Read Method (fileName, options)

DotNetZip

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Ionic Zip Library v1.9.1.6 Read Method (fileName, options)

Reads a zip file archive from the named filesystem file using the specified options.

Declaration Syntax

Visual Basic

Visual C++

public static ZipFile Read(
	string fileName,
	ReadOptions options
)

Public Shared Function Read ( _
	fileName As String, _
	options As ReadOptions _
) As ZipFile

public:
static ZipFile^ Read(
	String^ fileName, 
	ReadOptions^ options
)

Parameters

fileName (String): The name of the zip archive to open. This can be a fully-qualified or relative pathname.

options (ReadOptions): The set of options to use when reading the zip file.

Return Value

The ZipFile instance read from the zip archive.

Remarks

This version of the Read() method allows the caller to pass in a TextWriter an Encoding, via an instance of the ReadOptions class. The ZipFile is read in using the specified encoding for entries where UTF-8 encoding is not explicitly specified.

Examples

This example shows how to read a zip file using the Big-5 Chinese code page (950), and extract each entry in the zip file, while sending status messages out to the Console.

For this code to work as intended, the zipfile must have been created using the big5 code page (CP950). This is typical, for example, when using WinRar on a machine with CP950 set as the default code page. In that case, the names of entries within the Zip archive will be stored in that code page, and reading the zip archive must be done using that code page. If the application did not use the correct code page in ZipFile.Read(), then names of entries within the zip archive would not be correctly retrieved.

CopyC#

string zipToExtract = "MyArchive.zip";
string extractDirectory = "extract";
var options = new ReadOptions
{
  StatusMessageWriter = System.Console.Out,
  Encoding = System.Text.Encoding.GetEncoding(950)
};
using (ZipFile zip = ZipFile.Read(zipToExtract, options))
{
  foreach (ZipEntry e in zip)
  {
     e.Extract(extractDirectory);
  }
}

CopyVB.NET

Dim zipToExtract as String = "MyArchive.zip"
Dim extractDirectory as String = "extract"
Dim options as New ReadOptions
options.Encoding = System.Text.Encoding.GetEncoding(950)
options.StatusMessageWriter = System.Console.Out
Using zip As ZipFile = ZipFile.Read(zipToExtract, options)
    Dim e As ZipEntry
    For Each e In zip
     e.Extract(extractDirectory)
    Next
End Using

Examples

This example shows how to read a zip file using the default code page, to remove entries that have a modified date before a given threshold, sending status messages out to a StringWriter.

CopyC#

var options = new ReadOptions
{
  StatusMessageWriter = new System.IO.StringWriter()
};
using (ZipFile zip =  ZipFile.Read("PackedDocuments.zip", options))
{
  var Threshold = new DateTime(2007,7,4);
  // We cannot remove the entry from the list, within the context of
  // an enumeration of said list.
  // So we add the doomed entry to a list to be removed later.
  // pass 1: mark the entries for removal
  var MarkedEntries = new System.Collections.Generic.List<ZipEntry>();
  foreach (ZipEntry e in zip)
  {
    if (e.LastModified < Threshold)
      MarkedEntries.Add(e);
  }
  // pass 2: actually remove the entry.
  foreach (ZipEntry zombie in MarkedEntries)
     zip.RemoveEntry(zombie);
  zip.Comment = "This archive has been updated.";
  zip.Save();
}
// can now use contents of sw, eg store in an audit log

CopyVB.NET

Dim options as New ReadOptions
options.StatusMessageWriter = New System.IO.StringWriter
Using zip As ZipFile = ZipFile.Read("PackedDocuments.zip", options)
    Dim Threshold As New DateTime(2007, 7, 4)
    ' We cannot remove the entry from the list, within the context of
    ' an enumeration of said list.
    ' So we add the doomed entry to a list to be removed later.
    ' pass 1: mark the entries for removal
    Dim MarkedEntries As New System.Collections.Generic.List(Of ZipEntry)
    Dim e As ZipEntry
    For Each e In zip
        If (e.LastModified < Threshold) Then
            MarkedEntries.Add(e)
        End If
    Next
    ' pass 2: actually remove the entry.
    Dim zombie As ZipEntry
    For Each zombie In MarkedEntries
        zip.RemoveEntry(zombie)
    Next
    zip.Comment = "This archive has been updated."
    zip.Save
End Using
' can now use contents of sw, eg store in an audit log

Exceptions

Exception	Condition
Exception	Thrown if the zipfile cannot be read. The implementation of this method relies on System.IO.File.OpenRead, which can throw a variety of exceptions, including specific exceptions if a file is not found, an unauthorized access exception, exceptions for poorly formatted filenames, and so on.