How You Can Change the applicationSettings and userSettings Section of config File at Runtime.

• Download source - 33.9 KB

Disclaimer

I am not in any way involved in the administration of The Code Project, and the administrators have not, in any capacity, asked me to write this article. This article is completely based on my own personal views and experiences in programming and technical writing.  

Introduction

I searched on Google and did not find any exact results of resolving my problem “How can we change the applicationsettings values from a different project?” Finally I found something but there weren't many details available, so by adding some code I got how it can be done. This article shows how you can change the applicationsettings and usersettings section of config file at runtime. You can use it to create a project like Configuration Manager to manage multiple config files. You can also find an exciting resource on editing the appsetting key/value section at Edit and Encrypt Web.Config Sections Using C# 2.0.

Background

As per the MSDN - Application settings allow you to store and retrieve property settings and other information for your application dynamically, and they allow you to maintain custom application and user preferences on the client computer. You might want to store a user's color preferences, and then retrieve them the next time the application runs. Application settings can be stored as any data type that is XML serializable or has a TypeConverter that implements ToString/FromString. The most common types are String, Integer, and Boolean, but you can also store values as Color, Object, or as a connection string. In Visual Basic projects, you can access application settings at run time using the My.Settings object. But I want to modify these settings by another project, so I have to write some custom code for accomplishing my task.

How the Application Runs

1. When you run the source project, you get the following screen:

   

2. Click the Load button, which loads the below settings in DataGridView:

   

3. After changing the setting values:

   

4. Click the Update button to update the changed values to config file.

Using the Code 

1. Create a Web config file and add the following settings using the Solution->Property->Settings.

See the app.config file now. The application settings are added.

2. Create a class named ConfigSettings as below:

   Public Class ConfigSettings
       Private _settingName As String
       Private _settingValue As String
       Private _serializeAs As String
   
       Public Property SettingName() As String
           Get
               Return _settingName
           End Get
           Set(ByVal value As String)
               _settingName = value
           End Set
       End Property
   
       Public Property SettingValue() As String
           Get
               Return _settingValue
           End Get
           Set(ByVal value As String)
               _settingValue = value
           End Set
       End Property
   
       Public Property SerializeAs() As String
           Get
               Return _serializeAs
           End Get
           Set(ByVal value As String)
               _serializeAs = value
           End Set
       End Property
   
   End Class

3. Open the form and add the following controls:
   1. DataGridView and name it dgvAppSetting 
   2. Load File button and name it btnLoadFile 
   3. Update button and name it btnUpdate

   See the following image:

   

4. Add the following global variables:

    Private m_strSettingName As String
    Private ConfigSettingsList As New List(Of ConfigSettings)

5. Write the code shown below in the click event of btnLoadFile button:

        Private Sub btnLoadFile_Click(ByVal sender As System.Object, _
   		ByVal e As System.EventArgs) Handles btnLoadFile.Click
           Try
               Dim strFile As String
               Dim ConfigDoc As New XmlDocument()
               'Store the name of the file
               strFile = String.Format("{0}/_
   		ReadConfigurationAppSettingSection.exe.config", _
   		Directory.GetCurrentDirectory.ToString())
               'Load the configuration file as XML document
               ConfigDoc.Load(strFile)
               'Assign  the [applicationSettings] node 
               Dim applicationSettingsNode As XmlNode = _
   		ConfigDoc.GetElementsByTagName("applicationSettings")(0)
   
               'For reading the user settings use below
               'Dim applicationSettingsNode As XmlNode = _
   		ConfigDoc.GetElementsByTagName("userSettings")(0)
   
               ConfigSettingsList.Clear()
   
               'Run for each child node and create the ConfigSettingsList 
               'collection of [applicationSettings] child nodes
               For Each objXmlNode As XmlNode _
   		In applicationSettingsNode.FirstChild.ChildNodes
                   Dim objConfigSettings As New ConfigSettings
                   With objConfigSettings
                       .SettingName = objXmlNode.Attributes(0).Value
                       .SerializeAs = objXmlNode.Attributes(1).Value
                       .SettingValue = objXmlNode.FirstChild.InnerText
                   End With
                   ConfigSettingsList.Add(objConfigSettings)
               Next
   
               'Assign the collection to Datasource
               ConfigSettingsBindingSource.DataSource = ConfigSettingsList
           Catch ex As Exception
               MessageBox.Show(ex.Message, Me.Text, MessageBoxButtons.OK, _
   			MessageBoxIcon.Error)
           End Try
       End Sub
   End Class

6. Write a method which is used as predicate for finding the setting in collection:

       Private Function GetSetting(ByVal objConfigSettings As ConfigSettings) _
   	As Boolean
           Return m_strSettingName = objConfigSettings.SettingName
       End Function

7. Write the below code in the click event of btnUpdate button:

    Private Sub btnUpdate_Click(ByVal sender As System.Object, _
   	ByVal e As System.EventArgs) Handles btnUpdate.Click
           Try
               Dim strFile As String
               Dim ConfigDoc As New XmlDocument()
               strFile = String.Format("{0}/_
   		ReadConfigurationAppSettingSection.exe.config", _
   		Directory.GetCurrentDirectory.ToString())
               ConfigDoc.Load(strFile)
               Dim applicationSettingsNode As XmlNode = _
   		ConfigDoc.GetElementsByTagName("applicationSettings")(0)
   
               'For reading the user settings use below
               'Dim applicationSettingsNode As XmlNode = _
   		ConfigDoc.GetElementsByTagName("userSettings")(0)
   
               For Each objXmlNode As XmlNode _
   		In applicationSettingsNode.FirstChild.ChildNodes
   
                   m_strSettingName = objXmlNode.Attributes(0).Value
   
                   Dim objConfigSettings As ConfigSettings = _
   			ConfigSettingsList.Find(AddressOf GetSetting)
   
                   If objConfigSettings IsNot Nothing Then
                       With objConfigSettings
                           objXmlNode.Attributes(0).Value = .SettingName
                           objXmlNode.Attributes(1).Value = .SerializeAs
                           objXmlNode.FirstChild.InnerText = .SettingValue
                       End With
                   End If
               Next
               ConfigDoc.Save(strFile)
               MessageBox.Show("Updated Successfully.", Me.Text, _
   		MessageBoxButtons.OK, MessageBoxIcon.Information)
           Catch ex As Exception
               MessageBox.Show(ex.Message, Me.Text, _
   		MessageBoxButtons.OK, MessageBoxIcon.Error)
           End Try
   
       End Sub

History

• 25^th March, 2009: Initial post

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)