n\n" & _
                                         "This is a zip file that was dynamically generated at {0}\n" & _
                                         "by an ASP.NET Page running on the machine named '{1}'.\n" & _
                                         "The server type is: {2}\n" & _
                                         "The password used: {3}\n", _
                                         "Encryption: {4}\n", _
                                         System.DateTime.Now.ToString("G"), _
                                         System.Environment.MachineName, _
                                         c.Request.ServerVariables("SERVER_SOFTWARE"), _
                                         tbPassword.Text, _
                                         enc.ToString )
        Dim archiveName as String= String.Format("archive-{0}.zip", DateTime.Now.ToString("yyyy-MMM-dd-HHmmss"))
        Response.ContentType = "application/zip"
        Response.AddHeader("content-disposition", "filename=" + archiveName)

        Using zip as new ZipFile()
            ' the Readme.txt file will not be password-protected.
            zip.AddEntry("Readme.txt", ReadmeText, Encoding.Default)
            If Not String.IsNullOrEmpty(tbPassword.Text) Then
                zip.Password = tbPassword.Text
                zip.Encryption = enc
            End If

            ' filesToInclude is a string[] or List<String>
            zip.AddFiles(filesToInclude, "files")

            zip.Save(Response.OutputStream)
        End Using
        Response.Close

    End If

End Sub


</script>



<html>
  <head>
    <link rel="stylesheet" href="style/basic.css">
  </head>

  <body>

    <form id="Form" runat="server">

      <h3> <span id="Title" runat="server" />Zip Files from ASP.NET </h3>

      <p>This page uses the .NET Zip library (see <a
      href="http://DotNetZip.codeplex.com">http://DotNetZip.codeplex.com/</a>)
      to dynamically create a zip archive, and then download it to the
      browser through Response.OutputStream.  This page is implemented
      in VB.NET.</p>

      <span class="SampleTitle"><b>Check the boxes to select the files, set a password if you like,
      then click the button to zip them up.</b></span>
      <br/>
      <br/>
      Password: <asp:TextBox id="tbPassword" Password='true' Text="" AutoPostBack runat="server"/>
      <span style="color:Red">(Optional)</span>
      <br/>
      <br/>
      Use AES?: <asp:CheckBox id="chkUseAes" AutoPostBack runat="server"/>
      <br/>
      <br/>
      <asp:Button id="btnGo" Text="Zip checked files" AutoPostBack OnClick="btnGo_Click" runat="server"/>

      <br/>
      <br/>
      <span style="color:red" id="ErrorMessage" runat="server"/>
      <br/>

      <asp:ListView ID="FileListView" runat="server">

        <LayoutTemplate>
          <table>
            <tr ID="itemPlaceholder" runat="server" />
          </table>
        </LayoutTemplate>

        <ItemTemplate>
          <tr>
            <td><asp:Checkbox ID="include" runat="server"/></td>
            <td><asp:Label id="label" runat="server" Text="<%# Container.DataItem %>" /></td>
          </tr>
        </ItemTemplate>

        <EmptyDataTemplate>
          <div>Nothing to see here...</div>
        </EmptyDataTemplate>

      </asp:ListView>


    </form>

  </body>

</html>