ZipArchiveEntry.Open Method ()

.NET Framework (current version)

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Opens the entry from the zip archive.

Namespace:   System.IO.Compression
Assembly:  System.IO.Compression (in System.IO.Compression.dll)

public Stream Open()

Return Value

Type: System.IO.Stream

The stream that represents the contents of the entry.

Exception Condition

The entry is already currently open for writing.


The entry has been deleted from the archive.


The archive for this entry was opened with the Create mode, and this entry has already been written to.


The entry is either missing from the archive or is corrupt and cannot be read.


The entry has been compressed by using a compression method that is not supported.


The zip archive for this entry has been disposed.

You use this method to access the stream for an entry in a zip archive. After retrieving the stream, you can read from or write to the stream. When you write to the stream, the modifications you make to the entry will appear in the zip archive.

The following example shows how to create a new entry, open it with the Open method, and write to the stream.

using System;
using System.IO;
using System.IO.Compression;

namespace ConsoleApplication
    class Program
        static void Main(string[] args)
            using (FileStream zipToOpen = new FileStream(@"c:\users\exampleuser\", FileMode.Open))
                using (ZipArchive archive = new ZipArchive(zipToOpen, ZipArchiveMode.Update))
                    ZipArchiveEntry readmeEntry = archive.CreateEntry("Readme.txt");
                    using (StreamWriter writer = new StreamWriter(readmeEntry.Open()))
                            writer.WriteLine("Information about this package.");

Universal Windows Platform
Available since 8
.NET Framework
Available since 4.5
Portable Class Library
Supported in: portable .NET platforms
Windows Phone
Available since 8.1
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