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בדיקת יכולת ושימוש ב 2 טכניקות חדשות ב visual studio 2008 c# .net 3.5 vs 2008 לגישה וחיתוך נתונים בזמן ריצה: LINQ ו- AonymousDeligates בטיפול ב List Generic של נתוני אוביקטים של סטודנטים המכיל גם מערך ציונים לכל סטודנט, וList Generic של אנשי קשר לסטודנטים שמקושרים באמצעות ה id כולל מיון ראו הסבר מפורט יותר בתוכן המאמר..
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Xml;
using System.Xml.Serialization;
namespace AonymousDeligatesAndLINQ
{
public class AonymousDeligates
{
static void
{
AonymousDeligates an = new AonymousDeligates();
an.start();
// Keep the console window open in debug mode
System.Console.WriteLine("\n\nPress any key to exit.");
Console.Beep();
System.Console.ReadKey();
}
public AonymousDeligates() { }
public void start()
{
DAL dal = new DAL();//fill data
dal.Start();//Linq and AonymousDeligates
}
}
public class DAL
{
public DAL() { }
public void Start()
{
DAL app = new DAL();
//========1 AonymousDeligates.FindAll(T){} == Linq query ???
#region Linq
//start linq
// Produce a filtered sequence of unmodified Students.
IEnumerable<Student> studentQuery1 =
from student in app.students
where student.ID > 111
select student;
Console.WriteLine("Query1: select range_variable");
foreach (Student s in studentQuery1)
{
Console.WriteLine(s.ToString());
}
// Produce a filtered sequence of elements that contain
// only one property of each Student.
IEnumerable<String> studentQuery2 =
from student in app.students
where student.ID > 111
select student.Last;
Console.WriteLine("\r\n studentQuery2: select range_variable.Property");
foreach (string s in studentQuery2)
{
Console.WriteLine(s);
}
// Produce a filtered sequence of objects created by
// a method call on each Student.
IEnumerable<ContactInfo> studentQuery3 =
from student in app.students
where student.ID > 111
select student.GetContactInfo(app, student.ID);
Console.WriteLine("\r\n studentQuery3: select range_variable.Method");
foreach (ContactInfo ci in studentQuery3)
{
if (ci != null)
Console.WriteLine(ci.ToString());
}
// Produce a filtered sequence of ints from
// the internal array inside each Student.
IEnumerable<int> studentQuery4 =
from student in app.students
where student.ID > 111
select student.Scores[0];
Console.WriteLine("\r\n studentQuery4: select range_variable[index]");
foreach (int i in studentQuery4)
{
Console.WriteLine("First score = {0}", i);
}
// Produce a filtered sequence of doubles
// that are the result of an expression.
IEnumerable<double> studentQuery5 =
from student in app.students
where student.ID > 111
select student.Scores[0] * 1.1;
Console.WriteLine("\r\n studentQuery5: select expression");
foreach (double d in studentQuery5)
{
Console.WriteLine("Adjusted first score = {0}", d);
}
// Produce a filtered sequence of doubles that are
// the result of a method call.
IEnumerable<double> studentQuery6 =
from student in app.students
where student.ID > 111
select student.Scores.Average();
Console.WriteLine("\r\n studentQuery6: select expression2");
foreach (double d in studentQuery6)
{
Console.WriteLine("Average = {0}", d);
}
// Produce a filtered sequence of anonymous types
// that contain only two properties from each Student.
var studentQuery7 =
from student in app.students
where student.ID > 111
select new { student.First, student.Last };
Console.WriteLine("\r\n studentQuery7: select new anonymous type");
foreach (var item in studentQuery7)
{
Console.WriteLine("{0}, {1}", item.Last, item.First);
}
// Produce a filtered sequence of named objects that contain
// a method return value and a property from each Student.
// Use named types if you need to pass the query variable
// across a method boundary.
IEnumerable<ScoreInfo> studentQuery8 =
from student in app.students
where student.ID > 111
select new ScoreInfo
{
Average = student.Scores.Average(),
ID = student.ID
};
Console.WriteLine("\r\n studentQuery8: select new named type");
foreach (ScoreInfo si in studentQuery8)
{
Console.WriteLine("ID = {0}, Average = {1}", si.ID, si.Average);
}
// Produce a filtered sequence of students who appear on a contact list
// and whose average is greater than 85.
IEnumerable<ContactInfo> studentQuery9 =
from student in app.students
where student.Scores.Average() > 85
join ci in app.contactList on student.ID equals ci.ID
select ci;
Console.WriteLine("\r\n studentQuery9: select result of join clause");
foreach (ContactInfo ci in studentQuery9)
{
Console.WriteLine("ID = {0}, Email = {1}", ci.ID, ci.Email);
}
#endregion
#region anonymousDeligates
//start anonymousDeligates
List<Student> studentsBig =
app.students.FindAll(delegate(Student s)
{
return (s.ID > 111);
});
Console.WriteLine("Query1: select annonimus deligate range_variable");
foreach (Student s in studentsBig)
{
Console.WriteLine(s.ToString());
}
List<Student> lints =
app.students.FindAll(delegate(Student item)
{
return ((item.Scores[0] > 60 && item.ID > 111)
&& (item.Scores[1] > 60 && item.ID > 111)
&& (item.Scores[2] > 60 && item.ID > 111)
&& (item.Scores[3] > 60 && item.ID > 111)
);
});
app.students.ForEach(delegate(Student s)
{
if (s.ID > 111)
s.Scores[0] -= 1;
});
Student lastStu = app.students.FindLast(delegate(Student s)
{
return s.ID > 112;
}
);
Student firstStu = app.students.Find(delegate(Student s)
{
return s.ID < 120;
}
);
int firstStudentIndex = app.students.FindIndex(delegate(Student s)//first index in list==0
{ return s.ID > 100; });
int lastStudentIndex = app.students.FindLastIndex(delegate(Student s)//last index in list==3
{ return s.ID > 100; });
bool weHaveID112 = app.students.Exists(delegate(Student s)
{ return s.ID == 112; });
bool weHaveFirstNameSvetlana = app.students.Exists(delegate(Student s)
{ return s.First == "Svetlana"; });
bool true4AllSvetlana = app.students.TrueForAll(delegate(Student s)
{ return s.First == "Svetlana"; });
bool allStudentsHaveLastName =
app.students.TrueForAll(delegate(Student s)
{ return (!string.IsNullOrEmpty(s.Last)); });
app.students.ForEach(delegate(Student s)
{ s.ID += 10; });
app.students.Sort(new StudendtsSorter());//sort anonymous type
//end anonymousDeligates
#endregion
}
#region Define some classes
public class Student
{
public Student() { }
public Student(string First, string Last, int ID, List<int> T)
{
this.First = First;
this.Last = Last;
this.ID = ID;
this.Scores = T;
}
private string _first;
public string First { get { return _first; } set { _first = value; } }
private string _last;
public string Last { get { return _last; } set { _last = value; } }
private int _id;
public int ID { get { return _id; } set { _id = value; } }
public List<int> Scores;
public ContactInfo GetContactInfo(DAL app, int id)
{
ContactInfo cInfo =
(from ci in app.contactList
where ci.ID == id
select ci)
.FirstOrDefault();
return cInfo;
}
public override string ToString()
{
return First + " " + Last + ":" + ID;
}
}
/// <summary>
/// implement IComparer on List<Student> (for anonymousDelegate function Sort)
/// </summary>
class StudendtsSorter : Comparer<Student>
{
public override int Compare(Student x, Student y)
{
if (x.ID > y.ID)
return 1;
else if (y.ID > x.ID)
return -1;
else
return 0;
}
}
public class ContactInfo
{
public int ID { get; set; }
public string Email { get; set; }
public string Phone { get; set; }
public override string ToString() { return Email + "," + Phone; }
}
public class ScoreInfo
{
public double Average { get; set; }
public int ID { get; set; }
}
#endregion
#region The primary data source use in this program
public List<Student> students = new List<Student>()
{
new Student {First="Svetlana", Last="Omelchenko", ID=111, Scores= new List<int>() {97, 92, 81, 60}},
new Student {First="Claire", Last=
new Student {First="Sven", Last="Mortensen", ID=113, Scores= new List<int>() {88, 94, 65, 91}},
new Student {First="Cesar", Last=
};
List<ContactInfo> contactList = new List<ContactInfo>()
{
new ContactInfo {ID=111, Email="SvetlanO@Contoso.com", Phone="206-555-0108"},
new ContactInfo {ID=112, Email="ClaireO@Contoso.com", Phone="206-555-0298"},
new ContactInfo {ID=113, Email="SvenMort@Contoso.com", Phone="206-555-1130"},
new ContactInfo {ID=114, Email="CesarGar@Contoso.com", Phone="206-555-0521"}
};
#endregion
}
}