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Language INtegrated Query
Before “Hello LINQ , ”!
There is “Why LINQ ”!?
WHYLINQ
?!
HELLO
LINQ!
Var Keyword
Extension Methods
Lambda Expression
LINQBASIC
S
var text = "Hello LINQ!“ ;
System.Collections.Generic.IEnumerable<bool>
class Full_of_Errors { var s = 9; public var MyMethod() { } public void MyMethod2(var t) { } }
VAR
KEYWORD
public static class StringExtensions { public static int ConvertToInt(this string number)
{ return Int32.Parse(number); }
public static string HammooD(this fl oat number){
return number.ToString(); } }
EXTENSIONMETHODS
string[] names = new string[] { "Hammod", "Tarek", "Alyan", "Nawwar" } ;
var name = names.Select(s => s.StartsWith("A"));
LAMBDA EXPRESSION
int[] fi bNum = { 1, 1, 2, 3, 5, 8, 13, 21, 34 };
double averageValue = fi bNum.Where(num => num % 2 == 1).Average();
SIMPLE EXAMPLES
var result = from b in Books where b.Price > 50.00
select b;
foreach (Book book in result){ Console.WriteLine(book.name)
}
SIMPLE EXAMPLES
int[] numbers = new int[7] { 0, 1, 2, 3, 4, 5, 6 };
var numQuery = from num in numbers where (num % 2) == 0
select num ;
foreach (int num in numQuery){ Console.Write("{0} ", num);
}
SIMPLE EXAMPLES
SIMPLE EXAMPLES
First()FirstOrDefault()Single()SingleOrDefault()All()Any()Sum()Contains()……
SIMPLE EXAMPLES
int[] numbers = new int[7] { 0, 1, 2, 3, 4, 5, 6 };
var numQuery = (from num in numbers where (num % 9) == 0 select num); if (numQuery.Any())
{ foreach (int num in numQuery)
{ Console.Write("{0} ", num);
}}
//more ideas?
<?xml version="1.0"?><BookParticipants> <BookParticipant type="Author"> <FirstName>Joe</FirstName> <LastName>Rattz</LastName> </BookParticipant> <BookParticipant type="Editor"> <FirstName>Ewan</FirstName> <LastName>Buckingham</LastName> </BookParticipant></BookParticipants>
LINQ TO XML – SIMPLE FILE
Xm lE l em ent x m l BookPa r t i c i pan t; Xm lAt t r i bu te x m lPa r t i c i pan tTy pe;
Xm lE l em ent x m l Fi r s tNam e; Xm lE l em ent x m l Las tName;
Xm lDocum en t x m l Doc = new Xm lDocum ent; ) ( Xm lE l em ent x m l BookPa r t i c i pan t s = x m lDoc .C rea teE lement ( " BookPa r t i c i pan t s " );
x m lDoc .Appen dCh i l d (x m lBookPa r t i c i pan t s ); x m lBookPar t i c i pan t = x m lDoc .C rea teE l em ent ( " BookPar t i c i pan t " );
x m lPa r t i c i pan tTy pe = x m lDoc .C rea teAt t r i bu te ( " t y pe" ); x m lPa r t i c i pan tTy pe . In nerTex t = " Au tho r; "
x m lBookPar t i c i pan t .A t t r i bu tes .Append (x m lPa r t i c i pan tTy pe); x m lFi r s tName = x m l Doc .C rea teE lem en t ( " Fi r s tName" );
x m lFi r s tName. Inne rTex t = " J oe; " x m lBookPar t i c i pan t .AppendCh i l d (x m l Fi r s tNam e);
x m lL as tNam e = x m lDoc .C rea teE lement ( " L as tName" ); x m lL as tNam e. Inn erTex t = " Ra t t z; "
x m lBookPar t i c i pan t .AppendCh i l d (x m l L as tName); x m lBookPar t i c i pan ts .Appen dCh i l d (x m lBookPa r t i c i pan t );
x m lBookPar t i c i pan t = x m lDoc .C rea teE l em ent ( " BookPar t i c i pan t " ); x m lPa r t i c i pan tTy pe = x m lDoc .C rea teAt t r i bu te ( " t y pe" );
x m lPa r t i c i pan tTy pe . In nerTex t = " Ed i to r; " x m lBookPar t i c i pan t .A t t r i bu tes .Append (x m lPa r t i c i pan tTy pe);
x m lFi r s tName = x m l Doc .C rea teE lem en t ( " Fi r s tName" ); x m lFi r s tName. Inne rTex t = "E wan; "
x m lBookPar t i c i pan t .AppendCh i l d (x m l Fi r s tNam e); x m lL as tNam e = x m lDoc .C rea teE lement ( " L as tName" );
x m lL as tNam e. Inn erTex t = " Buck ingham; " x m lBookPar t i c i pan t .AppendCh i l d (x m l L as tName);
x m lBookPar t i c i pan ts .Appen dCh i l d (x m lBookPa r t i c i pan t );
LINQ TO XML – DOM SYNTAX
var xBookParticipants = new XElement("BookParticipants", new XElement("BookParticipant", new XAttribute("type", "Author"), new XElement("FirstName", "Joe"), new XElement("LastName", "Rattz")), new XElement("BookParticipant", new XAttribute("type", "Editor"), new XElement("FirstName", "Ewan"), new XElement("LastName", "Buckingham")));
LINQ TO XML – BUILDING AN ELEMENT
doc.Save(@"E:\fi le.xml");
doc.Save(@"E:\fi le.xml",SaveOptions.DisableFormatting);
XDocument xmlDoc1 = XDocument.Load("TestFile.xml");
XElement name = new XElement("Author", "Hammod"); Console.WriteLine(name.Value);
LINQ TO XML - METHODS
string[] names = { "M.Hammod", "Golden Man", "Mohammed_807", "Nawwar" };
XElement OurGroupMembers = new XElement("OurGroup", from n in names select new XElement("Name",n));
Console.WriteLine(OurGroupMembers);
LINQ TO XML - XELEMENT
XStreamingElement OurGroupMembers = new XStreamingElement("OurGroup", from n in names select new XElement("Name", n));
names[3] = "Tamer";Console.WriteLine(OurGroupMembers);names[2] = "Smer";Console.WriteLine(OurGroupMembers);
XStreamingElement VS. XElement
LINQ TO XML - XSTREAMING
<OurGroup> <Name>M.Hammod</Name> <Name>Golden Man</Name> <Name>Mohammed_807</Name> <Name>Tamer</Name></OurGroup>
<OurGroup> <Name>M.Hammod</Name> <Name>Golden Man</Name> <Name>Smer</Name> <Name>Tamer</Name></OurGroup>
LINQ TO XML - XSTREAMING
xDocument1.Element("BookParticipants").Add( new XElement("BookParticipant", new XAttribute("type", "Editor"), new XElement("FirstName", "Mohammad"), new XElement("LastName", "_807")));
- AddFirst.
- AddBeforeSelf.
- AddAfterSelf.
LINQ TO XML – ADDING ELEMENTS
xDocument1.Element("BookParticipants").Elements("BookParticipant").Where(e => ((string)e.Element("FirstName")) =="Tarek").
Single<XElement>().AddBeforeSelf( new XElement("BookParticipant", new XAttribute("type", "Technical Reviewer"), new XElement("FirstName", "Nawwar"), new XElement("LastName", "soso")));
LINQ TO XML – ADDING ELEMENTS
XElement elementToUpdate = xDocument1.Element("BookParticipants"). Elements("BookParticipant").
Single(e=>((string)e.Element("FirstName")) == "Tarek");
//using Value to Update
elementToUpdate.Element("FirstName").Value = "New_Tarek";
- ReplaceAll
LINQ TO XML - UPDATING
- elementToRemove.Remove();
- xDocument1.Descendants().Where(e => e.Name =="FirstName").Remove();
- xDocument1.Element("BookParticipants").RemoveAll();
LINQ TO XML – REMOVE ELEMENTS
Linq To Sql Demo
LINQ TO SQL
public static IEnumerable<TResult> Select<TSource, TResult>( this IEnumerable<TSource> source, Func<TSource, TResult> selector);
public delegate string MyDelegate(int index); public static string ReturnName(int index) { string[] names3 = new string[] { "Hammod", "Tarek", "Alyan", "Nawwar" }; return names3[index]; } static MyDelegate SDelegate = new MyDelegate(ReturnName);
Console.WriteLine(SDelegate(1));
LINQ – FUNC AND DELEGATES
