The simple tool for easy reading .NET configuration file (web.config, app.config) into the immutable class of settings.
First you should define immutable class of settings. This class should have a single constructor with parameters named like the parameters in configuration file.
public class UserSettings
{
public UserSettings(string login, string password, int age, bool needConfirmation)
{
Login = login;
Password = password;
Age = age;
}
public string Login { get; private set; }
public string Password { get; private set; }
public int Age { get; private set; }
public bool NeedConfirmation { get; private set; }
}app.config file:
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<appSettings>
<add key="Login" value="admin" />
<add key="Password" value="passw0rd" />
<add key="Age" value="23" />
</appSettings>
</configuration>And then you simply read the settings from configuration file into object.
var userSettings = AppConfigReader.ReadFromAppSettings<UserSettings>();
loginService.Login(userSettings);You can define default values in constructor using nullable types.
public class UserSettings
{
public UserSettings(string login, string password, int? age, bool? needConfirmation, int? timeoutInSeconds)
{
Login = string.IsNullOrEmpty(login) ? "mrBond" : login;
Password = password;
Age = age;
NeedConfirmation = needConfirmation ?? true;
TimeoutInSeconds = timeoutInSeconds ?? 10;
}
public string Login { get; private set; }
public string Password { get; private set; }
public int? Age { get; private set; }
public bool NeedConfirmation { get; private set; }
public int TimeoutInSeconds { get; private set; }
}If there's no value in configuration file, or the value of parameter is not valid, then we get default value for parameter type. For example, for int type we'll get 0, for bool - false, for double? - null.
You can read array values separated by semicolon.
app.config file:
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<appSettings>
<add key="Numbers" value="1;234;-23;45" />
</appSettings>
</configuration> public class UserSettings
{
public UserSettings(IEnumerable<int> numbers)
{
Numbers = numbers;
}
public IEnumerable<int> Numbers { get; private set; }
}You can write key-value settings in custom section.
app.config file:
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<appSettings>
</appSettings>
<user>
<add key="Login" value="admin" />
<add key="Password" value="passw0rd" />
<add key="Age" value="23" />
</user>
</configuration>For read this settings into object use another method:
var userSettings = AppConfigReader.ReadFromSection<UserSettings>("user");If you have settings as key-value collection, you can also read them into settings object. The main purpose of it is reading settings from custom data sources.
var collection = new KeyValueConfigurationCollection()
{
new KeyValueConfigurationElement("Login", "mrBond"),
new KeyValueConfigurationElement("Password", "testtest"),
new KeyValueConfigurationElement("Age", "7")
};
var userSettings = ConfigurationReader<UserSettings>.ReadFromCollection(collection);The parameters of constructor in settings class could be:
- string
- int
- double
- bool
and IEnumerable<> of this types.
You can simply use readers with IoC containers. Here's example with Autofac:
public static class AutofacExtension
{
public static void RegisterReaderFromAppSettings<T>(this ContainerBuilder builder) where T : class
{
builder.Register(c => AppConfigReader.ReadFromAppSettings<T>())
.AsSelf()
.SingleInstance();
}
} builder = new ContainerBuilder();
...
builder.RegisterReaderFromAppSettings<UserSettings>();
var container = builder.Build();