Using XML as a storgae option in a smart device application.

Question

Hello i am trying to develop a small pocket pc smart device application in vb.net i want to read some simple data into my application from another location. Somenone i know directed me to this page at msdn: http://msdn.microsoft.com/library/d...tcpctfrmwrk.asp but i must admit i think the is far more advanced than i require(??) i have not found it very useful as it is it far beyond what i have ever dealt with before. I simply want to read-in from an external file (of some type) called products a few records say 10 each with 10 fields and then place these in an array. e.g. PRODUCTS Tea 75 cents 168 boxes Coffee 89 cents 134 boxes Bread 45 cents 50 loaves Then in vb.net this would become PRODUCTS{tea 75 cents 168 boxes etc etc} does anyone know how xml could be simply applied to achieve this??

MythicalMe · Answer

This is my third attempt at posting this so bear with me. I am suggesting that instead of using your array that you instead use the dataset. The dataset is a container for data. Arrays will only take you so far. If you want to transport that data around either to a database XML file RSS feed or whatever the dataset will help you. There is a little bit of a learning curve in using it and you really should have a tutorial or manual to guide you through the basic concepts. Simply a dataset is a container with one or more datatables and datarelations. A datatable consists of datacolumns that define the datatypes in a datarow. A datarow contains the actual data. The interesting thing about datasets is that the data is stored internally in XML format. This is why reading and writing to an XML file is so easy. It is simply streaming the data from memory to file and vice-versa. Poke around on the MSDN help system for examples of how to create and use the dataset. There are a lot of good examples that space and time doesn't afford here.

kate 0 · Answer

I must admit your code has lost me somewhat currently i hard code the intended data from my text file into an array. So are you suggesting that now i create a .xml file and then use the above methods? Will this go into an array also? Or not? I have further developed my system based upon the data being in a 2d array im not sure how a dataset works or how it will affect my application.

MythicalMe · Answer

You don't need to access the data tab. Do it in code. Here is an example from the MSDN help documentation that does what you're asking to do: Private Const AUTHORSXML As String = \Samples\VB.NET\AuthorsDB.xml We then declare a DataSet: Private dsAuthors As System.Data.DataSet Now we're ready to load the DataSet from the XML file using the ReadXml method: Private Sub loadXMLData() dsAuthors = New DataSet(AuthorsDB) Try Dim fs As New FileStream(AUTHORSXML FileMode.Open) Dim xr As New XmlTextReader(fs) dsAuthors.ReadXml(xr) xr.Close() fs.Close() Catch e As System.IO.FileNotFoundException MessageBox.Show(File  & AUTHORSXML &  not found.) Catch e As XmlException MessageBox.Show(XmlException occured) End Try End Sub And here's the Form's Load event which calls the loading routine and then iterates through the DataSet adding each row to the ListView control: Private Sub frmAuthors_Load(ByVal sender As System.Object _ ByVal e As System.EventArgs) Handles MyBase.Load loadXMLData() Dim dr As DataRow Dim it As ListViewItem For Each dr In dsAuthors.Tables(Authors).Rows it = New ListViewItem(dr(id).ToString()) it.SubItems.Add(dr(name).ToString()) it.SubItems.Add(dr(phone).ToString()) lvCompanies.Items.Add(it) Next End Sub

kate 0 · Answer

But you cannot access the data tab in the tool box when developing with smart device applications????????? Hence how do you work with data sets?

MythicalMe · Answer

Set up a dataset and use the ReadXML and WriteXML functions. It's as easy as that.