using SevenZip;
using System.Windows.Forms;
using System;

   class C7Z
   {
       public static void Compress7Z(string filePath, string outPath)
       {
           SevenZipCompressor.SetLibraryPath(String.Format(@"{0}\7z.dll", Application.StartupPath));
           SevenZipCompressor cmp = new SevenZipCompressor
                                        {
                                            ArchiveFormat = OutArchiveFormat.SevenZip,
                                            CompressionMethod = CompressionMethod.Lzma,
                                            CompressionMode = CompressionMode.Create,
                                            CompressionLevel = CompressionLevel.High,
                                            VolumeSize = 0
                                        };
           cmp.CompressFiles(outPath, filePath);
       }

   }

C7Z.Compress7Z(@"C:\test\test.txt", @"C:\test\test.7z");