How to: Execute action when data is received

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This article is intended to demonstrate the use of actionblock.

Approximate process:

Input path--Read bytes--compute--Transfer to print

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2. Demonstrates how to provide delegates to exectution dataflow blocks.
4. class Dataflowexecutionblocks
6. {
8. ???? //Calculation file contains a total of 0 bytes
10. ???? Static int Countbytes (string path)
12. ???? {
14. ???????? byte [] buffer = newbyte[1024];
16. ???????? int totalzerobytesread = 0;
18. ???????? using (var fileStream = file.openread (path))
20. ???????? {
22. ???????????? int bytesread = 0;
24. ???????????? Do
26. ???????????? {
28. ???????????????? Bytesread = filestream.read (buffer, 0, buffer. Length);
30. ???????????????? Totalzerobytesread + = buffer. Count (b = = = 0);
32. ????????????} while (Bytesread > 0);
34. ????????}
36. ?
38. ???????? return Totalzerobytesread;
40. ????}
42. ?
44. ???? Static void Run (string[] args)
46. ???? {
48. ???????? //Create a temp directory
50. ???????? string tempfile = Path.gettempfilename ();
52. ?
54. ???????? //Random Write Data
56. ???????? using (var fileStream = File.openwrite (tempfile))
58. ???????? {
60. ???????????? Random rand = new random ();
62. ???????????? byte [] buffer = newbyte[1024];
64. ???????????? for (int i = 0; i <; i++)
66. ???????????? {
68. ???????????????? Rand. Nextbytes (buffer);
70. ???????????????? FileStream.Write (buffer, 0, buffer.) Length);
72. ????????????}
74. ????????}
76. ?
78. ???????? //Create a Actionblock<int> object to print the number of bytes read to
80. ???????? var printresult = new actionblock<int> (zerobytesread =
82. ???????? {
84. ???????????? Console.WriteLine ("{0} contains {1} zero bytes.",
86. ???????????????? Path.getfilename (tempfile), zerobytesread);
88. ????????});
90. ?
92. ???????? //Genesis a transformblock<string, int> object to invoke the Countbytes function and return the result of the calculation
94. ???????? var countbytes = New transformblock<string, int> (
96. ???????????? New func<string, int> (countbytes));
98. ?
100. ???????? //Two blocks are linked together:tranformblock<string,int> objects and Actionblock objects.
102. ???????? Countbytes.linkto (Printresult);
104. ?
106. ???????? //Create a continuous task: When transformblock<string, int> finishes, notifies the print result is complete
108. ???????? CountBytes.Completion.ContinueWith (delegate {printresult.complete ();});
110. ?
112. ???????? //Enter temp directory
114. ???????? Countbytes.post (Tempfile);
116. ?
118. ???????? //End of logo
120. ???????? Countbytes.complete ();
122. ?
124. ???????? //wait for print to finish
126. ???????? printResult.Completion.Wait ();
128. ?
130. ???????? File.delete (Tempfile);
132. ????}
134. }

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Transformblock: Generally used for transmission and calculation. A map operation in a function-like programming.

Func<tinput,toutput> delegate, through post, enter a tinput parameter.

Complete (), indicating completed

Completion task, completed, the current task ends. Essentially, Tranformblock runs in a task.

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Actionblock:

The Action<tinput> action delegate, a single input, performs operations such as printing.

There are also complete () and completion tasks.

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At the same time, the above two support async methods:

Transform

Action

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2. var countbytesasync = New transformblock<string, int> (async Path = =
4. {
6. ???? byte [] buffer = newbyte[1024];
8. ???? int totalzerobytesread = 0;
10. ???? using (var fileStream = new fileStream (
12. ???????? Path, FileMode.Open, FileAccess.Read, FileShare.Read, 0x1000, true))
14. ???? {
16. ???????? int bytesread = 0;
18. ???????? Do
20. ???????? {
22. ???????????? //Asynchronously read from the file stream.
24. ???????????? Bytesread = await fileStream. Readasync (buffer, 0, buffer.) Length);
26. ???????????? Totalzerobytesread + = buffer. Count (b = = = 0);
28. ????????} while (Bytesread > 0);
30. ????}
32. ?
34. ???? return Totalzerobytesread;
36. });

How to: Execute action when data is received