Да, вы можете определенно добавлять / изменять / удалять настройки в app.config во время выполнения. Вот как я обычно это делаю.
using System.Configuration; // don't forget to add the system.configuration dll to your references.
public static void CreateConnectionString(string datasource, string initialCatalog, string userId, string password)
{
try
{
//Integrated security will be off if either UserID or Password is supplied
var integratedSecurity = string.IsNullOrEmpty(userId) || string.IsNullOrEmpty(password);
//Create the connection string using the connection builder
var connectionBuilder = new SqlConnectionStringBuilder
{
DataSource = datasource,
InitialCatalog = initialCatalog,
UserID = userId,
Password = password,
IntegratedSecurity = integratedSecurity
};
//Open the app.config for modification
var config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
//Retreive connection string setting
var connectionString = config.ConnectionStrings.ConnectionStrings["ConnectionStringName"];
if (connectionString == null)
{
//Create connection string if it doesn't exist
config.ConnectionStrings.ConnectionStrings.Add(new ConnectionStringSettings
{
Name = ConnectionName,
ConnectionString = connectionBuilder.ConnectionString,
ProviderName = "System.Data.SqlClient" //Depends on the provider, this is for SQL Server
});
}
else
{
//Only modify the connection string if it does exist
connectionString.ConnectionString = connectionBuilder.ConnectionString;
}
//Save changes in the app.config
config.Save(ConfigurationSaveMode.Modified);
}
catch (Exception)
{
//TODO: Handle exception
}
}
Надеюсь, это поможет.