Komiyama

using (SqlConnection conn = new SqlConnection("ConnectionString"))

{

    SqlCommand cmd = new SqlCommand("SPName", conn);

    cmd.CommandType = CommandType.StoredProcedure;

    conn.Open();

    SqlCommandBuilder.DeriveParameters(cmd);

    foreach (SqlParameter parameter in cmd.Parameters)

    {

        if (parameter.Direction == ParameterDirection.Input || parameter.Direction == ParameterDirection.InputOutput)

        {

            Console.WriteLine(parameter.ParameterName);                        

        }

    }

}