[. NET] CastingEnumerable

Preface:
It is inevitable to write a program and use a custom function to transform the crop array.
I wrote an object for this action and shared it with you.

Note:
This object has the following features:
1. Only when it is used can it be transformed. The entire transformed array copy will not be created in the memory.
2. You can add parameters during transformation.

Example:
View source
 

01 namespace CLK. Collections. ConsoleApplication
02 {
03 public class User
04 {
05 public string LastName = string. Empty;
06
07 public string FirstName = string. Empty;
08}
09
10 public class Data
11 {
12 public string DisplayName = string. Empty;
13}
14
15 class Program
16 {
17 static void Main (string [] args)
18 {
19 User [] userArray = new User [2];
20
21 userArray [0] = new User ();
22 userArray [0]. LastName = "Chou ";
23 userArray [0]. FirstName = "Clark ";
24
25 userArray [1] = new User ();
26 userArray [1]. LastName = "AAAA ";
27 userArray [1]. FirstName = "BBBBB ";
28
29
30 IEnumerable <Data> dataList = CreateDataList (userArray ,"★★★★★");
31 foreach (Data data in dataList)
32 {
33 Console. WriteLine (data. DisplayName );
34}
35 Console. WriteLine ("");
36
37
38 Console. WriteLine ("End ");
39 Console. ReadLine ();
40}
41
42 static IEnumerable <Data> CreateDataList (IEnumerable <User> userList, string decorator)
43 {
44 return new CastingEnumerable <Data, User> (userList, delegate (User user) {return CreateData (user, decorator );});
45}
46
47 static Data CreateData (User user, string decorator)
48 {
49 Data data = new Data ();
50 data. DisplayName = decorator + user. LastName + "." + user. FirstName + decorator;
51 return data;
52}
53}
54}

Program example:
View source
 

01 namespace CLK. Collections
02 {
03 public class CastingEnumerable <TResult, TSource>: IEnumerable <TResult>
04 {
05 // Properties
06 private readonly IEnumerable <TSource> _ sourceEnumerable;
07
08 private CastingEnumerableDelegate <TResult, TSource> _ enumerableDelegate;
09
10
11 // Construction
12 public CastingEnumerable (IEnumerable <TSource> sourceEnumerable, CastingEnumerableDelegate <TResult, TSource> enumerableDelegate)
13 {
14 # region Require
15
16 if (sourceEnumerable = null) throw new ArgumentNullException ();
17 if (enumerableDelegate = null) throw new ArgumentNullException ();
18
19 # endregion
20_sourceenumerable = sourceEnumerable;
21 _ enumerableDelegate = enumerableDelegate;
22}
23
24
25 // Member
26 public IEnumerator <TResult> GetEnumerator ()
27 {
28 return new CastingEnumerator <TResult, TSource> (_ sourceEnumerable. GetEnumerator (), _ enumerableDelegate );
29}
30
31 System. Collections. IEnumerator System. Collections. IEnumerable. GetEnumerator ()
32 {
33 return this. GetEnumerator ();
34}
35}
36}

View source
 

01 namespace CLK. Collections
02 {
03 public class CastingEnumerator <TResult, TSource>: IEnumerator <TResult>
04 {
05 // Properties
06 private readonly IEnumerator <TSource> _ sourceEnumerator;
07
08 private readonly CastingEnumerableDelegate <TResult, TSource> _ enumerableDelegate;
09
10 private TResult _ currentResult = default (TResult );
11
12
13 // Construction
14 public CastingEnumerator (IEnumerator <TSource> sourceEnumerator, CastingEnumerableDelegate <TResult, TSource> enumerableDelegate)
15 {
16 # region Require
17
18 if (sourceEnumerator = null) throw new ArgumentNullException ();
19 if (enumerableDelegate = null) throw new ArgumentNullException ();
20
21 # endregion
22 _ sourceEnumerator = sourceEnumerator;
23 _ enumerableDelegate = enumerableDelegate;
24}
25
26 public virtual void Dispose ()
27 {
28_sourceenumerator. Dispose ();
29 _ currentResult = default (TResult );
30}
31
32
33 // Member
34 public TResult Current
35 {
36 get
37 {
38 return _ currentResult;
39}
40}
41
42 object System. Collections. IEnumerator. Current
43 {
44 get
45 {
46 return this. Current;
47}
48}
49
50 public bool MoveNext ()
51 {
52 if (_ sourceEnumerator. MoveNext () = true)
53 {
54 _ currentResult = _ enumerableDelegate (_ sourceEnumerator. Current );
55 return true;
56}
57 return false;
58}
59
60 public void Reset ()
61 {
62 _ sourceEnumerator. Reset ();
63 _ currentResult = default (TResult );
64}
65}
66}

View source
 

1 public delegate TResult CastingEnumerableDelegate <TResult, TSource> (TSource source );

 

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