Switching or Selecting Database Server's Connection String Best Practices - sql-server

Question

I'm developing a software that will be used in different locations with different Servers. It differs in Server Name, Database name, etc.
Example:
Location 1 : Server Name: ChinaServer; Database Name: ChinaDB
Location 2 : Server Name: USServer; Database Name: USDB
Currently, I am using .ini file, I store the server name, database name and other configurations to it. I read it and use it runtime for my connection string. The problem here is that every time we switch locations, I need to change/edit the .ini file.
I'm asking everyone that has more experience that mine to give me other options or best approach on this matter.
Client's Environment : Windows 7
Developers : Windows 7, Visual Studio 2015, MS SQL, VB.NET
Thanks IA.

Answer 1

There's a couple of ways, each with their own advantages and disadvantages, the configuration file would work, could also store it in the registry of the server and read it that way. Or you could even use a My.Setting variable that can be updated in a settings page (probably not the most suitable for your situation)

Answer 2

You can get the basic idea from the The Twelve-Factor App "manifesto":
The twelve-factor app stores config in environment variables...
So what you need is to establish a machine-wide (setx /M NAME VALUE) environment variable which you'll later use like this:
var connectionString = Environment.GetEnvironmentVariable("MY_APP_CONNECTION_STRING");
var dbContext = new DbContext(connectionString);

Answer 3

You can use the SQL Server enumerator in System.Data.Sql, and run a query to get the database names. From there bind those lists to combo boxes, and use a SqlConnectionStringBuilder to keep track of your connection settings. You can save them to disk, or just ask the user to choose the server and database. Note that the enumerator is not guaranteed to always find all servers, so make sure you have a way to enter it manually if necessary.
private SqlConnectionStringBuilder _connString = new SqlConnectionStringBuilder();
private void RefreshConnectionString()
{
_connString.ApplicationName = AppDomain.CurrentDomain.ApplicationIdentity.FullName;
_connString.ApplicationIntent = ApplicationIntent.ReadWrite;
_connString.DataSource = GetSqlDatasources().FirstOrDefault();
_connString.InitialCatalog = GetSqlDatabases().FirstOrDefault();
_connString.AsynchronousProcessing = true;
_connString.ConnectTimeout = 5;
_connString.IntegratedSecurity = true;
_connString.Pooling = true;
}
private IEnumerable<string> GetSqlDatabases()
{
using (var conn = new SqlConnection(_connString.ConnectionString))
{
using (var cmd = new SqlCommand(#"SELECT [name] FROM sys.databases WHERE [name] NOT IN ('master', 'model', 'msdb', 'tempdb')", conn))
{
var dbnames = new List<string>();
try
{
conn.Open();
var reader = cmd.ExecuteReader();
while (reader.Read()) dbnames.Add(reader.GetString(0));
}
catch {}
return dbnames;
}
}
}
private IEnumerable<string> GetSqlDatasources()
{
var sqlEnum = SqlDataSourceEnumerator.Instance;
return sqlEnum.GetDataSources().Rows.OfType<DataRow>().Select(row => row[0].ToString());
}