InvoiceManagementStudio

Compilation prerequisite

Requires PostgreSQL database:

• dll,
• test data

Database configuration in file: App.config.

Background

IVMS was created as a term project at university Wyższa Szkoła Ekonomii i Informatyki w Krakowie as a subject of Programming in C# labs.

Requirements

• C# - Programing language.
• WPF - Desktop application.
• GitHub - Project VC.
• Team - Of 2 or more.

Short Description

Invoice Management Studio is a simple desktop application created to manage invoices. Provides simple CRUD operations on its resources and local persistance in database.

Technologies used

We aimed to use as few frameworks and libraries as possible to grasp as mutch of vanilla C# as possible.

• C#,
• WPF.
• Postgresql database,
• Npgsql - As connection and operation library for managing PostgreSQL database.

Application architecture

To keep our code clean and well organized we spend quite a lot of time designing application architecture.

We used Hexagonal architecture to separate different layers of logic.

Core

An application root and definition, provides:

• domain objects shared between different layers,
• component intefaces, providing abstract communication api between layers.

By using this approach we can simplify project structure in a way that Service layer does not know about existence of Repository layer. It only knows of abstract interface provided by Core. Thanks to that if we ever decide to replace repository managing postgresql database, and use xml files instead we do not have to change any of Service layer logic, as it only uses abstractions provided in Core.

Repository

It is a layer responsible for management and communication with PostgreSQL database.

1. Entity objects

   • provide definition of application resources mapped to simple type representing data stored in database row,
   • any relations to another objects are mapped into their id,
   • enum values are mapped into strings,
   • FromDomain creates entity representing a database row from a domain object.
   • ToDomain a method that supplied with object relations can create a domain obejct out of entity.

2. RowMapper

   • Classes responsible of translating database query result set into an entity object.

3. Command

   • Responsible of managing and executing query upon a database connection.

4. Repository

   • Layer communication access point. Provides methods on resources and delegates tasks to database.

Service

It is a layer concluding application business logic. Gives access to resources, and delegates user action results to specific logic engines.

Infrastructure

And application context and dependency provider. Presumably an IoC container with Dependency Injection factory. Depends on time we will be able to dedicate into project.

ViewModel

Manages and binds application domain objects with Desktop application view.

View

Provides graphical desktop interface to user.

Resources

• Invoice - application root aggregate. Represents an invoice in system with all related data.
• Invoice Item - Subject of invoice.
• Invoice Payment - Way invoice was payed off.
• Supplier - Company issuing an invoice.
• Receiver - To whom invoice is issued.
• Contact Info - Data representing a person to contact with about invoice.
• Billing Info - Company data needed to issue a invoice.
• Address - Physical address of invoice receiver.