File handling in .NET

Question

I have developed an application using VB.NET, Visual Studio 2008 and the SQL Server database. Now I want to ignore the database (it has 1 table as customer (name,password,hour,minute)) as I don't want my client to install SQL Server separately or other overheads.

I am planning to do the whole using file handling in VB.NET (manipulating the data in files itself, for example change username, password, etc.). As I am new I don't actually know the proper way and of course need assistance.

Answer 1

You might want to use SQLLite, which is an in-process DB. You could reuse most of your existing code and your client doesn't have to deal with the overhead of installing SQL Server.

Answer 2

You do not have to do this using files... You will lose the bascic functionality provided by a db such as simple INSERT/UPDATE/DELETE/QUERY

You could use a simple Database such as MS Access or SQLite

Edit

MS Access Connection string will depend on the version you are using, a little more detail on the possible version of Office/MS Access will help but

MS Access 2007:

Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\myFolder\myAccess2007file.accdb;Persist Security Info=False;

Prior to MS Access 2007

Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\mydatabase.mdb;User Id=admin;Password=;

For Ms Access you need to use OleDbConnection Class instead of SqlConnection Class as for Sql Server

Answer 3

Some people prefer to store simple data as XML. Then you can use LINQ or XPath to query the XML. I have also seen others use a strongly-typed DataSet and persist it to the HDD.

Answer 4

I'm not sure what file format you'd like to use for your flat files, but one easy option is to use XML. You can certainly generate your own format, but there's some easy tooling in VB.Net for reading and writing XML files.

To write an xml file:

Public Sub SaveAs(ByVal fileName As String)
    Dim writer As Xml.XmlWriter
    Dim settings As New Xml.XmlWriterSettings
    settings.Indent = True
    settings.CloseOutput = True
    writer = Xml.XmlWriter.Create(fileName, settings)

    writer.WriteStartElement("customer")

    writer.WriteStartElement("customerName")
    writer.WriteValue("customer #1")
    writer.WriteEndElement()

    writer.WriteEndElement()

    writer.Close()
End Sub

Reading from an XML document you can use some of the inline VB XML language features:

Public Sub Load(ByVal fileName as String)
    If Not IO.File.Exists(fileName) Then Throw New Exception("File not found.")
    Dim xDoc as XDocument

    Try 
        xDoc = XDocument.Load(fileName)
    Catch e as Xml.XmlException
        Throw New FileFormatException()
    End Try

    Dim customers = xDoc..<customer>
    For each customer in customers
        Dim customerName = customer.<customerName>.Value
        //'do something with the data
    Next

End Sub

Beth Massi has some good videos on working with XML files and data in VB