CompressionLevel Enum

Definition

Namespace:

System.IO.Compression

Assembly:

System.IO.Compression.dll

Specifies values that indicate whether a compression operation emphasizes speed or compression size.

public enum class CompressionLevel

public enum CompressionLevel

type CompressionLevel = 

Public Enum CompressionLevel

Inheritance

Object

ValueType

Enum

CompressionLevel

Fields

Name	Value	Description
Optimal	0	The compression operation should optimally balance compression speed and output size.
Fastest	1	The compression operation should complete as quickly as possible, even if the resulting file is not optimally compressed.
NoCompression	2	No compression should be performed on the file.
SmallestSize	3	The compression operation should create output as small as possible, even if the operation takes a longer time to complete.

Remarks

Compression operations usually involve a tradeoff between the speed and the effectiveness of compression. You use the CompressionLevel enumeration to indicate which factor is more important in your development scenario: the time to complete the compression operation or the size of the compressed file. These values do not correspond to specific compression levels; the object that implements compression determines how to handle them.

The following methods of the DeflateStream, GZipStream, ZipArchive, ZipFile, and ZipFileExtensions classes include a parameter named compressionLevel that lets you specify the compression level:

• DeflateStream.DeflateStream(Stream, CompressionLevel)

• DeflateStream.DeflateStream(Stream, CompressionLevel, Boolean)

• GZipStream.GZipStream(Stream, CompressionLevel)

• GZipStream.GZipStream(Stream, CompressionLevel, Boolean)

• ZipArchive.CreateEntry(String, CompressionLevel)

• ZipFile.CreateFromDirectory(String, String, CompressionLevel, Boolean)

• ZipFileExtensions.CreateEntryFromFile(ZipArchive, String, String, CompressionLevel)

Examples

The following example shows how to set the compression level when creating a zip archive by using the ZipFile class.

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

namespace ConsoleApplication
{
    class Program
    {
        static void Main(string[] args)
        {
            string startPath = @"c:\example\start";
            string zipPath = @"c:\example\result.zip";

            ZipFile.CreateFromDirectory(startPath, zipPath, CompressionLevel.Fastest, true);
        }
    }
}

Imports System.IO
Imports System.IO.Compression

Module Module1

    Sub Main()
        Dim startPath As String = "c:\example\start"
        Dim zipPath As String = "c:\example\result.zip"

        ZipFile.CreateFromDirectory(startPath, zipPath, CompressionLevel.Fastest, True)
    End Sub

End Module