Set a value in a Configuration File in a Windows Forms C# Application

Question

Using Microsoft Visual Studio Community 2019.

How can I set a value (a path) in a Configuration File, so it can be updated and then restart the application with the updated value (without having to recompile the application)?

This is a legacy project that I don't really know. The most important requirement is to have the capability to change this path without having to recompile the application. This is what I've tried so far:

Preliminary step:

To check what kind of project it is. Based on this question, I check that the .csproj file contains:

<OutputType>WinExe</OutputType>

So, to my understanding the project is a WinForms Application.

Also, I've tried to seach for the GUID found in the .csproj file:

<ProjectGuid>{B1DD5159-A8E8-4DBE-964F-DB9679F60192}</ProjectGuid>

But the seach for that GUID gives no result, and also is not listed on this two GUID list:

• List 1
• List 2

Note: The core of the question is based the asumption that this project is a WinForms Application. Please let me know if this the wrong way of finding the type of this project, or even better pointing out the right way of doing it.

---

First step:

To edit the Configuration File, going to the Solution Explorer, in which I cannot find any .config file, but if I check the files of this project (via Windows Explorer), I found a app.config file.

I update this file outside of Visual Studio (I'll come back to this later), and add a test property. This modification is done following the structure found in the file, no external source to do this modification.

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <configSections>
        <sectionGroup name="userSettings" type="System.Configuration.UserSettingsGroup, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" >
            <section name="LF10Demo.Properties.Settings" type="System.Configuration.ClientSettingsSection, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" allowExeDefinition="MachineToLocalUser" requirePermission="false" />
        </sectionGroup>
    </configSections>
    <userSettings>
        <LF10Demo.Properties.Settings>
            <setting name="AutoStepping" serializeAs="String">
                <value>True</value>
            </setting>
            ...
            <setting name="test" serializeAs="String">
                <value>C:\Temp</value>
            </setting>
        </LF10Demo.Properties.Settings>
    </userSettings>
</configuration>

Then, in the code try to get the value:

var appSettings = System.Configuration.ConfigurationManager.AppSettings;
string value1 = System.Configuration.ConfigurationManager.AppSettings["test"];
string value4 = System.Configuration.ConfigurationSettings.AppSettings.Get("test");

None of which bring the value stored in the app.config file, in fact all of then brings null.

Then, update the app.config file following this post configuration file in a Windows Forms C# Application

<?xml version="1.0" encoding="utf-8" ?>
    <configuration>
      <appSettings>
        <add key="test" value="C:\Temp" />
      </appSettings>
    </configuration>

Which didn't work either.

Second step

Going back to the modification of the app.config, discart this modifications and add a different Configuration File (after all, the app.config is not visible in the Solution Explorer). This consist in adding a new configuration file app1.config following this post related with configuration file in a Windows Forms C# Application and also this one Adding and reading from a Config file.

So after adding the new configuration file, all my apptemps with System.Configuration.ConfigurationManager.AppSettings brings null.

Also, when adding the this new configuration file, if I choose app.config the show me a message saying

A file with the name 'App.config' already exits...

So after all, the project is (in some way) finding that file.

Other related information:

In the file Settings.Designer.cs if I add the following:

[global::System.Configuration.UserScopedSettingAttribute()]
[global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
[global::System.Configuration.DefaultSettingValueAttribute("C:\\Temp")]
public string test
{
    get {
        return ((string)(this["test"]));
    }
    set {
        this["test"] = value;
    }
}

And then using this line:

string value8 = Properties.Settings.Default.test;

Is possible to get the value, but this does not satisfy the requirement that the path can be changed without recompiling the application.

Other related links:

This are other links related with adding a configuration file to Visual Studios projects, I've also tried some of this solutions but without obtaining the expected results:

• App.Config file in console application C#
• Adding and reading from a Config file
• Retrieving Value from Config file in C# Application Doesn't Work

Answer 1

Look in your bin directory and you should see a file named YourProjectName.exe.config with a type of XML configuration. Whatever is in your app.config is copied here when you compile the project. You can change the values in code as follows:

static void UpdateAppSettings(string key, string value)
        {
            var configFile = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
            var settings = configFile.AppSettings.Settings;
            settings[key].Value = value;
        }