Tutorial by Examples: s

var sourceFileName = "NonExistingFile"; try { System.IO.File.Copy(sourceFileName, "DestinationFile"); } catch (Exception e) { var stdErr = Console.Error; stdErr.WriteLine($"Failed to copy '{sourceFileName}': {e.Message}"); }

var errors = new System.Text.StringBuilder(); var process = new Process { StartInfo = new ProcessStartInfo { RedirectStandardError = true, FileName = "xcopy.exe", Arguments = "\"NonExistingFile\" \"DestinationFile\"", ...

To get the list of Elixir modules just type h Elixir.[TAB] Pressing [TAB] autocompletes modules and functions names. In this case it lists all modules. To find all functions in a module e.g. List use h List.[TAB]

For rendering multiple props or variables we can use ``. render() { let firstName = 'test'; let lastName = 'name'; return ( <View style={styles.container}> <Text>{`${firstName} ${lastName}` } </Text> </View> ); } Output: te...

php -S localhost:80 PHP 7.1.7 Development Server started at Fri Jul 14 15:11:05 2017 Listening on http://localhost:80 Document root is C:\projetos\repgeral Press Ctrl-C to quit. This is the simplest way to start a PHP server that responds to request made to localhost at the port 80. The -S...

php -S localhost:80 -t project/public router.php PHP 7.1.7 Development Server started at Fri Jul 14 15:22:25 2017 Listening on http://localhost:80 Document root is /home/project/public Press Ctrl-C to quit.

The PXDBTimeSpan attribute is designed to work with a DAC field of the Nullable<int> (int?) type and store time value inside a DAC field as the number of minutes passed since midnight: #region UsrTimeInt public abstract class usrTimeInt : IBqlField { } [PXDBTimeSpan(DisplayMask = "t...

The PXTimeList attribute is designed to work with a DAC field of the Nullable<int> (int?) type and store time span value inside a DAC field as a number of minutes: #region UsrTimeSpan public abstract class usrTimeSpan : IBqlField { } [PXDBInt] [PXTimeList] [PXUIField(DisplayName = &quo...

This returns a map without the key-value pairs for the keys mentioned in the function argument. It can be used to remove information from existing map. (dissoc {:a 1 :b 2} :a) ;; {:b 2} It can also be used for dissocing multiple keys as: (dissoc {:a 1 :b 2 :c 3} :a :b) ;; {:c 3}

This is ANSI SQL method works in all the RDBMS. Widely used approach. CREATE TABLE AliasNameDemo (id INT,firstname VARCHAR(20),lastname VARCHAR(20)) INSERT INTO AliasNameDemo VALUES (1,'MyFirstName','MyLastName') SELECT FirstName +' '+ LastName As FullName FROM AliasNameDemo

This is my preferred approach. Nothing related to performance just a personal choice. It makes the code to look clean. You can see the resulting column names easily instead of scrolling the code if you have a big expression. CREATE TABLE AliasNameDemo (id INT,firstname VARCHAR(20),lastname VARCHAR(...

This is a weird approach most of the people don't know this even exist. CREATE TABLE AliasNameDemo(id INT,firstname VARCHAR(20),lastname VARCHAR(20)) INSERT INTO AliasNameDemo VALUES (1,'MyFirstName','MyLastName') SELECT * FROM (SELECT firstname + ' ' + lastname FROM A...

This syntax will be similar to using AS keyword. Just we don't have to use AS keyword CREATE TABLE AliasNameDemo (id INT,firstname VARCHAR(20),lastname VARCHAR(20)) INSERT INTO AliasNameDemo VALUES (1,'MyFirstName','MyLastName') SELECT FirstName +' '+ LastName FullName FROM AliasNa...

├───models │ ├───user.model.js ├───routes │ ├───user.route.js ├───services │ ├───user.service.js ├───controllers │ ├───user.controller.js For modular code structure the logic should be divided into these directories and files. Models - The schema definition of the Model Rou...

user.model.js var mongoose = require('mongoose') const UserSchema = new mongoose.Schema({ name: String }) const User = mongoose.model('User', UserSchema) module.exports = User; user.routes.js var express = require('express'); var router = express.Router(); var UserController...

If the promise doesn't return anything, the async task can be completed using await. try{ await User.findByIdAndUpdate(user._id, { $push: { tokens: token } }).exec() }catch(e){ handleError(e) }

The ObservableObject class contains some helpful methods to help with the MVVM pattern. The RaisePropertyChanged provides a compile safe method to raise property changed events. It can be called with RaisePropertyChanged(() => MyProperty); The Set method can be used in the property setter t...

ViewModelBase extends ObservableObject and adds some methods useful for viewmodels. The property IsInDesignMode or IsInDesignModeStatic allows to determine if the code is executed in the design mode (in Visual Studio Design View) or not. The two properties are exactly the same.

Tables are most easily included with the DT package, which is an R interface to the JavaScript library DataTables. library(shiny) library(DT) ui <- fluidPage( dataTableOutput('myTable') ) server <- function(input, output, session){ output$myTable <- renderDataTable({ dat...

reactiveValues can be used to store objects, to which other expressions can take a dependency. In the example below, a reactiveValues object is initialized with value "No text has been submitted yet.". A separate observer is created to update the reactiveValues object whenever the submit ...