C#

public interface IRepository<T> where T : class
{
    void Add(T entity);
    void AddRange(IEnumerable<T> entities);
    void Delete(T entity);
    void DeleteRange(IEnumerable<T> entities);
    T Get(int id);
    IEnumerable<T> Get(Expression<Func<T, bool>> expression);
    IEnumerable<T> GetAll();
}

public class BaseRepository<T> : IRepository<T> where T : class
{
    protected readonly DbContext _context;

    public BaseRepository(DbContext context)
    {
        _context = context;
    }

    // Interface methods here
}

public class CustomerRepository : BaseRepository<CustomerEntity>, ICustomerRepository
{
    public CustomerRepository(DbContext context)
        :base(context)
    {
    }

    public bool IsCustomerActive(int id)
    {
        return true;
    }
}

public class CustomerController : ControllerBase
{
    public bool CheckIfCustomerIsActive(int id)
    {
        var connString = "";

        var dc = new SqlDataContext(connString);

        ICustomerRepository repository = new CustomerRepository(dc);

        return repository.IsCustomerActive(id);
    }
}

public class BaseRepository<T> : IRepository<T> where T : class
{
    protected readonly DbContext _context;

    public BaseRepository()
    {
        // The base repo is the only place that gets the connection string
        var connString = Properties.Settings.Default.ConnectionString;

        // The base repo is the only place that knows about the db context
        _context = new SqlDataContext(connString);
    }

    // Interface methods here
}

I a'm reading values from raspberry pi mysql database with visual studio c#
If the database is not available and I am trying to read from it, the c# app
freezes for about 15 seconds. 

Is it possible to make it not to freeze when checking if the database is available?

Her is the code
<pre lang="C#">string connString = "SERVER='192.168.86.41';DATABASE='spaceinformation';UID='******';PASSWORD='******'";
 private void FormMeasurement_Load(object sender, EventArgs e)
        {
            try
            {
                using (var connection = new MySqlConnection(connString))
                {
                    connection.Open();

                    query = "select * from weather";
                    using (var command = new MySqlCommand(query, connection))
                    {
                        using (var reader = command.ExecuteReader())
                        {
                            while (reader.Read())
                            {
                                listBoxMeasurement.Items.Add(string.Format("Temperature: {0}   Humidity: {1}   Date: {2}", reader.GetString("temp"), reader.GetString("hum"), reader.GetString("datecreated")));
                            }
                        }
                    }
                    connection.Close();
                }
            }
            catch
            {
                MessageBox.Show("Database is not available for moment!");
                listBoxMeasurement.Enabled = false;
            }
        }