Develop Reference

C# - Unable to write to app.config after deployment

I am developing a WPF application which runs well in visual studio v.2022 very well. My problem is when I deploy the application to another computer for testing it does not seem to be updating app.config data. When I change the ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None) to NONE it works well in both debug and release mode in Visual Studio but throws an error when deployed to another computer. The error I am getting is "System configuration.configuration error exception - An error ocurred while loading the the configuration file myApp.dll.config. Access denied "
I gather that the user has no write privileges on the Program Files folder where the app.config is stored. However, when I change the user level to either Roaming or Roaming and local, then nothing happens as the configuration file is not located and if at all the changes are made then they are not persisting. Here is my app.config file
<configuration>
<appSettings>
<add key="Server" value=""/>
<add key="Port" value=""/>
<add key="Database" value=""/>
<add key="User" value=""/>
<add key="Pwd" value=""/>
<add key="Code" value=""/>
<add key="Access" value=""/>
<add key="Status" value=""/>
<add key="EndDate" value=""/>
</appSettings>
</configuration>
Here is my method for updating the the app.config
public static void UpdateSetting(string key, string value)
{
Configuration roaming = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
ExeConfigurationFileMap fileMap = new ExeConfigurationFileMap();
fileMap.ExeConfigFilename = roaming.FilePath;
Configuration configuration = ConfigurationManager.OpenMappedExeConfiguration(fileMap, ConfigurationUserLevel.None);
var appSettings = configuration.AppSettings;
foreach (var keys in appSettings.Settings.AllKeys.Where(x => x.StartsWith(key)))
{
appSettings.Settings[keys].Value = value;
}
configuration.Save(ConfigurationSaveMode.Modified);
ConfigurationManager.RefreshSection("appSettings");
}
and here is an example of how the method is called Settings.UpdateSetting("Code", _Code);
Any help will be much appreciated

Following #Joe's comment it occurred to me that it was not possible to write to config application data at runtime. I opted to create a new section in the config file in the Properties.Settings folder in my solution and assigned the scope to User and not application since the user is able to update the data at runtime. Double click on the settings.Settings file to open in designer view and literally entered the settings names to be stored.
The stored settings can be saved and retrieved using the methods below.Properties.Settings.Default.yourSetting. to get the settings.
And to store/save the settings
Properties.Settings.Default.yourSetting= val;`
Properties.Settings.Default.Save();`
That solved my problem.

Read separate web.config file outside the application folder

I need to read web.config file, outside the application's folder (located in any other directory).
I tried this code:
string filePath = #"C:\Users\Idrees\Downloads\New folder\Web.config";
Configuration c1 = ConfigurationManager.OpenExeConfiguration(filePath);
var value1 = c1.AppSettings.Settings["Key1"].Value;
But it is giving me the error:
Object reference not set to an instance of an object.
Because here, c1.AppSettings is an object, but c1.AppSettings.Settings contains not items (hence 0 Count). It is not really loading the AppSettings keys. When trying to read any Key from Settings collection, it gives this error.
Is there any way how to load AppSettings keys from a web.config file outside the application folder.
If I put same file within application folder, then it reads the keys successfully.
This is my sample config file's content:
<?xml version="1.0" encoding="utf-8"?>
<!--
For more information on how to configure your ASP.NET application, please visit
http://go.microsoft.com/fwlink/?LinkId=169433
-->
<configuration>
<connectionStrings>
<!--here goes my connection strings-->
</connectionStrings>
<appSettings>
<add key="Key1" value="Value1" />
<add key="Key2" value="Value2" />
<add key="Key3" value="Value3" />
</appSettings>
</configuration>
I have a web application already running on my server. And I need to develop a small utility which has to do some job in database, and I don't want to write db credentials or connection string(and some other additional app-settings) in each application, I want it to read same thing from web.config.

You can using ConfigurationManager to read arbitrary configuration files by opening a mapped exe configuration as follows:
var filePath = #"C:\Users\Idrees\Downloads\New folder\Web.config";
var fileMap = new ExeConfigurationFileMap { ExeConfigFilename = filePath };
var configuration = ConfigurationManager.OpenMappedExeConfiguration(fileMap, ConfigurationUserLevel.None);
var value = configuration.AppSettings.Settings["Key1"].Value;

As I understand from your comment you want some kind of shared configuration accross multiple app on the same computer. You may consider using external file like this :
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
</startup>
<connectionStrings configSource="config\connString01.config"/>
<appSettings file="config\config01.config">
<add key="Var3" value="Var3 value from main config file"/>
</appSettings>
in above .config example connectionStrings is sourced from an other file. Below an example what can be such an external config file:
<connectionStrings>
<add name="SQLConnectionString01" connectionString="Data Source=sourcename01;Initial Catalog=cat01;Persist Security Info=True;Integrated Security=true;"/>
</connectionStrings>

Read documentation: ConfigurationManager.OpenExeConfiguration on MSDN
public static Configuration OpenExeConfiguration(
string exePath
)
This is EXE path

C#: modify web.config at runtime

I have an entry in my <appSettings> section which contains my connection string. By default, it looks for the file on the root of the C: drive.
<appSettings>
<add key="EnvironmentFile" value="C:\environment.extension" />
</appSettings>
I need to modify the value of the entry programmatically since the app will be deployed to a different server (Appharbor), which I don't have access to the C drive. I moved the environment file to the root of the app directory which means I need to modify the appSettings value for EnvironmentFile. Here's what I have tried so far, I have resorted to the following since I can't put relative values on web.config such as
value="~/environment.extension"
Default.aspx:
protected void Page_Load(object sender, EventArgs e)
{
if(ConfigurationManager.AppSettings["EnvironmentFile"] == null)
{
Configuration config = WebConfigurationManager.OpenWebConfiguration("~");
config.AppSettings.Settings.Add("EnvironmentFile", AppDomain.CurrentDomain.BaseDirectory + #"environment.extension");
config.Save(ConfigurationSaveMode.Minimal);
ConfigurationManager.RefreshSection("appSettings");
}
if (IsPostBack == false)
{
//--some business logic here that gets data from the database
}
}
In debug mode, it does modify my web.config but throws an exception since it is already executing the code on my if block. Are there other ways to do this such that I have different configuration for debug and release?

Yes, there is another way of doing this.
If you right click on your Web.Config in Visual Studio you'll see an option to 'Add Config Transform'. This allows you to create transformations for your various configurations. The newly added Web.XXX.config files will have some examples of how to transform your entries, but a simple example would be:
In your base Web.Config:
<appSettings>
<add key="Mode" value="Development" />
</appSettings>
And then in a WebConfig.LiveRelease.config file you might have this:
<appSettings>
<add key="Mode" value="Live" xdt:Transform="SetAttributes" xdt:Locator="Match(key)"/>
</appSettings>

Can't get app.config value "connectionStrings"?

I am writing a program in visual studio,now i can't get the value of app.config.My app.config look like this:
<?xml version="1.0"?>
<configuration>
<connectionStrings>
<add name="connStr" connectionString="Data Source=Dolphin-PC;Initial Catalog=jsptpd_SYS;Persist Security Info=True;User ID=sa;Password=ccir"/>
</connectionStrings>
</configuration>
And the code i am try to get the value:
try
{
con2 = System.Configuration.ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;
logger.Info("try to get connectionstr success:" + connStr);
}
catch(Exception ex)
{
logger.Info("try to get connectionstr failed:" + ex.ToString());
}
The log's output:
2013-12-14 16:22:28,710 [1] INFO ApplicationInfoLog [(null)] <(null)>
- try to get connectionstr failed:System.NullReferenceException:
object reference not set to instance.
on Jsptpd.JobScheduler.jsptpdJobScheduler..ctor()
location D:\jsptpd\Code\jsptpdJobScheduler\jsptpdJobScheduler\jsptpdJobShedule.cs:line 46
Where is wrong? Why can't read the ConnectionStrings?

Your section is declared as NameValueSectionHandler. As this article points out, this handler returns a NameValueCollection, not the IDictionary that you cast it to afterwards. That's why as IDictionary results in a null value.
Either declare your section as DictionarySectionHandler or change IDictionary to NameValueCollection.

If that config you posted is really what you have, then that config is just plain wrong.... you have two nested <configuration> sections - that won't ever work!
If your config really looks like what you posted, you need to change it to look like this:
<?xml version="1.0"?>
<configuration> <!-- one and ONLY one <configuration> node! -->
<configSections> <!-- directly under <configuration> -->
<section name="quartz" type="System.Configuration.NameValueSectionHandler, System, Version=1.0.5000.0,Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
<configSections>
<connectionStrings> <!-- directly under <configuration> -->
<add name="connStr" connectionString="Data Source=Dolphin-PC;Initial Catalog=jsptpd_SYS;Persist Security Info=True;User ID=sa;Password=ccir"/>
</connectionStrings>
<quartz> <!-- directly under <configuration> -->
...........
</quartz>
<appSettings> <!-- directly under <configuration> -->
<add key="connStr" value="Data Source=Dolphin-PC;Initial Catalog=jsptpd_SYS;Persist Security Info=True;User ID=sa;Password=ccir"/>
</appSettings>
</configuration>
There should be only one <configuration> section, and all other tags, like <configSections>, <quartz>, <connectionStrings> and <appSettings> should be directly inside the one and only <configuration> element

Check your app.config file attribute set,make sure that Generate Operation is not embeded resource.
Because you read the app.config through ConfiguationManager class,the Configuration read file like this:
http://msdn.microsoft.com/en-us/library/system.configuration.configurationmanager.aspx
•Read and write configuration files as a whole. Your application can read and write configuration settings at any level, for itself or for other applications or computers, locally or remotely. Use one of the methods provided by the ConfigurationManager class to open a configuration file such as SampleApp.exe.config. These methods return a Configuration object that in turn exposes methods and properties you can use to work with the associated configuration files. The methods perform read or write operations and create the configuration data every time that a file is written.
If you set embeded resource,the bin directionary could not generate the SampleApp.exe.config file,so the ConfigurationManager could read your config file.
So if you want to correct the problem,do this
choose the app.config file in resource manager of visual studio:
set the copy to outout dirctionary to:
No copy
set the generte operation to:
None
The problem will fixed.

NullReferenceException when trying to write in app.config

I use app.config to store some info. My file looks like this:
<?xml version="1.0"?>
<configuration>
<appSettings>
<add key="używajDomyślnie" value="false" />
<add key="sInicjały" value="ŁM" />
<add key="nPrzedstawiciel" value="Łukasz Motyczka" />
<add key="nPozycja" value="Przedstawiciel Naukowo-Handlowy" />
<add key="nTelefon" value="+48 784 567 670" />
<add key="nEmail" value="motyczka.lukasz#bmgrp.pl" />
<add key="dataoferty" value="" />
<add key="ostatniNrOferty" value="" />
</appSettings>
<connectionStrings>
<add name="Oferty_BMGRP.Properties.Settings.BazaDanychConnectionString" connectionString="Data Source=|DataDirectory|\BazaDanych.sdf" providerName="Microsoft.SqlServerCe.Client.3.5" />
</connectionStrings>
<system.windows.forms jitDebugging = "true"/>
</configuration>
The snippet that throws a NullexceptionError is:
if(checkBox1.CheckState == CheckState.Checked)
{
Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
AppSettingsSection app = config.AppSettings;
//app.Settings.Clear();
//app.Settings.Add("używajDomyślnie", "true");
//app.Settings.Add("sInicjały", sInicjaly.ToString());
//app.Settings.Add("nPrzedstawiciel", nPrzedstawiciel.ToString());
//app.Settings.Add("nPozycja", nPozycja.ToString());
//app.Settings.Add("nTelefon", nTelefon.ToString());
//app.Settings.Add("nEmail", nEmail.ToString());
config.AppSettings.Settings["używajDomyślnie"].Value = "true"; //<- THIS LINE GIVES ME AN ERROR
config.AppSettings.Settings["sInicjały"].Value = sInicjaly.ToString();
config.AppSettings.Settings["nPrzedstawiciel"].Value = nPrzedstawiciel.ToString();
config.AppSettings.Settings["nPozycja"].Value = nPozycja.ToString();
config.AppSettings.Settings["nTelefon"].Value = nTelefon.ToString();
config.AppSettings.Settings["nEmail"].Value = nEmail.ToString();
config.Save(ConfigurationSaveMode.Modified);
form1.checkBox1.CheckState = CheckState.Checked;
}
When I debug it or build release in VS it works fine. Also it works on my laptop. But on every other machine I have null exception error. Also it worked until I tried to make a setup project (which works but meesed up this one). Whatmore the jit Debugging does not work, I still have a .net error (continue or exit).
Also I did notice that on my computer and some other laptop I was using, when error occurs it shows:
System.NullReferenceException: Odwołanie do obiektu nie zostało ustawione na wystąpienie obiektu.
w Oferty_BMGRP.Form3.button1_Click(Object sender, EventArgs e) w C:\Users\user\Documents\Visual Studio 2010\Projects\BMGRP\Oferty BMGRP\OfertyBMGRP\Form3.cs:wiersz 282
Sorry for polish, but what I want to point is that on both machines it shows path to same folder, which exists only on one of them.
Please help :)
EDIT!
I just found out that if I build the release. Run application and make th above code run, it creates MyApplication.exe.config file, and then app works fine on every computer. How can I make it to work as setup project, where .exe.config is not created, only app.config?

You're trying to set the Value property of a null object. Settings["blah"] is returning null before you even have a chance to set the value.
Try this instead:
config.AppSettings.Add("key", "value");
Or maybe will a null check:
if(config.AppSettings.Settings["key"] == null)
{
config.AppSettings.Add("key", "value");
}

MyApplication.exe.config is app.config, and you shouldn't mess with that paradigm. It's how .net applications are intended to work.
If you want to do your configuration differently than that, than you can either do your own file IO or find another external configuration library.