Installed .Net 4.5 but can't use ZipFile class in Visual C#

问题

I'm kind of a newbie to Visual Studio programming.

I recently upgraded .Net 4.0 to 4.5 in order to use the ZipFile class under System.IO.Compression, but after the installation completed, Visual Studio (I'm using 2012) still cannot recognize ZipFile as a class name.

I've made sure that .Net 4.5 appears in Control Panel programs list and my C# solution sets .Net Framework 4 as the target framework.

Could someone help me figure this out?

回答1:

See ZipFile Class on MSDN. It shows the required framework version is 4.5. Once the framework version is fixed check you have added a reference to the System.IO.Compression.FileSystem.dll assembly and added a using System.IO.Compression directive to your class.

回答2:

You also need to reference the System.IO.Compression.FileSystem.dll assembly.

回答3:

Just to further clarify the previous answers, here's how to add the references manually to a Web.config:

<configuration>
  <system.web>
    <compilation targetFramework="4.5">
      <assemblies>
        <add assembly="System.IO.Compression, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
        <add assembly="System.IO.Compression.FileSystem, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
      </assemblies>
    </compilation>
  </system.web>
</configuration>

Or to a *.csproj:

<Project ...>
  <ItemGroup>
    <Reference Include="System.IO.Compression, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089, processorArchitecture=MSIL" />
    <Reference Include="System.IO.Compression.FileSystem, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089, processorArchitecture=MSIL" />
  </ItemGroup>
</Project>

The files can be found in C:\Windows\Microsoft.NET\assembly\GAC_MSIL\ and the subfolders contain the necessary info on version, culture and PublicKeyToken as well.

回答4:

You need to change the target framework of the current project from .Net 4 to .Net 4.5.

回答5:

New features in .NET 4.5

Zip compression improvements to reduce the size of a compressed file. See the System.IO.Compression namespace.

Add System.IO.Compression assembly as reference to your project. You may also want to reference System.IO.Compression.FileSystem assembly to access three extension methods (from the ZipFileExtensions class) for the ZipArchive class: CreateEntryFromFile, CreateEntryFromFile, and ExtractToDirectory. These extension methods enable you to compress and decompress the contents of the entry to a file.

Sample

const string zipFilePath = @"C:\apps\Sample Pictures.zip";

using (FileStream zipFileToOpen = new FileStream(zipFilePath, FileMode.Open))
using (ZipArchive archive = new ZipArchive(zipFileToOpen, ZipArchiveMode.Read)) {

        foreach (var zipArchiveEntry in archive.Entries)
            Console.WriteLine(
                "FullName of the Zip Archive Entry: {0}", zipArchiveEntry.FullName
            );
}

References:
http://msdn.microsoft.com/en-us/library/ms171868.aspx
http://www.tugberkugurlu.com/archive/net-4-5-to-support-zip-file-manipulation-out-of-the-box

回答6:

For Windows Phone 8.1, use NuGet to add the Microsoft Compression package to your project and reference it.

If you had an older WP8 project you may have been using a different package that would create conflicts with the System.IO.Compression dll that is part of the .NET 4.5 that comes with WP8.1. You need to get rid of that and use Microsoft Compression which works harmoniously with .NET 4.5. That's how I got here!

回答7:

In my case I needed to manually delete all dll references that started with System.IO.Compression and then add one by one the needed ones (System.IO.Compression.FileSystem, etc.) even though I only wrote a single using statement

using System.IO.Compression;

I hope this helps someone

来源：https://stackoverflow.com/questions/14218602/installed-net-4-5-but-cant-use-zipfile-class-in-visual-c-sharp

标签

.net

visual-studio-2012

compression

zipfile