Updating a value in a local app.config

Question

I've got an exe that reads some values from its local app.config file:

TargetDate = ConfigurationManager.AppSettings.Get("ThresholdDate");

// and try to update with the current date
ConfigurationManager.AppSettings.Set("ThresholdDate", "2011-09-01");

I thought it worked once, but am not seeing the app.config getting updated at all now.

is this helpful: http://stackoverflow.com/questions/980440/update-app-config-system-net-setting-at-runtime — Baz1nga, Sep 01 '11 at 17:43

Baz1nga · Answer 1 · 2011-09-01T18:40:30.697

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I think you can try something like this:

var config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None)
//change the config value
config.Save(ConfigurationSaveMode.Modified);
ConfigurationManager.RefreshSection("appSettings");

I am not sure abt the syntax for changing the config value but I have done an Add before and I know you can do a remove so I guess you could do a combination of remove and add like this:

config.AppSettings.Settings.Remove("ThresholdDate");
config.AppSettings.Settings.Add("ThresholdDate", "2011-09-01");

edited Sep 01 '11 at 18:40

answered Sep 01 '11 at 17:47

Baz1nga

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what is the C# syntax for changing the config value? – user360943 Sep 01 '11 at 18:00
did you do a save and refresh after that? – Baz1nga Sep 01 '11 at 19:15
config.Save(ConfigurationSaveMode.Modified); ConfigurationManager.RefreshSection("appSettings"); – user360943 Sep 01 '11 at 19:24
I can save the value,and turn right around and extract the value right away, but it does not persist after application ends execution – user360943 Sep 01 '11 at 21:16
looks like it is being changed in the .vshost.exe.config instead of app.config and the value is not persisted after execution – user360943 Sep 01 '11 at 21:36
So am I correct in the assumption that you cannot change and persist a value in your app.config for use next time you run the app? – user360943 Sep 02 '11 at 14:29

score 2 · Answer 2 · edited Sep 27 '11 at 18:48

2

Looking here: How to change App.config file run time using C# is the answer - while running in the visual studio IDE, you will not see the values persisted in the /bin/appname.exe.config. You actually have to go into the bin directory and run the exe.

So this code actually works, just not in debug mode:

Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);

config.AppSettings.Settings["ThresholdDate"].Value = Convert.ToString(testdate);
config.Save(ConfigurationSaveMode.Modified);
ConfigurationManager.RefreshSection("appSettings");

edited Sep 27 '11 at 18:48

Matthieu

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answered Sep 02 '11 at 19:58

user360943

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if it solved your issue, you should mark this as your accepted answer (48hrs timer should be expired now) – Matthieu Sep 27 '11 at 17:45

score -1 · Answer 3 · answered May 15 '12 at 03:45

Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);

config.AppSettings.Settings["ThresholdDate"].Value = Convert.ToString(testdate);
config.Save(ConfigurationSaveMode.Modified);
ConfigurationManager.RefreshSection("appSettings");

this will work only while your not in debuging mode. try to run yung code in /debug/appName.exe and the you will se the changes in appName.exe.config

cheers!

Updating a value in a local app.config

3 Answers3