XceedZipLib.XceedZip zip = new XceedZipLib.XceedZipClass();

zip.License( @"your license key" ); 

// Specify which files will be added to be unzipped.
// Setting this property to an empty string will
// extract all the files from the zip file
zip.FilesToProcess = string.Empty; 

// Specify the name and location of the zip file.
zip.ZipFilename = @"d:\fonts.zip"; 

// Specify the location where the files are to be unzipped.
zip.UnzipToFolder =  @"c:\test"; 

// Unzip the files
XceedZipLib.xcdError result = zip.Unzip();

MessageBox.Show( zip.GetErrorDescription( XceedZipLib.xcdValueType.xvtError, ( int )result ) );