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QtQt/C++ - Lesson 003. QSettings - How to save application settings?

Saving application settings - this is one of the first things that beginners learn when working with the Qt framework. For this purpose QSettings class that allows you to save the settings or operating system registry or a text file. In this tutorial you will use the easiest option - it is saving the settings in the operating system registry. In order to ensure the visibility of the store the settings in this tutorial use the draft of the lesson QSystemTrayIcon .

Project structure

The project is created as an application Qt Widgets, where files are created by default:

  • mainwindow.h - header file of the main application window;
  • mainwindow.cpp - source window;
  • main.cpp - the main source file from which the application starts;
  • mainwindow.ui - form of the main application window.

QtQt/C++ - Lesson 002. QSystemTrayIcon - How to minimize the application to the system tray?

Aug. 12, 2015, 11:27 a.m.

QSystemTrayIcon, Tray, qt, трей

Similar article on PyQt5/Python

Today will discuss the way to turn off the application, the Qt framework, written in, the operating system tray using QSystemTrayIcon class. This function is very useful for applications that need to run in the background for a long time mode. For example, video or audio playback application.

Therefore we will work with following questions:

  • How to teach your program minimized to tray;
  • How to make a popup menu for the tray icon of your applications;
  • How to disable this feature if it is not needed.

Data Transmission TechnologiesDELL Networking. VLAN Configuring

Aug. 11, 2015, 11:12 a.m.

DELL, vlan, voice vlan

Configuring VLAN for DELL switches (depending on the version of the OS switch syntax may vary slightly.

Before you configure the VLAN on the switch interfaces, you must make the switch in the VLAN database and create a VLAN interface:

console(config)# vlan database
console(config-vlan)# vlan 1972
console(config-vlan)# end
console(config)# interface vlan 1972
console(config-if)# name Marketing
console(config-if)# end

Data Transmission TechnologiesDELL Networking. MLAG Protocol

Aug. 10, 2015, 10:59 a.m.


Campus Switching Architecture

Dell switches networking N-series are based on a modern architecture of campus networks

  1. Support loop redundancy without the use of STP by using MLAG protocol to create increased access to resources and high bandwidth.
  2. Smooth interoperability with existing infrastructure for greater compatibility and integration.
  3. Combining a variety of network products with the latest open standards protocol for more choice in network.

Campus architecture on Dell switches based on functional MLAG protocol launched in version 6.1 operating system, Dell Switches. In this architecture, the two switches N4064F as peers aggregate access switches, which are combined in two stacks as well as peers. Each stack switch maintains a portion of one floor in the building of the campus, which is aggregated with two 10Gbit / c uplink'ami. N4064F aggregation layer switches easily support up to 24 stacks of switches. This architecture provides improved bandwidth, overcoming limitations STP to block redundant ports. Network is designed with a high redundancy in terms of link failure and switches.

QtQt/C++ - Lesson 001. QLineEdit IP Address

Available similar articles in Qt/QML and PyQt5/Python

When you will develop network applications, you may need to create form for input ip-address, but the use of a simple method setInputMask(";_"); of QLineEdit does not provide the proper result as this mask allows to enter the values of 999, 657, etc., while the IP-address of the limited number of 255.

One way to solve this problem is to use Validator .

Project structure

The project is created as an application Qt Widgets, where files are created by default:

  • - project profile;
  • mainwindow.h - header file of main window;
  • mainwindow.cpp - source code of main window;
  • main.cpp - the main source file from which the application starts;
  • mainwindow.ui - file of user interface.

Data Transmission TechnologiesDELL Networking. CLI (Command Line Interface)

Aug. 9, 2015, 10:52 a.m.


For example, DELL PowerConnect 3524

You can control the device directly via the terminal port or via a Telnet connection. If access is via a Telnet connection, ensure that the device specific IP-address, which will be used by the workstation to access the device and connect the device to use the CLI commands.

Telnet is an emulation on a TCP / IP terminal. RS-232 terminals can be virtually connected to the local device through a TCP / IP network protocol. Telnet is an alternative to the local terminal where you want the remote control of the device. The Switch supports up to 4 Telnet sessions to manage. All CLI commands can be used over a telnet session.

Data Transmission TechnologiesSDH - Synchronous Digital Hierarchy (Part 2)

Aug. 8, 2015, 3:49 a.m.


Compensation of frequency synchronization error

The pointer can not only fulfill a fixed phase shift and mismatch clock multiplexer clocked device, from which the user data is received. To compensate for this effect, the index value is periodically incremented or decremented.

Positive alignment - The pointer is incremented by one, reflecting the delay start of the next container VC-4, three bytes.

Negative alignment - to accommodate the "extra" bytes used three younger byte pointer, ie the NT box (the pointer itself fits in fields H1 and H2)

Data Transmission TechnologiesSDH - Synchronous Digital Hierarchy (Part 1)

Specific technologies PDH deficiencies have been addressed and overcome technology developers synchronous optical networks (Synchronous Optical NET, SONET), the first version of the standard which appeared in 1984. It was then standardized Committee of T-1 ANSI Institute. As a result of long work ITU-T and ETSI managed to prepare an international standard SDH (Synchronous Digital Hierarchy - Synchronous Digital Hierarchy).

The main goals of SDH developers were:

  • Continuity of existing digital channels T1-T3, E1-E3
  • Ensuring the hierarchy of speeds far exceeding the speed of plesiochronous digital hierarchy (PDH)

Data Transmission TechnologiesPDH - plesiochronous digital hierarchy

PDH technology was developed in the late 60s by AT & T to address the problem of large communication switches, telephone networks among themselves. Communication links the FDM, applied previously to solve this problem, have exhausted their opportunities in terms of organization of high-speed multi-channel communication over a single cable. The FDM technology for the simultaneous transmission of 12 user channels used twisted pair, and had to lay cables with a large number of pairs of wires or coaxial cables are more expensive to increase the communication speed.

Data Transmission TechnologiesDWDM Technology

The technology packed wavelength division multiplexing (Dense Wave Division Multiplexing, DWDM) is designed to create a new generation of optical backbones running at multi-terabit speeds and. Information in fiber-optic communication lines passed at the same time a large number of light waves. DWDM networks operate on the principle of channel switching, each light wave is a single spectral channel and is essential information.

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June 5, 2020, 2:25 p.m.

C++ - Test 001. The first program and data types

  • Result:33points,
  • Rating points-10
June 5, 2020, 1:09 p.m.
Artem Kin'ko

C ++ - Test 004. Pointers, Arrays and Loops

  • Result:0points,
  • Rating points-10
June 5, 2020, 2:28 a.m.

Qt - Test 001. Signals and slots

  • Result:0points,
  • Rating points-10
Last comments
June 5, 2020, 10:52 a.m.

Распознавание изображений на Python с помощью TensorFlow и Keras

Огромное спасибо за метериал, по-больше бы подобных статей (с подробным описанием работы и примерами применения) на тему современных технологий. Вопрос поразмышлять. На текущий момент реал…
June 5, 2020, 1:39 a.m.
Evgenij Legotskoj

Qt/C++ - Tutorial 091. How to write a custom delegate controlling the highlighting of a row in a table

По-моему, смысла в этом нет особого. Если делегат будет игнорировать настройки таблицы, то это приведёт ещё к большему непониманию, что вообще происходит, для программиста, который после вас буд…
June 5, 2020, 1:34 a.m.

Qt/C++ - Tutorial 091. How to write a custom delegate controlling the highlighting of a row in a table

Сижу, размышляю: можно ли переписать делегата так, чтобы независимо от настроек строк выделялись строки?
June 5, 2020, 1:31 a.m.
Evgenij Legotskoj

Qt/C++ - Tutorial 091. How to write a custom delegate controlling the highlighting of a row in a table

Понятно. Я не обратил внимания на то, что там было в старом коде по настройкам строк :)
Now discuss on the forum
June 5, 2020, 1:09 p.m.

QPlainTextEdit настройка цвета фона

Вечер добрый. Пытаюсь настроить цвет фона QPlainTextEdit следующим образом: CodeEditor::CodeEditor(QWidget *parent) : QPlainTextEdit(parent){ ... QPalette::ColorRole role = bac…
June 5, 2020, 6:13 a.m.

Фильтр для QtableView sql

Добрый день. Для такой фильтрации необходимо использовать QSortFilterProxyModel. В оффдоках есть хороший пример.
June 4, 2020, 2:46 a.m.
Mihail A

Qt- C++ QTableView подсветить строку

June 3, 2020, 1:49 a.m.

Можно ли сделать в QML таблицу как в Excel?

edi-tableview - нашел пока такое выглядит коряво, посмотрим что можно сделать
June 2, 2020, 2:46 a.m.
Evgenij Legotskoj

Медиа файлы Google Firebase

Картинки можете попробовать сжимать через QPixmap, там есть возможность установки scaleFactor, через него можете устанавливать нужные параметры. А что касается конвертации видео, то лучше п…
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