ASP.NET 3.5 Training Course Notes(1)

1. this.Request.QueryString[null]
this.Request.QueryString["varName"] - - ?varName=...

2.You need manually input event handler Page_Init( object sender , EventArgs e) ;

3.Page Event order
PreInit() -> Page_Init() ->Page_PreLoad() -> Page_Load() -> Page_Unload()

.Net Framework Application Development Foundation(3)--Sample

1. Graphics sample
WinForm Sample: ( ColorDialog Control , fontDialog Constrol used)

public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

Pen aPen = new Pen(Color.Navy, 3);
private int? lastX = null;
private int? lastY = null;
// store last line drawn
private class myPath
{
public Pen newPen;
public float lastX, lastY, currentX, CurrentY;
}
List paths = new List();

private void Form1_MouseMove(object sender, MouseEventArgs e)
{
var g = this.CreateGraphics();
g.SmoothingMode = SmoothingMode.HighQuality;

if (e.Button == MouseButtons.Left)
{
if (lastX.HasValue && lastY.HasValue)
{
g.DrawLine(aPen, (float) lastX, (float) lastY, e.X, e.Y);
paths.Add(new myPath()
{
newPen = aPen,
currentX = e.X,
CurrentY = e.Y,
lastX = (float) lastX,
lastY = (float) lastY
});
}
else
{
g.DrawRectangle(aPen, e.X, e.Y, 1, 1);
}
lastX = e.X;
lastY = e.Y;
}
else
{
lastX = null;
lastY = null;
}
}

private void Form1_Paint(object sender, PaintEventArgs e)
{
var g = this.CreateGraphics();
g.SmoothingMode = SmoothingMode.HighQuality;
// when clear the graphics , keep the color white
this.BackColor = Color.White;
foreach (var s in paths)
{
g.DrawLine(s.newPen , s.lastX , s.lastY , s.currentX,s.CurrentY);
}
}

private void Form1_MouseClick(object sender, MouseEventArgs e)
{
var g = this.CreateGraphics();
if( e.Button == System.Windows.Forms.MouseButtons.Right)
{
g.Clear(Color.White);
paths.Clear();
}
}

private void button1_Click(object sender, EventArgs e)
{
if(colorDialog1.ShowDialog(this) == DialogResult.OK)
{
aPen = new Pen(colorDialog1.Color);
button1.BackColor = colorDialog1.Color;
}
}

private void numericUpDown1_ValueChanged(object sender, EventArgs e)
{
aPen = new Pen(aPen.Color, (float)numericUpDown1.Value);
}

private void button2_Click(object sender, EventArgs e)
{
var g = this.CreateGraphics();

Font font;

if( fontDialog1.ShowDialog() == DialogResult.OK)
{
font = fontDialog1.Font;
}
else
{
font = new Font("Arial" , 60 , FontStyle.Bold | FontStyle.Underline);
}

g.DrawString(textBox1.Text ,font ,Brushes.Navy , 100f , 100f);
}

}

2. Multiple threading programming
class Program
{
static void Main(string[] args)
{
//utilize the automatical threading method
ThreadPool.QueueUserWorkItem(DemoThreading.Proc);
ThreadPool.QueueUserWorkItem(DemoThreading.ProcWithArgument, 5);

Thread.Sleep(2000);// have backgroud thread finished first
int anum, cnum;
ThreadPool.GetMaxThreads(out anum , out cnum);
;
Console.WriteLine("The Main thread exist. The threadPool has {0} threads availabe. {1} completionPortThreads.",
anum , cnum);
}
}

public class DemoThreading
{
//show how many days from 2000 to 2010
public static void Proc(object input) //input is uesless only to meet the satisfaction of signature
{
DateTime oldTime = new DateTime(2000, 1 , 1);
DateTime newTime = new DateTime(2010 , 1 , 1);
TimeSpan ts = newTime - oldTime;

Console.WriteLine("There are total {0} days from 2000 to 2010" , ts.TotalDays);

}
//return the factorial of a
public static void ProcWithArgument( object input )
{
int a = Convert.ToInt32(input);
int fab = 1;

if (a == 1)
fab = 1;
else
{
checked
{
int i;
for (i = 1; i <= a; i++) { fab = fab * i; } } } Console.WriteLine("The factorial of number {0} is {1} .", a , fab); } }

2.2 managing threads
class Program
{
static void Main(string[] args)
{
//managing threads methods
var thread = new Thread(new ParameterizedThreadStart(DemoThreading.Proc));
var another = new Thread(new ParameterizedThreadStart(DemoThreading.ProcWithArgument));

another.Priority = ThreadPriority.Highest;
thread.Priority = ThreadPriority.BelowNormal;
thread.Start();
another.Start(5);

Thread.Sleep(2000);
Console.WriteLine("The main thread is ending.");
}
}

public class DemoThreading
{
//show how many days from 2000 to 2010
public static void Proc(object input) //input is uesless only to meet the satisfaction of signature
{
DateTime oldTime = new DateTime(2000, 1 , 1);
DateTime newTime = new DateTime(2010 , 1 , 1);
TimeSpan ts = newTime - oldTime;

Console.WriteLine("There are total {0} days from 2000 to 2010" , ts.TotalDays);

}
//return the factorial of a
public static void ProcWithArgument( object input )
{
int a = Convert.ToInt32(input);
int fab = 1;

if (a == 1)
fab = 1;
else
{
checked
{
int i;
for (i = 1; i <= a; i++)
{
fab = fab * i;
}
}
}

Console.WriteLine("The factorial of number {0} is {1} .", a , fab);
}

private string _file = "Hello";//private field
private ReaderWriterLock rwl = new ReaderWriterLock();//syn lock

public void WriteFile()
{
lock (_file)
{
_file += " It's good.";
}

}

public void ReadFile()
{
rwl.AcquireReaderLock(10000);
for( int i=1; i<=3 ; i++)
{
Console.WriteLine(_file);
Thread.Sleep(1000);
}
rwl.ReleaseReaderLock();
}
}

.Net Framework Application Development Foundation(2)--Samples

1. FileSystemWatcher Sample:
class Program
{
static void Main(string[] args)
{
FileSystemWatcher fsw = new FileSystemWatcher(@"d:\");


fsw.NotifyFilter = NotifyFilters.FileName | NotifyFilters.DirectoryName | NotifyFilters.CreationTime;
fsw.IncludeSubdirectories = true;

fsw.Created += new FileSystemEventHandler(fsw_SthHappened);
fsw.Deleted += new FileSystemEventHandler(fsw_SthHappened);
fsw.Renamed += new RenamedEventHandler(fsw_Renamed);
fsw.EnableRaisingEvents = true;
while( true )
{
Thread.Sleep(100);
}
}

static void fsw_Renamed(object sender, RenamedEventArgs e)
{
Console.WriteLine(e.Name + " => "+ e.ChangeType + " => " + e.OldName + " => " + e.FullPath + " -- " + DateTime.Now.ToLongTimeString());
}

static void fsw_SthHappened(object sender, FileSystemEventArgs e)
{
Console.WriteLine(e.Name + "=> "+ e.ChangeType + " => " + e.FullPath + " -- " + DateTime.Now.ToLongTimeString());
}
}

2. Serialization
using System;
using System.Collections.Specialized;
using System.Diagnostics;
using System.IO.Compression;
using System.IO.IsolatedStorage;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;
using System.Runtime.Serialization.Formatters.Soap;
using System.Security.Permissions;
using System.Text;
using System.Reflection;
using System.IO;
using System.Text.RegularExpressions;
using System.Threading;
using System.Xml.Serialization;

namespace ExplainNotes4
{
class Program
{
static void Main(string[] args)
{
//FileStream fs = new FileStream(@"d:\home\serializeDate.data", FileMode.Create, FileAccess.Write);
//Invoice aTax = new Invoice() {ItemName = "For DIY", ReleaseDate = DateTime.Now, Number = 100, Price = 12.8M};
//aTax.SetTotal();
//BinaryFormatter bf = new BinaryFormatter();
//bf.Serialize( fs , aTax);
//fs.Close();
//**************************************** using soapFormatter ****************
//FileStream fs = new FileStream(@"d:\home\serializeDate.xml", FileMode.Create, FileAccess.Write);
//Invoice aTax = new Invoice() { ItemName = "For DIY", ReleaseDate = DateTime.Now, Number = 100, Price = 12.8M };
//aTax.SetTotal();
//SoapFormatter sf = new SoapFormatter();
//sf.Serialize(fs, aTax);
//fs.Close();

//FileStream fs = new FileStream(@"d:\home\serializeDate.data", FileMode.Open , FileAccess.Read);
//Invoice another = new Invoice();
//BinaryFormatter bf = new BinaryFormatter();
//another = (Invoice) bf.Deserialize(fs);
//fs.Close();

//Console.WriteLine(another.Total);
FileStream fs = new FileStream(@"d:\home\serializeDate.xml", FileMode.Create, FileAccess.Write);
Invoice aTax = new Invoice() { ItemName = "For DIY", ReleaseDate = DateTime.Now, Number = 100, Price = 12.8M };
aTax.SetTotal();
XmlSerializer xs = new XmlSerializer(typeof(Invoice));
xs.Serialize(fs, aTax);
fs.Close();
}
}

[Serializable]
class Invoice : IDeserializationCallback
{
public string ItemName { set; get; }
public DateTime ReleaseDate { set; get; }
public int Number { set; get; }
public decimal Price { set; get; }

public decimal Total { get; private set; }

public void Sumary()
{ Console.WriteLine("this is an invoice.");}

public void SetTotal()
{
if (Price != 0 && Number != 0)
Total = Price*Number;
else
{
throw new NotSupportedException();
}
}

public void OnDeserialization(object sender)
{
Console.WriteLine("i make it");
}
public Invoice(){}
}

}

.Net Framework Application Development Foundation(2)

Code Explanation of C# Languege:

1. object (base method )
class Program
{
static void Main(string[] args)
{
// any object class includes 4 methods : Equals() ,ToString() ,GetType() , GetHashCode() ;
Student aStud = new Student(){ Age = 20, Name = "Jim Parson",Subject = "History"};
Student bStud = new Student() { Age = 20, Name = "Jim Parson", Subject = "History" };

Console.WriteLine(aStud.GetType());// reflection base method
Console.WriteLine(aStud.Equals(bStud));
Console.WriteLine(aStud == bStud);
Console.WriteLine( aStud.GetHashCode());
aStud.Age = 25;
aStud.Name = "tom";
aStud.Subject = "English";
Console.WriteLine(aStud.GetHashCode());
Console.WriteLine(bStud.GetHashCode());
Console.WriteLine(aStud.ToString());
return;
}

class Student
{
// automatical property
public string Name { set; get; }
public int Age { set; get; }
public string Subject { set; get; }

public override bool Equals(object obj)
{
if (obj == null)
throw new ArgumentNullException("obj");

var other = obj as Student;// obj should be Student class object
return (other != null && other.Age == Age && other.Name == Name && other.Subject == Subject);
}

public override int GetHashCode()
{
return (Name +":" + Age +":"+ Subject).GetHashCode();
}

public static bool operator ==( Student a , Student b)
{
if( ReferenceEquals(a,b))// Object.ReferenceEquals( a , b)
return true;

if ((object)a == null || (object)b == null)
return false;

return a.Equals((b));

}

public static bool operator !=(Student a, Student b)
{
return !(a == b);
}

public override string ToString()
{
return Name + " : " + Age + " : " + Subject;
}
}

2. var keyword ( I love using it)
//*** C# support double type number reminder ***
//Console.WriteLine(7.2%2.4);
//return;

//*** C# Definite Assignement Rule ***
// int aNum;
//Console.WriteLine(aNum);
// or using out keyword
//var afloat = 12f;
//var adouble = 24.5;
//var money = 21.35m;
//Console.WriteLine("{0} {1} {2} {3} {4}" , num , str, afloat,adouble,money);

//Console.WriteLine( "this is a nice day." + "that is right.");
//string input = Console.ReadLine();
//int another;
//if( int.TryParse( input, out another ))
// Console.WriteLine(another);
// int aNum = int.Parse(input);

//*** C# is case-sensitive language ***
//int integer = 100, integEr = 200;
//Console.WriteLine( "{0} -- {1}" , integer , integEr)

3. List , Array , Lambda ,ForEach()
// list has ForEach() , linq to object always uses list
int[] arr = {10, 40, 43, 55, 67, 35, 6, 78, 9};
var alist = arr.ToList();
alist.ForEach(Console.WriteLine);// == alist.ForEach( item=>Console.WriteLine(item));

4.Switch Statement

string input = Console.ReadLine();
switch (input) // input could int type , char or string , no float , double
{
case "1" :
Console.WriteLine("input is 1");
break;
case "2": // can fall-through
case "3":
Console.WriteLine("input is 2 or 3");
break;
case "4":
Console.WriteLine("input is 4");
break;
default :
Console.WriteLine("default input");
break;
}
4. Overflow Exception : checked and unchecked
int n = int.MaxValue;
try
{
checked // or unchecked
{
n += 1;
Console.WriteLine("overflow?");

}
}
catch (OverflowException e)
{
Console.WriteLine("overflow found");
}

byte test = 240;
byte another = 120;
test = unchecked((byte)(test + another));
Console.WriteLine(test);
test = 240;
test = checked((byte)(test+ another) );

5. Class Student -- Constructors
///

/// all kinds of constuctors
///

///
///
///
public Student( string _name , int _age , string _sub)
{
Name = _name;
Age = _age;
Subject = _sub;
}
public Student( string _name , int _age):this(_name ,_age , "N/A")
{

}

public Student( string _name):this(_name , 18)
{
}

public Student( int age):this("noName" , age )
{
}
public Student():this("unknown")
{
}

6. Const and Readonly (the same use but readonly type can be used in run time
class Media
{
public const int Month = 12;
// error => public const DateTime Current = DateTime.Now.Year;
public readonly DateTime Current = DateTime.Now;
}

7. Static Class in C#
public static class Shape
{
public static int Area { set; get; } //property

private static int _field; // field

public static void Show()
{
throw new NotImplementedException();
}
}

8.Anonymous Class
var anonymousClass = new {Name = "Tom", Age = 20};
Console.WriteLine(anonymousClass);
or
string atr = "this is a good movie." ;
var other = atr.split( new [] { " "}) ;
or In Linq Application

9. Nullable and Nullable<T> 　－－we always use generics one
Nullable<int> num = null; // or int? num = null or Enumeration Type
num = 100;
if(num.HasValue)
Console.WriteLine(num);
Console.WriteLine(num.GetType());

10. Boxing and unboxing
int one = 100;
object other = one; // boxing
one = (int) other; // unboxing
Console.WriteLine(one);

11. Is and As Operator ( in Type Cast )
Student aStud = new Student(){ Age = 20, Name = "Jim Parson",Subject = "History"};
object obj2 = aStud; //
var other2 = obj2 as Student;//
if( other2 != null )//
Console.WriteLine("it is Student Type");//
return;
or
Student aStud = new Student(){ Age = 20, Name = "Jim Parson",Subject = "History"};
object obj = aStud;
var other = obj;
if( other is Student)
Console.WriteLine("yes");

12.Enumeration
enum Days :byte { Sat = 1, Sun, Mon, Tue, Wed, Thu, Fri }; // not be defined in a method

13. Array copy
int[] arr = {5, 9, 2, 4, 8};
var another = (int[]) arr.Clone();
//var another = new int[arr.Length];
//Array.Copy(arr, another, arr.Length);
//arr.CopyTo(another , 0);
another.ToList().ForEach(Console.WriteLine);

14. extension method
static class MyClass
{
public static int IntegerPart( this double a)
{
return Convert.ToInt32(a);
}
}
class Program
{　　
　　static void Main(string[] args)
{
double num = 6.5;
Console.WriteLine(num.IntegerPart());
　　　return ;
}
}

15. Interface ( explicitly and implicitly)
internal interface ITalk
{
void Talk();
bool WantToTalk();
}

internal interface ISpeak
{
void Speak();
bool WantToTalk();
}

internal class AClass : ITalk , ISpeak
{
public void Talk()
{
Console.WriteLine("method Talk called");
}
bool ITalk.WantToTalk()
{
Console.WriteLine("method ITalk.WantToTalk called");
return true;
}
bool ISpeak.WantToTalk()
{
Console.WriteLine("method ISpeak.WantToTalk called");
return false;
}
public virtual void Speak()
{
Console.WriteLine("method speak called");
}

public void PrintAll()
{
Console.WriteLine("All Information.");
}
}

class Program
{
static void Main(string[] args)
{
AClass anotherOne = new AClass();

anotherOne.Speak();// object cannot call explicitly interface methods
anotherOne.Talk();

ITalk anInter = anotherOne; // the interface variable can only call its own methods
anInter.Talk();
anInter.WantToTalk();

ISpeak anInter2 = anotherOne;
anInter2.Speak();
anInter2.WantToTalk();
}}

16. Abstract Class
class Library where T : Media
{
public List Items { get; set; }
}

abstract class Media
{
public string ISBN { get; set; }
}

class Book : Media
{
}

class Dvd : Media
{
}

17. Property
public class InterClass
{
public string Name { set; get; }
public int ID { get; private set; } //read only property
public string Score { set; private get; } // write only
}
static void Main(string[] args)
{
InterClass anotherOne = new InterClass() { Name = "Tom", Score = "30"};
}

18.Generic Class
class Media
{
public string ISDN { set; get; }
}
class Book:Media{}
class DVD : Media{}
class Library<T> where T:Media
{
public List<T> Item { get; set; }
}

19. LINQ to Objects
var addresses = new[]
{
new {CompanyName = "ASK", City = "Tokyo", Country = "Japan"},
new {CompanyName = "TPG", City = "Sydney", Country = "Australia"},
new {CompanyName = "Nissan", City = "Osaka", Country = "Japan"},
new {CompanyName = "Toshiba", City = "Tokyo", Country = "Japan"},
new {CompanyName = "ALG", City = "New York", Country = "USA"}
};

var customers = new [] // anonymous array
{
new { CID = 1,FName = "Tim", SName = "Anderson", Age = 23 , CompanyName="ASK"},
new { CID =2,FName = "Loly", SName = "Green", Age = 22,CompanyName="TPG"},
new{ CID =3,FName = "Tom" ,SName="Lee" , Age=21 ,CompanyName="ALG"} ,
new{ CID =4,FName = "Bob" ,SName="Camp" , Age=23,CompanyName="Toshiba"} ,
new{ CID =5 ,FName = "Jason" ,SName="Troops" , Age=24,CompanyName="ALG"} ,
};// like a table

//var firstnames = customers.Select(name => name.FName + " " + name.SName +"--"+ name.Age);//Select statement
var firstnames = from name in customers select new {name.FName, name.SName, name.Age};
//var fullItems = customers.Select(item => new {FullName = item.FName + " " + item.SName, Age = item.Age});
//var filter = customers.Where(age => int.Equals(age.Age, 23)).Select(aname => aname.FName);//where statement
var filter = from age in customers where int.Equals(age.Age, 23) select age.FName;
//var orderBy = customers.OrderByDescending(order=>order.Age).Select(aname => aname.FName);//order by statement
var orderBy = from order in customers orderby order.Age descending select order.FName;
//var joins = customers.Select(c => new {c.FName, c.SName, c.CompanyName}).Join(addresses,
// cust => cust.CompanyName,
// addr => addr.CompanyName,
// (cust, addr) =>
// new
// {
// cust.FName,
// cust.SName,
// addr.City
// });
var joins = from c in customers
join a in addresses on c.CompanyName equals a.CompanyName
select new {c.FName, c.SName, a.City};
foreach (var item in firstnames)
{
Console.WriteLine(item);
}
Console.WriteLine();
//foreach (var item in fullItems)
//{
// Console.WriteLine(item);
//}
Console.WriteLine();
foreach (var e in filter)
{
Console.WriteLine(e);
}
Console.WriteLine();
foreach (var o in orderBy)
{
Console.WriteLine(o);
}
Console.WriteLine();
Console.WriteLine(customers.Select(cust => cust.Age).Distinct().Count());
foreach (var j in joins)
{
Console.WriteLine(j);
} }

20.IEnumerable , IEnumerator and yield statement
class Program
{
static void Main(string[] args)
{
AClass app = new AClass();

foreach (var @class in app.ShowMe())
{
Console.WriteLine(@class);
}

var iterator = app.GetEnumerator();
while( iterator.MoveNext())
{
Console.WriteLine(iterator.Current);
}
// iterator.Reset();reset method not implemented
return;

}
}

class AClass
{
private int[] arrInt = {1, 2, 3, 4, 5, 6, 7, 8, 9};
public IEnumerator GetEnumerator()
{
foreach (var i in arrInt)
{
if( i == 6)
yield break;

yield return i;
}
}
public IEnumerable ShowMe()
{
foreach (var i in arrInt)
{
yield return i;
}
}
}

21.delegate , Event , covariance and contravariance
class Program
{
public static void Show()
{
Console.WriteLine("show something to me.");
}
public static void Handler( object sender , EventArgs args)// subscriber
{
Console.WriteLine("yes , I subscribed this event.");
}

static void Main(string[] args)
{
BClass another = new BClass() {Name = "James", SCode = 939483};
BClass.AHandler del = another.PrintName;
del += another.PrintSCode;
del += Show;

//del();
del -= another.PrintName;//remove a delegation
del += another.PrintName;//add it again
del.Invoke();

Console.WriteLine( );
foreach (var s in del.GetInvocationList())
{
Console.WriteLine(s.Method.Name);
}
del = null;

another.MyEvent += Handler;
another.AMethod();//invoke event

}
}

class BClass
{
public delegate void AHandler();
// define an event
public event EventHandler MyEvent;

public string Name { set; get; }
public int SCode { set; get; }

public void PrintName()
{
Console.WriteLine(this.Name);
}
public void PrintSCode()
{
Console.WriteLine(this.SCode);
}
// invoke an event
public void AMethod()
{
if (this.MyEvent != null)
MyEvent(null, null);
}
}

.Net Framework Application Development Foundation(1)

Week One Notes:

Date: 7 /Feb/ 2009

About .Net Framework software: 3.5 SP1 , Visual Studio 2008 SP1 , an optimized tool for VS 2008-> VS Resharper ;

Free download student edition VS 2008 Pro Edition :

https://www.dreamspark.com/Products/Product.aspx?ProductId=1

Reference Books:

1. Pro C# 2008 and the .NET 3.5 Platform, Fourth Edition ( Apress)

2. MCTS Self-Paced Training Kit (Exam 70-536): Microsoft® .NET Framework Application

Development Foundation, Second edition ( Microsoft Press)

Notes:

1. About .NET:

.NET is their foundation for future application developments. ‘.NET’ is a set of technologies that are aimed at enabling development over the internet as well as aimed at enabling devices to be connected together via a common platform (.NET). This includes Mobile devices, personal computers and other electronic devices.

DLL Hell -- no more in .Net( versioning issues) via version forwarding

Security -- more secure in .Net ( by using managed code)

2. About VC++ and J++ , VB

VC++ -- there are too many compatibility issue( driver issue)

VJ++ -- rarely used ( not popular)

VB -- too basic

3. About .Net Versions

.Net 1.0 no more use ( using CLR 1.0)

.Net 1.1 still works and widely used in legacy applications ( shipped with Windows

Server 2003 and Visual Studio 2003 , using CLR 1.0 )

.Net 2.0 popular and shipped with visual studio 2005 and Windows Server 2003 R2 , SQL

Server 2005 ; full 64bit support; using CLR 2.0

.Net 3.0 better integrated in Vista and server 2008 ; still using CLR 2.0 ; new components:

WCF , WPF , WFF , WCardspace( bad , rarely used)

.Net 3.5 came withVisual Studio 2008 . Shipped with Server 2008 R2 and Windows 7;

still using CLR 2.0 ; Linq included .

.Net 4.0 coming with Visual Studio 2010 ( still in Beta)

So, .Net 2.0 includes WinForms , Web Service and ASP.Net

.Net 3.0 includes .net 2.0 and WFF , WPF , WCF and CardSpace

.Net3.5 includes .net 3.0 and LINQ , AJAX and REST( rarely used , some web service)

4. Common Type System(C#)

Actually , some types are never used in production environment:

uint , ulong , ushort , float

Always using : byte , int , long , bool and double

5. Constant and read only variable

Const in C# : the value must be assigned in source code.

E.G. const int a = DateTime.Today.Year ; ( Error) the right side is a variable actually

Use keyword readonly if value can only be assigned at runtime ; can be set only once. After that, it behaves as a constant

6. Types

value types ( value type , enumeration and structure type ) -- object types( class and interface , array)

Each of the numerical types map to a corresponding structure in the System namespace. Structures are “value types” allocated on the stack.

String and object are “reference types,” meaning the variable is allocated on the managed heap (garbage-collected).

Value types can be allocated into memory very quickly and have a very

fixed and predictable lifetime.

7. Indexer ( extension method , properties)

public MyType this [int index]

{

set{} ; get{} ;

}

8. Practice:

a. decimal money = 12.45m ;

cw( money.toString("c")) or cw( "{0:c}" , money); -- 'C' means format currency

b. int.MinValue , int.MaxValue , ....

c. char input = (char) Console.Read() ; -- default int type returned

d. Utilities method : char.isDigit() , isLetter() , isLower() , isUpper() ;

e. type convert or cast

string str = 12 ; int num ; if( int.TryParse(str , out num)) ...

d. Checked keyword -- only check overflow exception

e. Nullable a = null or int? a = null ; a.HasValue , a.Value.ToString()

a ?? -1 if a is null , return -1 when a is int type or return a.Value

equals a.HasValue ? a.Value.ToString() : "N/A"

f. var type is good utility.

g. string , str.Split( new []{','} ) ; array.toList() and then we can use foreach with iterator

h. Linq to object is good . ( toList , select, lambda expression)

9.Debugging

Stopwatch class ; sw.Start() , Stop() , sw.Elapsed ; return execution duration ;

10 . DateTime and TimeSpan are of value types and structures defined by system.

=============================================================

Some Code

==============================================================

class Program
{
static void Main(string[] args)
{
///
/// Excercise one
/// About DateTime and TimeSpan structures ( value types)
/// ITIC Training Course -- Week One
/// Trainee : Tonny Yan
/// Instructor: Bing Xie
/// Date: 10/02/2010
///

DateTime birth = DateTime.Now;
TimeSpan interval = new TimeSpan();
TimeSpan interval2 = new TimeSpan(2, 14, 28); // using values explicitly

Console.WriteLine(interval.Equals(TimeSpan.Zero));// true
Console.WriteLine(TimeSpan.MinValue);
Console.WriteLine(TimeSpan.MaxValue);
Console.WriteLine(interval2.ToString());

// duration of a trip
// the order is year , month , day , hour , min and second ;
DateTime departure = new DateTime(2010, 6, 12, 18, 32, 0);
DateTime arrival = new DateTime(2010, 6, 13, 22, 47, 0);
TimeSpan travelTime = arrival - departure;
Console.WriteLine("{0} - {1} = {2}", arrival, departure, travelTime);

// excercise for Property of a class
Student aSt = new Student("tonny", "Yan");
Console.WriteLine(aSt.ToString());

}
}

// define a class with auto-implemented properties
public class Student
{
public string Fullname { get; private set; }// readonly
public string Firstname { private get; set; }// write only
public string Lastname { private get; set; }

public Student(string firstname, string lastname)
{
this.Firstname = firstname;
this.Lastname = lastname;
this.Fullname = firstname + " " + lastname;
}

public override string ToString()
{
return Fullname;
}

}

SQL Server 2008 Implementation and Maintenance (3)

Schema , Table , View and Index

1.exec sp_spaceused 'tableName' -- show the disk space which data occupied

2. rename

sp_rename 'oldTableName' , 'NewTableName' ;

3. view all indexes

select * from sys.indexes ;

4. sp_who -- view all user session

SQL Server 2008 Implementation and Maintenance (2)

SQL SERVER 2008 T-SQL Management Commands(system procedures)

1. sp_help -- show all sys proc names , object type , owner name ...

2.select name from sys.databases ; -- show all databases in one instance

3.sp_helpdb 'database name' ; -- show the information and properties of a database

4.sp_dboption ; -- settable database options == alter database clause

5. function DB_Id("database Name") -- return database ID

6. Fulltext Search

select * from sys.fulltext_languages -- show the languages which are supported

select * from sys.fulltext_document_types -- show document format supported

7. Security

select * from sys.fn_builtin_permissions(default) ; ( view all permissions which can be granted for objects)

e.g. select * from sys.fn_builtin_permissions('login') (or ' database' )

select has_perms_by_name( 'databasename' , 'database ' , 'any' ) ; -- to view if the current user is granted any permission of using database )

execute as user='someone'

go

select has_perms_by_name('databaseName' ,'database' , 'any') ;

go

( check user someone has permissions )