It is necessary to develop a very basic desktop application “Internet Provider” in C# + Windows Forms + SQLite, which allows managing a database of clients, tariffs, payments, and technical support requests, and displaying statistics on the main screen.

The application should have a main window with a navigation menu and variable pages (UserControl).

2. Technologies

The developer must use:

• C#

• .NET Framework or .NET 6/7 WinForms

• Windows Forms

• SQLite (database file .db)

• ADO.NET or Dapper (ORM is not mandatory)

• Visual Studio

3. Application Structure

The main window contains:

• Side menu with buttons:

  • Main

  • Clients

  • Tariffs

  • Payments

  • Requests

• Panel for changing pages (MainPanel)

• Header at the top (labelTitle), text changes depending on the selected page

Transition between sections should not create new windows — a UserControl system is used.

4. Application Sections (UserControl)

✔ 4.1. Main

The screen displays statistics:

• Total clients

• Active clients

• Disconnected

• Tariffs

• New requests

• Requests in progress

Data is taken from the database.

✔ 4.2. Clients

Table (DataGridView):

| Full Name | Address | Phone | Email | Tariff | Status | Actions |

Functionality:

• Button “Add Client”

• A modal window opens with fields:

  • Full Name

  • Address

  • Phone

  • Email

  • Tariff (ComboBox of tariffs)

  • Status (Active/Disconnected)

  • Buttons: Save / Cancel

• CRUD:

  • Add

  • Edit

  • Delete

✔ 4.3. Tariffs

DataGridView:

| Name | Speed | Price | Description | Actions |

Functions:

• Add tariff

• Edit

• Delete

✔ 4.4. Payments

DataGridView:

| Client | Amount | Date |

Must have:

• Button “Add Payment”

• Fields:

  • Client (ComboBox)

  • Amount

  • Date (DateTimePicker)

• CRUD

✔ 4.5. Technical Support Requests

DataGridView:

| Client | Description | Date | Status | Change Status |

Statuses:

• “New”

• “In Progress”

• “Resolved”

Functions:

• Add request

• Change status

• Delete request

5. Database Structure (SQLite)

Table: clients

id INTEGER PRIMARY KEY
full_name TEXT
address TEXT
phone TEXT
email TEXT
tariff_id INTEGER
status TEXT

Table: tariffs

id INTEGER PRIMARY KEY
name TEXT
speed INTEGER
price REAL
description TEXT

Table: payments

id INTEGER PRIMARY KEY
client_id INTEGER
amount REAL
date TEXT

Table: tickets

id INTEGER PRIMARY KEY
client_id INTEGER
problem TEXT
date TEXT
status TEXT