Question

I am using .NET 4.0 and I would like to use the app.config file to store same parameter settings. I do the following. I use the Settings tab in the project properties to create my parameters.

This add the information in the app.config file like this:

<MyApp.Properties.Settings>
      <setting name="param1" serializeAs="String">
        <value>True</value>
      </setting>
<MyApp.Properties.Settings>

In my view model (in my code) I can access to the information in this way:

bool myBool = MyApp.Properties.Default.param1;

When I try to change the value in the config file, I try this:

Properties.Settings.Default.param1 = false;

But this causes an error, that param1 is read-only.

So how can I update my config file from my code?

Answer 1

Well, I read the link of Hari Gillala, in which one user suggested to edit directly the app.config file, that is a xml file.

So in project properties–>settings I create the parameters that I need. Then, to load a parameter in code I do the following:

_myViewModelProperty = MyApp.Properties.Settings.Default.MyParam1;

In this way, I can read easily the information of the config parameter. Is typed, so in disign time I can see if the asign is correct or not.

To update de config file, I edit the app.config file with the xml libraries of .NET.

    System.Xml.XmlDocument xml = new System.Xml.XmlDocument();
    xml.Load(AppDomain.CurrentDomain.SetupInformation.ConfigurationFile);
    System.Xml.XmlNode node;
    node = xml.SelectSingleNode("configuration/applicationSettings/MyApp.Properties.Settings/setting[@name='myparam1']");
    node.ChildNodes[0].InnerText = myNewValue;
    xml.Save(AppDomain.CurrentDomain.SetupInformation.ConfigurationFile);

In this way, I create a xml document (xml variable) and load the information of the app.config file. Then, I search for the node that I want to update, update its information (InnerText property) and finally I save the changes.

In this way, I can update the app.config. It is what I want, because in a portable application, only one user will use it, and I want that the configuration is applied in any computer in which I run the application.