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Kdahlby 200908 Stldodn Linqinternals 090903222505 Phpapp01

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Kdahlby 200908 Stldodn Linqinternals 090903222505 Phpapp01

  1. 1.      
  2. 2.       
  3. 3.   o o  o o
  4. 4.  o   o
  5. 5. var entry = new { Dim entry = New With { _ Title = "Dear Diary", .Title = "Dear Diary", _ DateTime.Now DateTime.Now _ }; } Console.WriteLine("{0:d}: {1}", Console.WriteLine("{0:d}: {1}", _ entry.Now, entry.Title); entry.Now, entry.Title) var Dim
  6. 6.  static Module  using Imports  Imports System.Runtime.CompilerServices Module StringExtensions <Extension()> _ Public Sub Print(ByVal aString As String) Console.WriteLine(aString) End Sub End Module Dim hello = "Hello from StringExtensions" hello.Print()
  7. 7.  this static void ForEach<T>(this IEnumerable<T> source, Action<T> action) { foreach (T o in source) action(o); }  delegate void Action(); delegate void Action<T>(T arg); delegate void Action<T1, T2>(T1 arg1, T2 arg2); delegate TResult Func<TResult>(); delegate TResult Func<T, TResult>(T arg); delegate TResult Func<T1, T2, TResult>(T1 arg1, T2 arg2);
  8. 8.  delegate string MyDelegate(int i); static string MyMethod(int i) { … } MyDelegate del1 = new MyDelegate(MyMethod); // C# 1.0 MyDelegate del2 = delegate(int i) { … }; // C# 2.0 MyDelegate del3 = MyMethod; // C# 2.0 MyDelegate del4 = (int i) => { … }; // C# 3.0 Func<int, string> del5 = i => { … }; // C# 3.0  Dim del4 As MyDelegate = Function(i As Integer) …
  9. 9.    Expression<Func<int, int>> inc = (a => a + 1);  ParameterExpression CS$a; Expression<Func<int, int>> inc = Expression.Lambda<Func<int, int>>( Expression.Add( CS$a = Expression.Parameter(typeof(int), "a"), Expression.Constant(1, typeof(int))), new ParameterExpression[] { CS$a });
  10. 10.  var names = from s in Students where s.Age % 2 == 0 orderby s.Name descending select s.Name;  IEnumerable<string> names = Students.Where(s => s.Age % 2 == 0) .OrderByDescending(s => s.Name) .Select(s => s.Name);
  11. 11.  o o  o  o
  12. 12.  o   o  o   o   o o  o   o   o  o 
  13. 13.              
  14. 14.  from x1 in e1 join x2 in e2 on k1 equals k2 …  from * in ( e1 ) . Join( e2 , x1 => k1 , x2 => k2 , (x1 , x2) => new { x1 , x2 }) …  o this o o o o
  15. 15.  o EqualityComparer<TKey>.Default  o Equals() GetHashcode() o  IEqualityComparer<TKey> o o
  16. 16.  into o o Func<TOuter, TInner, TResult> resultSelector  into o o o Func<TOuter, IEnumerable<TInner>, TResult> resultSelector  o DefaultIfEmpty() from x1 in e1 join x2 in e2 on k1 equals k2 into j from xj in j . DefaultIfEmpty() …
  17. 17.  from o IEnumerable<T>  from x1 in e1 from x2 in e2 …  from * in ( e1 ) . SelectMany( x1 => e2 , ( x1 , x2 ) => new { x1 , x2 } ) …  * o
  18. 18.   o IEnumerable<T>  o yield return  o o o o
  19. 19.  o o  o • foreach o  o  o
  20. 20.  o o IEnumerable<>  o o EnumerableRowCollection<DataRow> AsEnumerable(this DataTable source) o EnumerableRowCollectionExtensions  o Cast<T>() OfType<T>() o foreach from MyType obj in MyArrayList …
  21. 21.   o IQueryable<T> public interface IQueryable : IEnumerable { Type ElementType { get; } Expression Expression { get; } IQueryProvider Provider { get; } } public interface IQueryable<T> : IEnumerable<T>, IQueryable, IEnumerable { }
  22. 22.  public interface IQueryProvider { IQueryable CreateQuery(Expression expression); IQueryable<TElement> CreateQuery<TElement>(Expression expression); object Execute(Expression expression); TResult Execute<TResult>(Expression expression); }
  23. 23. public static TSource First<TSource>( this IQueryable<TSource> source) { return source.Provider.Execute<TSource>( Expression.Call(null, ((MethodInfo) MethodBase.GetCurrentMethod()) .MakeGenericMethod(new Type[] { typeof(TSource) }), new Expression[] { source.Expression } ) ); }
  24. 24.  IEnumerable IQueryable   o o  o o
  25. 25.   o  o o o

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