Like to understand - Stream DataSet (of XML data) to ZIP file?

Question

i have similar kind of requirement where i need to save dataset data in multi part zip file. from this site i got a sample code
.NET - Stream DataSet (of XML data) to ZIP file? but few area is not clear.
the sample code as follows
// get connection to the database
var c1= new System.Data.SqlClient.SqlConnection(connstring1);
var da = new System.Data.SqlClient.SqlDataAdapter()
SelectCommand= new System.Data.SqlClient.SqlCommand(strSelect, c1)
DataSet ds1 = new DataSet();
// fill the dataset with the SELECT
da.Fill(ds1, "Invoices");
// write the XML for that DataSet into a zip file (split into 1mb chunks)
using(Ionic.Zip.ZipFile zip = new Ionic.Zip.ZipFile())
zip.MaxOutputSegmentSize = 1024*1024;
zip.AddEntry(zipEntryName, (name,stream) => ds1.WriteXml(stream) );
zip.Save(zipFileName);
how this word code Ionic they are using dotnet zip library ? tell me what is
Ionic
i guess this line zip.MaxOutputSegmentSize = 1024*1024; means each segment size would be 1mb ? am i right ?
this line is not clear
zip.AddEntry(zipEntryName, (name,stream) => ds1.WriteXml(stream) );
what is the meaning of this (name,stream) stream never declared but how they can use ?
tell me what is the meaning of this line zip.AddEntry(zipEntryName, (name,stream) => ds1.WriteXml(stream) ); what the code will do reading the above statement.
suppose if the above code save dataset data in 5 separate zip file then what name will be used for each segment?
if possible give me the code which will read all segment file and extract its content in a folder. thanks

Answer 1

Ionic is a 3rd party library which can be download by click on the shortcut where you got the code.  I don't recommend using compiled 3rd part software unless the source code is provided.  Codeplex solutions are usually very reliable.
Yes 1024 x 1024 is the 1mbyte size of the stream
The library is using a Linq syntax.  So  simple Linq uses something like this
.Select(x => x.ToString())  Where x is a variable name that can be any letter(s) you choose.  Select is part of an enumeration.  It is really just a shortcut instead of using a "FOR" statement.
The line zip is more complicated version of Linq.  It is using two parameters (name,stream).  I don't think the code actually works and you would have to look at the documentation at the codeplex website.
jdweng