CreateEntry Method (String, CompressionLevel)
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ZipArchive.CreateEntry Method (String, CompressionLevel)

.NET Framework (current version)
 

Creates an empty entry that has the specified entry name and compression level in the zip archive.

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

public ZipArchiveEntry CreateEntry(
	string entryName,
	CompressionLevel compressionLevel
)

Parameters

entryName
Type: System.String

A path, relative to the root of the archive, that specifies the name of the entry to be created.

compressionLevel
Type: System.IO.Compression.CompressionLevel

One of the enumeration values that indicates whether to emphasize speed or compression effectiveness when creating the entry.

Return Value

Type: System.IO.Compression.ZipArchiveEntry

An empty entry in the zip archive.

Exception Condition
ArgumentException

entryName is Empty.

ArgumentNullException

entryName is null.

NotSupportedException

The zip archive does not support writing.

ObjectDisposedException

The zip archive has been disposed.

The entryName string should reflect the relative path of the entry you want to create within the zip archive. There is no restriction on the string you provide. However, if it is not formatted as a relative path, the entry is created, but you may get an exception when you extract the contents of the zip archive. If an entry with the specified name already exists in the archive, a second entry is created with the same name.

The value of the LastWriteTime property for the new entry is set to the current time. Set the compressionLevel parameter to Optimal if you want the file to be compressed as much as possible. Set the compressionLevel parameter to Fastest only if you are concerned that the compression operation will not complete quickly enough for your scenario.

The following example shows how to create an entry with the optimal compression level. It also writes to the new entry by using a 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\release.zip", FileMode.Open))
            {
                using (ZipArchive archive = new ZipArchive(zipToOpen, ZipArchiveMode.Update))
                {
                    ZipArchiveEntry readmeEntry = archive.CreateEntry("Readme.txt", CompressionLevel.Optimal);
                    using (StreamWriter writer = new StreamWriter(readmeEntry.Open()))
                    {
                            writer.WriteLine("Information about this package.");
                            writer.WriteLine("========================");
                    }
                }
            }
        }
    }
}

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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