Test multiple SQL Server connection strings in a dotnet console app

connection-string-tester.cs

// Source: https://ainab.site/2021/12/09/test-multiple-sql-server-connection-strings-in-a-dotnet-console-app/

using System.Data.SqlClient;
class Credentials
{
    public string Username { get; set; }
    public string Password { get; set; }
    public string Server { get; set; }
    public Credentials(string username, string password, string server = "sql-server.example.com") {
        Username = username;
        Password = password;
        Server = server;
    }
    public string GenerateConnectionString()
    {
        return $"Server=tcp:{Server},1433;Initial Catalog=defaultDatabase;Persist Security Info=False;User ID={Username};Password={Password};MultipleActiveResultSets=False;Encrypt=True;TrustServerCertificate=False;Connection Timeout=30;";
    }
}
class Program
{
    static void Main(string[] args)
    {
        List<Credentials> credentialsCollection = new List<Credentials>
        {
            new Credentials("login-one", "complex-password"),
            new Credentials("login-two", "complex-password"),
            new Credentials("login-three", "complex-password")
        };
        foreach (var credentials in credentialsCollection)
        {
            TestConnectionString(credentials);
        }
    }
    // Source: https://stackoverflow.com/a/1497110/4496102
    static void TestConnectionString(Credentials credentials)
    {
        SqlConnection? conn = null;
        var connectionString = credentials.GenerateConnectionString();
        try
        {
            conn = new SqlConnection(connectionString);
            conn.Open();
            Console.WriteLine("good connection string");
        }
        catch (SqlException sqlE)
        {
            Console.WriteLine($"bad connection string: {credentials.Username}");
        }
        finally
        {
            if (conn != null) conn.Dispose();
        }
    }
}