VB.NET Serialize Hashtable (nonbinary)

Posted on 2009-04-15
Last Modified: 2013-11-08
I'm very new to VB. Only been using it for about a week. I've got about 9 years of Perl behind me so I can understand concepts perfectly, I just don't know the methods for VB or the 'lingo', be gentle lol.

I've got a basic hash setup something like key: blahblah, value: 8752.  I'm trying to figure out how to drop that out to human-readable .xml. (The data was originally .INI, if that helps at all) Keys are always strings, values are always integers, no chance of any duplicates, ever.

Any help is greatly appreciated as my friend's comment was waay out of my league, creating classes with properties and whatnot. Sounds like rolling my own form of a Hashtable.
Question by:Craz3d
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 4
  • 2
LVL 47

Expert Comment

by:Wayne Taylor (webtubbs)
ID: 24155106
Depending on the flavour of XML you want, I have two options....
LVL 47

Expert Comment

by:Wayne Taylor (webtubbs)
ID: 24155109
Use the XmlSerializer object....
    Public Shared Function HashToXml(ByVal hash As Hashtable) As String
        Dim entries As New List(Of Entry)(hash.Count)
        For Each key As Object In hash.Keys
            entries.Add(New Entry(key, hash(key)))
        Dim sb As New Text.StringBuilder
        Dim writer As New System.IO.StringWriter(sb)
        Dim serializer As New XmlSerializer(GetType(List(Of Entry)))
        serializer.Serialize(writer, entries)
        Return sb.ToString
    End Function
    Public Class Entry
        Public Key As Object
        Public Value As Object
        Public Sub New()
            'nothing here
        End Sub
        Public Sub New(ByVal key As Object, ByVal value As Object)
            Me.Key = key
            Me.Value = value
        End Sub
    End Class

Open in new window

LVL 47

Accepted Solution

Wayne Taylor (webtubbs) earned 500 total points
ID: 24155115
2) Create a DataSet, populate it with the HashTable data, then use the DataSet.WriteToXML method...
    Public Shared Function HashToXML(ByVal ht As Hashtable) As String
        Dim sb As New Text.StringBuilder
        Dim sr As New IO.StringWriter(sb)
        Dim ds As New DataSet("HashToXML")
        Dim dt As New DataTable("Item")
        For Each key As Object In ht.Keys
            dt.Rows.Add(New Object() {key.ToString, ht(key).ToString})
        Return sb.ToString
    End Function

Open in new window

The Orion Papers

Are you interested in becoming an AWS Certified Solutions Architect?

Discover a new interactive way of training for the exam.


Author Comment

ID: 24155324
Tried both methods, the first was a bit more obfuscated than I'd like. The second didn't actually put out any newlines in the file but (unless I'm mistaken) I can just do that by hand, it's no biggy.

How might I pull them back into a hashtable?
LVL 47

Expert Comment

by:Wayne Taylor (webtubbs)
ID: 24155420
>>The second didn't actually put out any newlines in the file

In fairness, XML files are normally not meant for viewing directly, but if you do, use the default program designated for opening XML files (which is normally Internet Explorer, although any browser will do). Doing so will present the XML in an easy to read format - with line breaks.

To read the XML back to a HashTable, you can use this function....
    Public Function XMLtoHashTable(ByVal xmlStr As String) As Hashtable
        Dim hash As New Hashtable
        Dim sr As New IO.StringReader(xmlStr)
        Dim ds As New DataSet
        For Each dr As DataRow In ds.Tables("Item").Rows
            hash.Add(dr("Key"), dr("Value"))
        Return hash
    End Function

Open in new window


Author Comment

ID: 24155560
Thank you webtubbs.

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In my previous article ( we saw the basics of serialization and how types/objects can be serialized to Binary format. In this blog we wi…
Real-time is more about the business, not the technology. In day-to-day life, to make real-time decisions like buying or investing, business needs the latest information(e.g. Gold Rate/Stock Rate). Unlike traditional days, you need not wait for a fe…
In this video, viewers are given an introduction to using the Windows 10 Snipping Tool, how to quickly locate it when it's needed and also how make it always available with a single click of a mouse button, by pinning it to the Desktop Task Bar. Int…
If you’ve ever visited a web page and noticed a cool font that you really liked the look of, but couldn’t figure out which font it was so that you could use it for your own work, then this video is for you! In this Micro Tutorial, you'll learn yo…

688 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question