<connectionStrings>
<addname="AppConfigChange.My.MySettings.Connstr"
connectionString=
"Data Source=wghosh2k3"sqlexpress;Initial Catalog=Northwind;Integrated Security=True"
providerName="System.Data.SqlClient" />
Dim sNewConnStr As String = ""
'Get the file info
Dim config As System.Configuration.Configuration = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None)
'Load the file info
Dim xml = XElement.Load(config.FilePath)
'Get the first config section (first connection string info)
Dim connStrXML = xml.Descendants("connectionStrings").Elements().First()
'Get the connection string value
Dim connStr = connStrXML.Attribute("connectionString").Value
'Create an array with ';'
Dim arrConn() As String = connStr.Split(";")
For i As Int16 = 0 To arrConn.Length - 1
'Get the attribute and value splitted by "="
Dim arrSubConn() As String = arrConn(i).Split("=")
If (arrSubConn.Length = 2) Then
Dim sConnAttr As String = ""
Dim sConnValue As String = ""
sConnAttr = arrSubConn(0)
sConnValue = arrSubConn(1)
'Change Database name
If (sConnAttr = "Initial Catalog") Then
'This is the place where you will be changing the database name
sConnValue = "NewDBName"
End If
'Generate newly altered connection string
sNewConnStr += sConnAttr + "=" + sConnValue + ";"
End If
Next
After doing everything you need to save it back to the same file,
'Modify the existing connection string information
connStrXML.SetAttributeValue("connectionString", sNewConnStr)
'Saving config at the same place
xml.Save(config.FilePath)
