Reading from a app.config file - c#

I am trying to print to Console.Write the value of the key name from the following app.config file.
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<appSettings>
<add key="name" value="Chan" />
</appSettings>
</configuration>
C# code :
Console.Write(ConfigurationManager.AppSettings["name"]);
Nothing gets printed in the console. Why is this ?
Note: I have added a reference to the System.Configuration dll


below code gives you the content of active config file.
var content = File.ReadAllLines(AppDomain.CurrentDomain.SetupInformation.ConfigurationFile);
Check what you get as content, is it contain key="name" value="Chan" or something else
?
if you given <add key="name" value="Chan" /> then
ConfigurationManager.AppSettings["name"] should return as Chan


Given that your XML file (app.config) is properly formatted, try below.
Declare a variable and assign the variable the AppSettings value. Similar like-
string sName = "";
sName = ConfigurationManager.AppSettings["name"].ToString();

Related

How to stop config file from throwing errors because of symbols? [duplicate]

Following config file causes error because of & in 'url' value:
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<appSettings>
<add key ="url" value ="http://www.example.com/?user=admin&password=1234"/>
</appSettings>
</configuration>
The question is which encoding to use for key/value in a config file ? (i.e Url Encoding ...)

This is an XML file. As such, you must XML-escape all reserved characters:
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<appSettings>
<add key ="url" value ="http://www.example.com/?user=admin&password=1234"/>
</appSettings>
</configuration>
Programmatically you can perform this type of escaping using the System.Web.HttpUtility.HtmlEncode method. Yes, its name suggests HTML specific encoding, but in my experience this is equivalent to XML escaping.

Saving existing file: empty value attribute is removed

I have a config file like this:
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<appSettings>
<add key="key1" value="value1" />
<add key="key2" value="" />
...
</appSettings>
...
</configuration>
I read the config, change the value of key1 and save the config
System.Configuration.Configuration appConfig = ConfigurationManager.OpenExeConfiguration(Configuration.ConfigFile.Replace(".config", string.Empty));
appConfig.AppSettings.Settings["key1].Value = "newvalue1";
appConfig.Save(ConfigurationSaveMode.Minimal);
After this I get the following result:
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<appSettings>
<add key="key1" value="newvalue1" />
<add key="key2"/>
...
</appSettings>
...
</configuration>
Why is the 'empty' value attribute removed for key "key2"?
When I try it with
appConfig.Save(ConfigurationSaveMode.Modified);
, the attribute is not removed. But I want to know why it's removed in the first case?
Thanks

<add key="key2" value="" />
and
<add key="key2" />
are both functionally equal. The value of key2 with or without that tag is a null string variable which is equivalent to the empty string.
Edit to reflect comment: Simply assign key2 the empty string in the same statement.
System.Configuration.Configuration appConfig = ConfigurationManager.OpenExeConfiguration(Configuration.ConfigFile.Replace(".config", string.Empty));
appConfig.AppSettings.Settings["key1"].Value = "newvalue1";
appConfig.AppSettings.Settings["key2"].Value = "";
appConfig.Save(ConfigurationSaveMode.Minimal);
Second Edit for 2nd comment:
Well, you haven't provided enough information then. All of my answers answer your question. The two values from the first answer are functionally equivalent. Therefore, if you wish to see if the "key2" value = "" then you could simply run the following
if(appConfig.AppSettings.Settings["key2"] == null){
//If this hits, that means <add key="key2" value="" />
}
Please research how to ask a good question and adjust your question to reflect what you are really trying to ask.

Error : The key 'SecurityKey' does not exist in the appSettings configuration section

When I execute my app (Winform)from the computer where it was developed there is no error, but When I execute this in another computer I get the error. My App.config is like this:
<?xml version="1.0"?>
<configuration>
<appSettings>
<add key="SecurityKey"/>
</appSettings>
<startup>
<supportedRuntime version="v4.0"sku="...."/>
</startup>
</configuration>
and this is the line that I use:
string key = (string)settingsReader.GetValue("SecurityKey", typeof(String));
I already tried to follow this The key 'UserID' does not exist in the appSettings configuration section, but it is still the same.
Any suggestions?

the appSettings in the .config file is different from .settings file.
Take a look at ConfigurationManager.AppSettings Property.
I'd also mention that I have no idea how either the settingsReader nor the ConfigurationManager work with a key with no value:
<add key="SecurityKey"/> <!-- no value? -->
<add key="SecurityKeyWithValue" value="myvalue"/>

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<appSettings>
<add key="SecurityKey" value="Syed Moshiur Murshed"/>
</appSettings>
</configuration>

My config file for dll or why cannot parse Section..?

I encountered a problem that I have no way to parse a document standard configurations.
For example:
private string GetConfigKey(string param)
{
Configuration dllConfig = ConfigurationManager.OpenExeConfiguration(this.GetType().Assembly.Location);
AppSettingsSection dllConfigAppSettings = (AppSettingsSection)dllConfig.GetSection("appSettings");
return dllConfigAppSettings.Settings[param].Value;
}
As a result, I get the settings from the file in a form:
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<appSettings>
<add key="host" value="mail.ololo.by"/>
</appSettings>
<configSections>
<section name="provideConfig" type="System.Configuration.DictionarySectionHandler"/>
<section name="provideMailStatus" type="System.Configuration.DictionarySectionHandler" />
</configSections>
<provideConfig>
<add key="post#gate.ololo.by" value="Mail Subject 1"/>
<add key="guga#gate.ololo.by" value="Mail Subject 2"/>
</provideConfig>
<provideMailStatus>
<add key="status1" value="send"/>
<add key="status2" value="draft"/>
<add key="status2" value="other"/>
</provideMailStatus>
</configuration>
but
Hashtable hashtable =
(Hashtable)ConfigurationManager.GetSection("provideConfig");
foreach (DictionaryEntry dictionaryEntry in hashtable)
{
Console.WriteLine(dictionaryEntry.Key+" "+dictionaryEntry.Value);
}
but that's unfortunately a configSections have a problem. I can not seem to get it.
MB, I go in the wrong direction?
P.S. Config file cannot be named "app.config" - only project dll name

Config file should be named as executable file name and ".config". Even this executable file uses this dll-file.
For example: ConSoleApplication.exe uses MyLibrary.dll. Then config file must be named ConSoleApplication.exe.config
If You need some other name for config file read this

Thank you all, I coped with the problem.
I can tell if someone will be interested.
Configuration Section Designer Codeplex
.NET Configuration Code Generator
Best regards, yauhen.

Which encoding to use in App.Config?

Following config file causes error because of & in 'url' value:
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<appSettings>
<add key ="url" value ="http://www.example.com/?user=admin&password=1234"/>
</appSettings>
</configuration>
The question is which encoding to use for key/value in a config file ? (i.e Url Encoding ...)

This is an XML file. As such, you must XML-escape all reserved characters:
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<appSettings>
<add key ="url" value ="http://www.example.com/?user=admin&password=1234"/>
</appSettings>
</configuration>
Programmatically you can perform this type of escaping using the System.Web.HttpUtility.HtmlEncode method. Yes, its name suggests HTML specific encoding, but in my experience this is equivalent to XML escaping.

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