I didn't find "ZipFile" class in the "System.IO.Compression" namespace

I can't use "Zipfile" class in the name space "System.IO.Compression" my code is :

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";
            string extractPath = @"c:\example\extract";

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

            ZipFile.ExtractToDirectory(zipPath, extractPath);
        }
    }
}

the error is :

The name 'zipfile' does not exist in the current context

How I can solve it ?

You need an extra reference for this; the most convenient way to do this is via the NuGet package System.IO.Compression.ZipFile

<!-- Version here correct at time of writing, but please check for latest -->
<PackageReference Include="System.IO.Compression.ZipFile" Version="4.3.0" />

If you are working on .NET Framework without NuGet, you need to add a dll reference to the assembly, "System.IO.Compression.FileSystem.dll" - and ensure you are using at least .NET 4.5 (since it doesn't exist in earlier frameworks).

For info, you can find the assembly and .NET version(s) from MSDN

For those who are green programmers in .NET, to add the DLL reference as MarcGravell noted, you follow these steps:

To add a reference in Visual C#

1. In Solution Explorer, right-click the project node and click Add Reference.
2. In the Add Reference dialog box, select the tab indicating the type of component you want to reference.
3. Select the components you want to reference, and then click OK.

From the MSDN Article, How to: Add or Remove References By Using the Add Reference Dialog Box.

you can use an external package if you cant upgrade to 4.5. One such is Ionic.Zip.dll from DotNetZipLib.

using Ionic.Zip;

you can download it here, its free. http://dotnetzip.codeplex.com/

Just go to References and add "System.IO.Compression.FileSystem".

A solution that helped me: Go to Tools > NuGet Package Manager > Manage NuGet Packaged for Solution... > Browse > Search for System.IO.Compression.ZipFile and install it

In solution explorer, right-click References, then click to expand assemblies, find System.IO.Compression.FileSystem and make sure it's checked. Then you can use it in your class - using System.IO.Compression;

Add Reference Assembly Screenshot

System.IO.Compression is now available as a nuget package maintained by Microsoft.

To use ZipFile you need to download System.IO.Compression.ZipFile nuget package.

I know this is an old thread, but I just cannot steer away from posting some useful info on this. I see the Zip question come up a lot and this answers nearlly most of the common questions.

To get around framework issues of using 4.5+... Their is a ZipStorer class created by jaime-olivares: https://github.com/jaime-olivares/zipstorer, he also has added an example of how to use this class as well and has also added an example of how to search for a specific filename as well.

And for reference on how to use this and iterate through for a certain file extension as example you could do this:

#region
/// <summary>
/// Custom Method - Check if 'string' has '.png' or '.PNG' extension.
/// </summary>
static bool HasPNGExtension(string filename)
{
    return Path.GetExtension(filename).Equals(".png", StringComparison.InvariantCultureIgnoreCase)
        || Path.GetExtension(filename).Equals(".PNG", StringComparison.InvariantCultureIgnoreCase);
}
#endregion

private void button1_Click(object sender, EventArgs e)
{
    //NOTE: I recommend you add path checking first here, added the below as example ONLY.
    string ZIPfileLocationHere = @"C:\Users\Name\Desktop\test.zip";
    string EXTRACTIONLocationHere = @"C:\Users\Name\Desktop";

    //Opens existing zip file.
    ZipStorer zip = ZipStorer.Open(ZIPfileLocationHere, FileAccess.Read);

    //Read all directory contents.
    List<ZipStorer.ZipFileEntry> dir = zip.ReadCentralDir();

    foreach (ZipStorer.ZipFileEntry entry in dir)
    {
        try
        {
            //If the files in the zip are "*.png or *.PNG" extract them.
            string path = Path.Combine(EXTRACTIONLocationHere, (entry.FilenameInZip));
            if (HasPNGExtension(path))
            {
                //Extract the file.
                zip.ExtractFile(entry, path);
            }
        }
        catch (InvalidDataException)
        {
            MessageBox.Show("Error: The ZIP file is invalid or corrupted");
            continue;
        }
        catch
        {
            MessageBox.Show("Error: An unknown error ocurred while processing the ZIP file.");
            continue;
        }
    }
    zip.Close();
}

Add System.IO.Compression.ZipFile as nuget reference it is working

The issue here is that you just Added the reference to System.IO.Compression it is missing the reference to System.IO.Compression.Filesystem.dll

And you need to do it on .net 4.5 or later (because it doesn't exist on older versions).

I just posted a script on TechNet Maybe somebody would find it useful it requires .net 4.5 or 4.7

https://gallery.technet.microsoft.com/scriptcenter/Create-a-Zip-file-from-a-b23a7530