• یکی از محدودیت‌های استفاده از expression body داشتن چندین خط دستور برای بدنه متدهایمان است. در اینحالت باید از روش سابق (statement body) استفاده نمائید. 
• یکی دیگر از محدودیت‌ها عدم امکان استفاده از if, else, switch است. به عنوان مثال نمی‌توان کد زیر را با داشتن if و else به صورت expression body نوشت:

public override string ToString() =>
                    (MiddleName != null)
                    ? FirstName + " " + MiddleName + " " + LastName
                    : FirstName + " " + LastName;

• همچنین نمی‌توان از for, foreach, while, do در expression body استفاده کرد، به جای آن می‌توان از عبارت‌های LINQ برای بدنه تابع استفاده کرد. به عنوان مثال متد زیر:
  

public IEnumerable<int> SmallNumbers() => Enumerable.Range(0, 10).Select(n => n);

• همانطور که عنوان شد، استفاده از expression body در قسمت پراپرتی‌ها تنها محدود به پراپرتی‌های get-only (فقط خواندنی) میباشد.
  
• استفاده از این قابلیت برای متدهای سازنده
• استفاده در رخدادها
• استفاده در finalizers

    public class Person
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }

        public Person()
        {
            this.FirstName = "Sirwan";
            this.LastName = "Afifi";
        }
    }

public string FirstName { get; set; } = "Sirwan";
public string LastName { get; set; } = "Afifi";

  constructor(props) {
    super(props);
    console.log("App - constructor");
    this.state = this.props.something;
  }

class App extends Component {
  constructor() {
    super();
    console.log("App - constructor");
  }

  componentDidMount() {
    // Ajax calls
    console.log("App - mounted");
  }

  render() {
    console.log("App - rendered");

class Counter extends Component {
  render() {
    console.log("Counter - rendered");
//...

class Counters extends Component {
  render() {
    console.log("Counters - rendered");
//...

const NavBar = ({ totalCounters }) => {
  console.log("NavBar - rendered");
//...

class Counter extends Component {
  componentDidUpdate(prevProps, prevState) {
    console.log("Counter - updated", { prevProps, prevState });
    if (prevProps.counter.value !== this.props.counter.value) {
      // Ajax call and get new data
    }
  }

class Counter extends Component {
  componentWillUnmount(){
    console.log("Counter - Unmount");
  }

class Counter extends Component {

  render() {
    console.log("Counter - rendered");
    return (
      <div className="row">
        <div className="col-1">
          <span className={this.getBadgeClasses()}>{this.formatCount()}</span>
        </div>
        <div className="col">
          <button
            onClick={() => this.props.onIncrement(this.props.counter)}
            className="btn btn-secondary btn-sm"
          >
            +
          </button>
          <button
            onClick={() => this.props.onDecrement(this.props.counter)}
            className="btn btn-secondary btn-sm m-2"
            disabled={this.props.counter.value === 0 ? "disabled" : ""}
          >
            -
          </button>
          <button
            onClick={() => this.props.onDelete(this.props.counter.id)}
            className="btn btn-danger btn-sm"
          >
            Delete
          </button>
        </div>
      </div>
    );
  }

<Counter
  key={counter.id}
  counter={counter}
  onDelete={this.props.onDelete}
  onIncrement={this.props.onIncrement}
  onDecrement={this.props.onDecrement}
/>

<Counters
  counters={this.state.counters}
  onReset={this.handleReset}
  onIncrement={this.handleIncrement}
  onDecrement={this.handleDecrement}
  onDelete={this.handleDelete}
/>

  handleDecrement = counter => {
    console.log("handleDecrement", counter);
    const counters = [...this.state.counters]; // cloning an array
    const index = counters.indexOf(counter);
    counters[index] = { ...counter }; // cloning an object
    counters[index].value--;
    console.log("this.state.counters", this.state.counters[index]);
    this.setState({ counters });
  };

let add x y = x + y
let result = add 4 5
printfn "(add 4 5) = %i" result

let add x y = x + y
let result1 = add 4 5
let result2 = add 6 7
let finalResult = add result1 result2

let add x y = x + y
let result =add (add 4 5) (add 6 7)

let cylinderVolume radius length : float =
   
   let pi = 3.14159
   length * pi * radius * radius

let sign num =
    if num > 0 then "positive"
    elif num < 0 then "negative"
    else "zero"

let replace(str: string) =
    str.Replace("A", "a")

let addu1 (x : uint32) y =
    x + y

let (|>) x f = f x

let result = 0.5 |> System.Math.Cos

let add x y = x + y
let result = add 6 7 |> add 4 |> add 5

let result = add 6 7 |> add 4

let sub (a, b) = a - b
let subFour = sub 4

prog.fs(15,19): error: FS0001: This expression has type
int
but is here used with type
'a * 'b

let rec fib x =
match x with
| 1 -> 1
| 2 -> 1
| x -> fib (x - 1) + fib (x - 2)


printfn "(fib 2) = %i" (fib 2)
printfn "(fib 6) = %i" (fib 6)
printfn "(fib 11) = %i" (fib 11) 

(fib 2) = 1
(fib 6) = 8
(fib 11) = 89

let rec Even x =
   if x = 0 then true 
   else Odd (x - 1)
and Odd x =
   if x = 1 then true 
   else Even (x - 1)

let firstFunction x = x + 1
let secondFunction x = x * 2
let newFunction = firstFunction >> secondFunction
let result = newFunction 100

let sumOfDivisors n =
    let rec loop current max acc =

//شروع تابع داخلی

   if current > max then
            acc
        else
            if n % current = 0 then
                loop (current + 1) max (acc + current)
            else
                loop (current + 1) max acc

//ادامه بدنه تابع اصلی

 let start = 2
    let max = n / 2     (* largest factor, apart from n, cannot be > n / 2 *)
    let minSum = 1 + n  (* 1 and n are already factors of n *)
    loop start max minSum
 
printfn "%d" (sumOfDivisors 10)

  if current > max then
            acc
        else
            if n % current = 0 then
                loop (current + 1) max (acc + current)
            else
                loop (current + 1) max acc

open System
open System.Windows.Forms

let form1 = new Form()
form1.Text <- "XYZ"

[<STAThread>]
do
   Application.Run(form1)

  <h1>News</h1>
  <div>Welcome to our site!</div>

  <h2>World</h2>

  <h3>Title 1</h3>
  <div>description 1.</div>

  <h2>Science</h2>

  <h3>Title 2</h3>
  <div>description 2.</div>

  var headings = document.querySelectorAll('h2, h3');
  for (var i = 0; i < headings.length; i++) {
    if (headings[i].tagName === 'H2') {
      headings[i].style.color = 'blue';
    }
    else {
      headings[i].style.color = 'green';
    }
  }

<h2 style="color: blue">….</h2>
<h3 style="color: green">….</h3>

  <h2>World</h2>

  ...

  <h2>Science</h2>

 <script>
  var headings = document.querySelectorAll('h2');
  for (var i = 0; i < headings.length; i++) {
    headings[i].style.color = 'blue';
    headings[i].style.fontWeight = 'bold';
  }
 </script>

 headings[i].style['font-weight'] = 'bold';

  var headings = document.querySelectorAll('h2');

  for (var i = 0; i < headings.length; i++) {
    headings[i].style.cssText = 'color: blue; font-weight: bold';
  }

h2 { color: blue; }
h3 { color: green; }

 <link href="styles.css" rel="style sheet">

<style>
  h2 { color: blue; }
  h3 { color: green; }
</style>

var sheet = document.styleSheets[0];
sheet.insertRule('h2 { font-style: italic; }', sheet.cssRules.length - 1);

// hide an element
$element.hide();

// show it again
$element.show();

element.setAttribute('hidden', '');

element.removeAttribute('hidden');

<style>
  .box {
    padding: 10px;
    margin: 5px;
    border: 3px solid;
    display: inline-block;
  }
</style>
<span class="box">a box</span>

 // returns 38
var clientHeight = document.querySelector('.box').clientHeight;

// returns 55
var clientWidth = document.querySelector('.box').clientWidth;

 // returns 44
var offsetHeight = document.querySelector('.box').offsetHeight;

// returns 61
var offsetWidth = document.querySelector('.box').offsetWidth;

facid: 9, Name: 'Spa', membercost: 20, guestcost: 30, initialoutlay: 100000, monthlymaintenance: 800.

insert into facilities
    (facid, name, membercost, guestcost, initialoutlay, monthlymaintenance)
    values (9, 'Spa', 20, 30, 100000, 800);
-- OR
insert into facilities values (9, 'Spa', 20, 30, 100000, 800);

context.Facilities.Add(new Facility
                {
                    Name = "Spa",
                    MemberCost = 20,
                    GuestCost = 30,
                    InitialOutlay = 100000,
                    MonthlyMaintenance = 800
                });
context.SaveChanges();

facid: 9, Name: 'Spa', membercost: 20, guestcost: 30, initialoutlay: 100000, monthlymaintenance: 800.
facid: 10, Name: 'Squash Court 2', membercost: 3.5, guestcost: 17.5, initialoutlay: 5000, monthlymaintenance: 80.

insert into facilities
    (facid, name, membercost, guestcost, initialoutlay, monthlymaintenance)
    values
        (9, 'Spa', 20, 30, 100000, 800),
        (10, 'Squash Court 2', 3.5, 17.5, 5000, 80);

context.Facilities.Add(new Facility
                {
                    Name = "Spa",
                    MemberCost = 20,
                    GuestCost = 30,
                    InitialOutlay = 100000,
                    MonthlyMaintenance = 800
                });

context.Facilities.Add(new Facility
                {
                    Name = "Squash Court 2",
                    MemberCost = 3.5M,
                    GuestCost = 17.5M,
                    InitialOutlay = 5000,
                    MonthlyMaintenance = 80
                });
context.SaveChanges();

Name: 'Spa', membercost: 20, guestcost: 30, initialoutlay: 100000, monthlymaintenance: 800.

namespace EFCorePgExercises.Entities
{
    public class FacilityConfiguration : IEntityTypeConfiguration<Facility>
    {
        public void Configure(EntityTypeBuilder<Facility> builder)
        {
            builder.HasKey(facility => facility.FacId);
            builder.Property(facility => facility.FacId).IsRequired().UseIdentityColumn(seed: 0, increment: 1);

CREATE TABLE [dbo].[Facilities](
[FacId] [int] IDENTITY(0,1) NOT NULL,
--- ...
 CONSTRAINT [PK_Facilities] PRIMARY KEY CLUSTERED 
(
[FacId] ASC
);

update facilities
    set initialoutlay = 10000
    where facid = 1;

var facility1 = context.Facilities.Find(1);
facility1.InitialOutlay = 10000;
context.SaveChanges();

update cd.facilities
    set
        membercost = 6,
        guestcost = 30
    where facid in (0,1);

int[] facIds = { 0, 1 };
var tennisCourts = context.Facilities.Where(x => facIds.Contains(x.FacId)).ToList();
foreach (var tennisCourt in tennisCourts)
{
     tennisCourt.MemberCost = 6;
     tennisCourt.GuestCost = 30;
}

context.SaveChanges();

update cd.facilities facs
    set
        membercost = (select membercost * 1.1 from cd.facilities where facid = 0),
        guestcost = (select guestcost * 1.1 from cd.facilities where facid = 0)
    where facs.facid = 1;

var fac0 = context.Facilities.Where(x => x.FacId == 0).First();
var fac1 = context.Facilities.Where(x => x.FacId == 1).First();
fac1.MemberCost = fac0.MemberCost * 1.1M;
fac1.GuestCost = fac0.GuestCost * 1.1M;

context.SaveChanges();

delete from bookings

context.Bookings.RemoveRange(context.Bookings.ToList());
context.SaveChanges();

delete from members where memid = 37;

var mem37 = context.Members.Where(x => x.MemId == 37).First();
context.Members.Remove(mem37);

context.SaveChanges();

var entry = context.Entry(new Member { MemId = 37 });
entry.State = EntityState.Deleted;
context.SaveChanges();

SET NOCOUNT ON;
DELETE FROM [Members]
WHERE [MemId] = @p0;
SELECT @@ROWCOUNT;

delete from members where memid not in (select memid from cd.bookings);

var mems = context.Members.Where(x =>
  !context.Bookings.Select(x => x.MemId).Contains(x.MemId)).ToList();
context.Members.RemoveRange(mems);

context.SaveChanges();

public class Product
{
    public int Id { get; set; }
    public string Name { get; set; }
    public decimal Price { get; set; }
    public string Category { get; set; }
}

namespace WebForms
{
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Net;
    using System.Net.Http;
    using System.Web.Http;

    public class ProductsController : ApiController
    {

        Product[] products = new Product[] 
        { 
            new Product { Id = 1, Name = "Tomato Soup", Category = "Groceries", Price = 1 }, 
            new Product { Id = 2, Name = "Yo-yo", Category = "Toys", Price = 3.75M }, 
            new Product { Id = 3, Name = "Hammer", Category = "Hardware", Price = 16.99M } 
        };

        public IEnumerable<Product> GetAllProducts()
        {
            return products;
        }

        public Product GetProductById(int id)
        {
            var product = products.FirstOrDefault((p) => p.Id == id);
            if (product == null)
            {
                throw new HttpResponseException(HttpStatusCode.NotFound);
            }
            return product;
        }

        public IEnumerable<Product> GetProductsByCategory(string category)
        {
            return products.Where(
                (p) => string.Equals(p.Category, category,
                    StringComparison.OrdinalIgnoreCase));
        }
    }
}

using System.Web.Http;

RouteTable.Routes.MapHttpRoute(
    name: "DefaultApi",
    routeTemplate: "api/{controller}/{id}",
    defaults: new { id = System.Web.Http.RouteParameter.Optional }
    );

<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.Master" 
    AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="WebForms._Default" %>

<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">
</asp:Content>

<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
    <h2>Products</h2>
    <table>
    <thead>
        <tr><th>Name</th><th>Price</th></tr>
    </thead>
    <tbody id="products">
    </tbody>
    </table>
</asp:Content>

<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">
    <script src="Scripts/jquery-1.7.1.min.js" type="text/javascript"></script>
</asp:Content>

<script type="text/javascript">
    function getProducts() {
        $.getJSON("api/products",
            function (data) {
                $('#products').empty(); // Clear the table body.

                // Loop through the list of products.
                $.each(data, function (key, val) {
                    // Add a table row for the product.
                    var row = '<td>' + val.Name + '</td><td>' + val.Price + '</td>';
                    $('<tr/>', { text: row })  // Append the name.
                        .appendTo($('#products'));
                });
            });
        }

        $(document).ready(getProducts);
</script>