Tutorial by Examples: le

Setting state Added of a single entity

EntityState.Added can be set in two fully equivalent ways: By setting the state of its entry in the context: context.Entry(entity).State = EntityState.Added; By adding it to a DbSet of the context: context.Entities.Add(entity); When calling SaveChanges, the entity will be inse...

Entity Framework • Managing entity state

delegate

Delegates are types that represent a reference to a method. They are used for passing methods as arguments to other methods. Delegates can hold static methods, instance methods, anonymous methods, or lambda expressions. class DelegateExample { public void Run() { //using class ...

C# Language • Keywords

The Other Looping Constructs: while and repeat

R provides two additional looping constructs, while and repeat, which are typically used in situations where the number of iterations required is indeterminate. The while loop The general form of a while loop is as follows, while (condition) { ## do something ## in loop body } whe...

R Language • Control flow structures

Reading/Writing Data Using System.IO.File

First, let's see three different ways of extracting data from a file. string fileText = File.ReadAllText(file); string[] fileLines = File.ReadAllLines(file); byte[] fileBytes = File.ReadAllBytes(file); On the first line, we read all the data in the file as a string. On the second line, we r...

.NET Framework • System.IO

In-place replacement of a List element

This example is about replacing a List element while ensuring that the replacement element is at the same position as the element that is replaced. This can be done using these methods: set(int index, T type) int indexOf(T type) Consider an ArrayList containing the elements "Program sta...

Java Language • Lists

Ajax File Uploads

1. A Simple Complete Example We could use this sample code to upload the files selected by the user every time a new file selection is made. <input type="file" id="file-input" multiple> var files; var fdata = new FormData(); $("#file-input").on("cha...

jQuery • Ajax

Load local HTML file in webView

First, add the HTML File to your Project (If you are asked to choose options for adding the file, select Copy items if needed) The following line of code loads the content of the HTML file into the webView webView.loadRequest(NSURLRequest(URL: NSURL(fileURLWithPath: NSBundle.mainBundle().pathForRe...

iOS • UIWebView

Uploading Files

Images and files can be uploaded/submitted to server by setting enctype attribute of form tag to multipart/form-data. enctype specifies how form data would be encoded while submitting to the server. Example <form method="post" enctype="multipart/form-data" action="uplo...

HTML • Forms

Example: current UNIX time

Here is a very simple example to illustrate how to write a NIF. Directory structure: nif_test ├── c_src │ ├── Makefile │ └── nif_test.c ├── rebar.config └── src ├── nif_test.app.src └── nif_test.erl This structure can be easily initialized using Rebar3: $ rebar3 new lib nif_...

Erlang Language • NIFs

Low Level API Example

var client = new AmazonDynamoDBClient(); // Store item client.PutItem(new PutItemRequest { TableName = "Books", Item = new Dictionary<string, AttributeValue> { { "Title", new AttributeValue { S = "Cryptonomicon" } }, { "...

amazon-dynamodb • Using AWS DynamoDb with the AWS .NET SDK

Document Model Example

var client = new AmazonDynamoDBClient(); Table booksTable = Table.LoadTable(client, "Books"); // Store item Document book = new Document(); book["Title"] = "Cryptonomicon"; book["Id"] = 42; book["Authors"] = new List<string> { "Ne...

amazon-dynamodb • Using AWS DynamoDb with the AWS .NET SDK

Object Persistence Model Example

This example consists of two parts: first, we must define our Book type; second, we use it with DynamoDBContext. [DynamoDBTable("Books")] class Book { [DynamoDBHashKey] public int Id { get; set; } public string Title { get; set; } public List<string> Authors { ...

amazon-dynamodb • Using AWS DynamoDb with the AWS .NET SDK

Making a list unmodifiable

The Collections class provides a way to make a list unmodifiable: List<String> ls = new ArrayList<String>(); List<String> unmodifiableList = Collections.unmodifiableList(ls); If you want an unmodifiable list with one item you can use: List<String> unmodifiableList = Col...

Java Language • Lists

Sources and Handlers

What are events? VBA is event-driven: VBA code runs in response to events raised by the host application or the host document - understanding events is fundamental to understanding VBA. APIs often expose objects that raise a number of events in response to various states. For example an Excel.Appl...

VBA • Events

creating a UDT with a single int column that is also a primary key

CREATE TYPE dbo.Ids as TABLE ( Id int PRIMARY KEY )

Microsoft SQL Server • User Defined Table Types

Creating a UDT with multiple columns

CREATE TYPE MyComplexType as TABLE ( Id int, Name varchar(10) )

Microsoft SQL Server • User Defined Table Types

Getting started with a simple map

<html> <head> <title>Getting started</title> <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/ol3/3.17.1/ol.css" type="text/css"> <script src="https://cdnjs.cloudflare.com/ajax/libs/ol3/3.17.1/ol...

openlayers-3 • Getting started with openlayers-3

Using a table valued parameter to insert multiple rows to a table

First, define a used defined table type to use: CREATE TYPE names as TABLE ( FirstName varchar(10), LastName varchar(10) ) GO Create the stored procedure: CREATE PROCEDURE prInsertNames ( @Names dbo.Names READONLY -- Note: You must specify the READONLY ) AS INSERT INTO d...

Microsoft SQL Server • Table Valued Parameters

Defining a basic module

Java Language • Modules

Using the right-left or spiral rule to decipher C declaration

The "right-left" rule is a completely regular rule for deciphering C declarations. It can also be useful in creating them. Read the symbols as you encounter them in the declaration... * as "pointer to" - always on the left side [] as "array of" ...

C Language • Declarations