extract 7zip in C# code

I need use 7zip in C#. Without console, just with 7zSharp.dll ? + I find some data here

http://7zsharp.codeplex.com/releases/view/10305 ,

but I don't know how to use it( - I could create .bat(.cmd) file, but I need throught dll file) Exactly: I need extract .7z file with key)

Download the standalone console version from 7zip.com and add it to your project.

You need those 3 Files added in the project:

1. 7za.exe
2. 7za.dll
3. 7zxa.dll

Don't forget to say Copy to Output Directory in it's preferences.

Extract an archive:

public void ExtractFile(string sourceArchive, string destination)
    {
        string zPath = "7za.exe"; //add to proj and set CopyToOuputDir
        try
        {
            ProcessStartInfo pro = new ProcessStartInfo();
            pro.WindowStyle = ProcessWindowStyle.Hidden;
            pro.FileName = zPath;
            pro.Arguments = string.Format("x \"{0}\" -y -o\"{1}\"", sourceArchive, destination);
            Process x = Process.Start(pro);
            x.WaitForExit();
        }
        catch (System.Exception Ex) {
            //handle error
        }
    }

Create an archive:

public void CreateZip(string sourceName, string targetArchive)
{
    ProcessStartInfo p = new ProcessStartInfo();
    p.FileName = "7za.exe";
    p.Arguments = string.Format("a -tgzip \"{0}\" \"{1}\" -mx=9", targetArchive, sourceName);
    p.WindowStyle = ProcessWindowStyle.Hidden;
    Process x = Process.Start(p);
    x.WaitForExit();
}

The authors of 7zip provide the LZMA SDK and good documentation which should be able to achieve what you want. The SDK includes C# code capable of compression / decompression.

Another option would be to use a something like C# (.NET) Interface for 7-Zip Archive DLLs

UPDATE: Another user asked a similar question here: How do I create 7-Zip archives with .NET? The answer has several of the same links I provided and a few more.