Writing to the app.config file

[Edneeis]

Is there an internal way to write or set values in the app.config file? Everything seems to be read only. Or is it better to have a seperate file for read/write values? I figured I'd save my resize info in there but then thought twice when there isn't a default way to save values only read them. I could open it as a dataset or xml document I guess. What is everyone else doing?

[DevGrp]

Use serialization to write a binary or an XML file with all your settings that you want to persist.

[Edneeis]

I just rolled my own AppSettingsWriter class.

Public Class AppSettingsWriter
 
    Public Sub SetValue(ByVal key As String, ByVal value As Object)
        Dim ds As New DataSet()
        ds.ReadXml(GetConfigFilename)
        Dim dr() As DataRow = ds.Tables("add").Select(String.Concat("key='", key, "'"))
        dr(0).Item("value") = value
        ds.WriteXml(GetConfigFilename)
        ds.Clear()
    End Sub
 
    Private Function GetConfigFilename() As String
        Return String.Concat(Path.GetFileName(Application.ExecutablePath), ".config")
    End Function
 
End Class
 
'syntax
        Dim aw As New AppSettingsWriter()
        aw.SetValue("WindowState", CType(Me.WindowState, Integer))
        aw.SetValue("height", Me.Height)
        aw.SetValue("Width", Me.Width)

[Musician]

The world loves datasets - it's official. I would recommend using the XmlWriter for fast efficient writing and updating of keys in your app.config.

[Edneeis]

Well I tried your suggestion with the XMLTextWriter but that was more trouble than its worth because it tries to write the whole file not just the parts I want to change. Unless you have an example for me?

[Edneeis]

Here is the code I used:

Dim xw As New XmlTextWriter(GetConfigFilename, Encoding.UTF8)
        xw.WriteStartDocument()
        xw.Indentation = 5
        xw.WriteStartElement("configuration")
        xw.WriteStartElement("appSettings")
        xw.WriteStartElement("add")
        xw.WriteAttributeString("key", key)
        xw.WriteAttributeString("value", value)
        xw.WriteEndElement()
        xw.WriteEndElement()
        xw.WriteEndElement()
        xw.WriteEndDocument()
        xw.Close()

I hadn't used the XMlTextWriter before so be gentle

[Slow_Learner]

The docs for XMLWriter/et al. make my brain hurt bad. I want to start playing with XML because I can see a lot of applications for it in my current project but the docs are a bit intimidating for me :/

[Edneeis]

I hear ya I've only tested the water really. I never used it before .NET really and so far I mainly only work with it through a dataset.

[Musician]

I have an example at work which I will post tomorrow when I go into the office
The method as I recall involves creating a node which is an xpath selection of the node you are looking for. Then changing it and saving the details.
I've read a couple of books on XML and it still makes my brain hurt too. I always get the impression when reading about it that the guy writing the article/book thinks xml is simple and sees no need to explain it as simply as possible.