VB Application Settings

VB Application Settings

• Alan Cobb

  I have allready achieved this in VS 2005 and VS 2003.
  I have written a function that replaces a certain value in the XML configuration file by reading teh stream of the original file, replacing it by the new value, and saving that stream with the exact same filename of the configuration file.
  
  I'm using this to alter my database connection at runtime, and do not seem to have unpleasant side-effects. BUT this requires a restart of the application!!
  
  My connectionstring in the  XML:(i gave the important keys a colour so you can see where i search for them in the code)
  
  <connectionStrings>

  <add name="SphinxTrace.Settings.pvsConn" connectionString="Driver={Pervasive ODBC Client Interface};ServerName=SPHINX-KDME;dbq=C:\Belgosuc" />

  <add name="SphinxTrace.Settings.sqlConn" connectionString="Data Source=.;Initial Catalog=SQLDeClercq;Integrated Security=True"

  providerName="System.Data.SqlClient" />

  </connectionStrings>

  The code that works for the above xml snippet:
  
  Public Sub ReplaceConfigSettings(ByVal FName As String, ByVal key As String, ByVal val As String)

  Dim xDoc As New Xml.XmlDocument

  Dim xNode As Xml.XmlNode

  On Error GoTo ErrorHandler

  xDoc.Load(Application.StartupPath & "\" & FName)

  For Each xNode In xDoc("configuration")("connectionStrings")

  If (xNode.Name = "add") Then

  If (xNode.Attributes.GetNamedItem("name").Value = key) Then

  xNode.Attributes.GetNamedItem("connectionString").Value = val

  Exit For

  End If

  End If

  Next
  
  'save the altered stream as a file with the exact name of current config file
  xDoc.Save(Application.StartupPath & "\" & FName)

  ExitHandler:

  xDoc = Nothing

  Exit Sub

  ErrorHandler:

  MsgBox("Check configuration replace method", MsgBoxStyle.Information)

  Resume ExitHandler

  End Sub

  
  
  ------------------------------------------------------------------------
  
  I hope this works for you, it doesn't gave me any problems!
  
  Truly yours,
  
  Kenny De Maertelaere
  Junior .NET developer
  
  
  

  
  

• tirthankar

  haleyweb2005 wrote:

  Im trying to build a program that runs on a database.  I have tryed everything i can think of to change my connection string at runtime.  What i want to do is enable a user to select a local SQL server that containes a copy of my database, and save it to the application settings.  i keep getting a read only message when i try to change the app settings connectionstring setting.  im not sure if i worded that right, if you need more information, please let me know. Thank you, Andrew

  
  
  We've solved a similar issue with the use of a Data Acces Object (DAO).
  
  What this does is creates an object similar to the following...
  
  

  DAO

  string DatabaseName string ServerName

  public ExecuteNonQuery(StoredProcedureName, ParameterList) as Boolean public GetDataFromStoredProcedure(StoredProcedureName, ParameterList, DataSet) as Boolean private _getConnection(SqlConnection) as Boolean private _getCommand(SqlCommand) as Boolean private _getData(DataSet, Parameters, SPName) as Boolean private _executeNonQuery(SPName,Parameters) as Boolean

  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  Ok - so we build the CS on the fly, using the supplied parameters which can be obtained from the calling application.
  
  e.g.
  
  MyDAO.ServerName = "SQL50"
  MyDAO.DatabaseName = "MyDatabase"
  
  In the calling application we have a custom XML file that can be read/written with the database server name such as  "SQL50\SQL001" and database name such as "MyApplicationDatabase" in an entry something like this...
  
  <CustomApplicationSettings>
     <ApplicationSetting>
           <key>ServerName</key>
           <value>SQL50\SQL001</value>
     </ApplicationSetting>
     <ApplicationSetting>
           <key>DatabaseName</key>
           <value>MyApplicationDatabase</value>
     </ApplicationSetting>
  </ CustomApplicationSettings>
  
  And read the value from the XML node for each setting into the DAO. This means you can read/write as you wish. Your not leaving any particularly sensitive info open, since the passwords, usernames etc. shouldn't be in here. We use a pass through of the identity to authenticate which works for us.
  

• Xeon_boy

  There are two types of application settings, based on scope:

  • Application-scoped settings can be used for information such as a URL for a Web service or a database connection string. These values are associated with the application, so users cannot change them at run time.

  • User-scoped settings can be used for information such as remembering the last position of a form or a font preference. Users can change these values at run time.

  You can change the type of a setting using the Scope property.

  See details in http://msdn2.microsoft.com/en-us/library/a65txexh.aspx
  
  Note that the ConnectionStringSetting is ApplicationScoped setting and so you can never change it at run time.
  
  Hope this help.
  

• thinkCode96

  ok, so if i wanted to change where the database location is at runtime, how would i go about that   all i need to do is change the server name, and i will be good to go, but i just cant figure it out.  Im trying to add a options form so that a user can select which server they want to get the database from.  this program will be used at another location, and i dont know what ther server name is.  all i will be doing is giving them a empty, premaid database to put on there server.  if i were running the program on the same computer that the server was on, i wouldnt have a problem, but unfortunatly, im not.
  
  Thank you,
  Andrew
  

• Andgermany

  I found a link on the forums:
  https://blogs.msdn.com/smartclientdata/archive/2005/07/25/443034.aspx

  Basically I had a situation where I wanted to change the connectionstring that M$ store when using the funky project data sources way of coding.

  All I did is added this sub to the settings.vb file (instructions how to view the setting code in included in that link above)

  Private Sub MySettings_SettingsLoaded(ByVal sender As Object, ByVal e As System.Configuration.SettingsLoadedEventArgs) Handles Me.SettingsLoaded

  Me.Item("cnDatabase") = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Me.Item("UserSettingDatabaseLocation")

  End Sub
  
  Where cnDatabase is the name of the Connection you have used for your datasets, and UserSettingDatabaselocation was just a User setting that i have used, but you could set that to anything like your own XML based setting or anything.

  Good Luck!

  
  
  

• JanJacobs

  Well, I do not see a easy way to change the conenction string value at run time with the current type dataset generated code.
  
  You can surely modify the generated dataset code (xxxdataset.designer.xsd) to suit your need.  
  
  The initConeection function can be modified to take your own connection string.
  

  Private Sub InitConnection()

     Me._connection = New System.Data.SqlClient.SqlConnection

     Me._connection.ConnectionString = Global.WindowsApplication6.My.MySettings.Default.NorthwindConnectionString

  End Sub
  
  

  However, I do not recommend to do so as the file will be regenerated if there is a change in the dataset. Use carefully and on your own risk.
  
  HTH.
  
• VB Application Settings