Intake 37 linq1
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This document discusses Language Integrated Query (LINQ) and some of the C# 3.0 enhancements that support LINQ, such as implicitly typed local variables. It also provides an example of using a delegate and generic method to filter an integer array, allowing the filtering algorithm to be specified by the calling application code. The example shows how an application developer can define a filtering method or use an anonymous method to filter the array to return only odd numbers.
![Solution
• Solution
public delegate bool IntFilter(int i);
public class Common
{
public static int[] FilterArray(int[] ints, IntFilter filter)
{
ArrayList aList = new ArrayList();
foreach(int I in ints)
{
if(filter(i))
{aList.Add(i);}
}
return((int[])aList.ToArray(typeof(int)));
}
} mmouf@2017](https://image.slidesharecdn.com/intake37linq1-170215162333/85/Intake-37-linq1-4-320.jpg)
![The Application Code Developer (I)
Class MyApplication
{
public static bool IsOdd(int i)
{
return ((i % 2)==1);
}
public static void Main()
{
int[] nums = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
int[] fnum = Common.FilterArray(nums, MyApplication.IsOdd);
foreach(int i in fnum)
Console.WriteLine(i);
}
}
mmouf@2017](https://image.slidesharecdn.com/intake37linq1-170215162333/85/Intake-37-linq1-5-320.jpg)
![The Application Code Developer Anonymous
method “C#2.0” (II)
Class MyApplication
{
public static void Main()
{
int[] nums = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
int[] fnum = Common.FilterArray(nums, delegate(int i)
{return((i%2)==1);});
foreach(int i in fnum)
Console.WriteLine(i);
}
}
mmouf@2017](https://image.slidesharecdn.com/intake37linq1-170215162333/85/Intake-37-linq1-6-320.jpg)
Intake 37 linq1
- 1. Language INtegrated Query (LINQ) Eng. Mahmoud Ouf Lecture 1 mmouf@2017
- 2. C# 3.0 Enhancement for LINQ • Implicitly Typed Local Variables and Arrays • Object Initializers • Auto Implemented Properties • Collection Initializers • Extension Methods • Anonymous Types mmouf@2017
- 3. Example A Common Code developer wants to create a generic method for filtering an array of integers, but with the ability to specify the algorithm for filtration to the Application developer mmouf@2017
- 4. Solution • Solution public delegate bool IntFilter(int i); public class Common { public static int[] FilterArray(int[] ints, IntFilter filter) { ArrayList aList = new ArrayList(); foreach(int I in ints) { if(filter(i)) {aList.Add(i);} } return((int[])aList.ToArray(typeof(int))); } } mmouf@2017
- 5. The Application Code Developer (I) Class MyApplication { public static bool IsOdd(int i) { return ((i % 2)==1); } public static void Main() { int[] nums = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}; int[] fnum = Common.FilterArray(nums, MyApplication.IsOdd); foreach(int i in fnum) Console.WriteLine(i); } } mmouf@2017
- 6. The Application Code Developer Anonymous method “C#2.0” (II) Class MyApplication { public static void Main() { int[] nums = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}; int[] fnum = Common.FilterArray(nums, delegate(int i) {return((i%2)==1);}); foreach(int i in fnum) Console.WriteLine(i); } } mmouf@2017