Introduction
The ZipFile class lives in the System.IO.Compression namespace. It can be used to read from, and write to Zip files.
Remarks
-
You can also use a MemoryStream instead of a FileStream.
-
Exceptions
| Exception | Condition |
|---|---|
| ArgumentException | The stream has already been closed, or the capabilities of the stream does not match the mode (eg: trying to write to a read only stream) |
| ArgumentNullException | input stream is null |
| ArgumentOutOfRangeException | mode has an invalid value |
| InvalidDataException | See list below |
When a InvalidDataException is thrown, it can have 3 causes:
- The contents of the stream could not be interpreted as a zip archive
- mode is Update and an entry is missing from the archive or is corrupt and cannot be read
- mode is Update and an entry is too large to fit into memory
All information has been taken from this MSDN page
Listing ZIP contents
This snippet will list all the filenames of a zip archive. The filenames are relative to the zip root.
using (FileStream fs = new FileStream("archive.zip", FileMode.Open))
using (ZipArchive archive = new ZipArchive(fs, ZipArchiveMode.Read))
{
for (int i = 0; i < archive.Entries.Count; i++)
{
Console.WriteLine($"{i}: {archive.Entries[i]}");
}
}
Extracting files from ZIP files
Extracting all the files into a directory is very easy:
using (FileStream fs = new FileStream("archive.zip", FileMode.Open))
using (ZipArchive archive = new ZipArchive(fs, ZipArchiveMode.Read))
{
archive.ExtractToDirectory(AppDomain.CurrentDomain.BaseDirectory);
}
When the file already exists, a System.IO.IOException will be thrown.
Extracting specific files:
using (FileStream fs = new FileStream("archive.zip", FileMode.Open))
using (ZipArchive archive = new ZipArchive(fs, ZipArchiveMode.Read))
{
// Get a root entry file
archive.GetEntry("test.txt").ExtractToFile("test_extracted_getentries.txt", true);
// Enter a path if you want to extract files from a subdirectory
archive.GetEntry("sub/subtest.txt").ExtractToFile("test_sub.txt", true);
// You can also use the Entries property to find files
archive.Entries.FirstOrDefault(f => f.Name == "test.txt")?.ExtractToFile("test_extracted_linq.txt", true);
// This will throw a System.ArgumentNullException because the file cannot be found
archive.GetEntry("nonexistingfile.txt").ExtractToFile("fail.txt", true);
}
Any of these methods will produce the same result.
Updating a ZIP file
To update a ZIP file, the file has to be opened with ZipArchiveMode.Update instead.
using (FileStream fs = new FileStream("archive.zip", FileMode.Open))
using (ZipArchive archive = new ZipArchive(fs, ZipArchiveMode.Update))
{
// Add file to root
archive.CreateEntryFromFile("test.txt", "test.txt");
// Add file to subfolder
archive.CreateEntryFromFile("test.txt", "symbols/test.txt");
}
There is also the option to write directly to a file within the archive:
var entry = archive.CreateEntry("createentry.txt");
using(var writer = new StreamWriter(entry.Open()))
{
writer.WriteLine("Test line");
}
