Write to a binary file with C#

Question

I'm trying to encrypt a string and write it to a binary file. I want to do the process in reverse. Here is the code I have but it doesn't work.

FileStream stream = new FileStream(saveFileDialog1.OpenFile().ToString(),   FileMode.Create);
BinaryWriter writer = new BinaryWriter(stream);
String temp = "";
serialList.ForEach(delegate(record p)
{ 
    temp = String.Format("{0},{1}#", p.serial, p.option);
    byte[] dataB = System.Text.Encoding.Unicode.GetBytes(String.Format("{0},{1}#", p.serial, p.option));
    byte[] enc = Encrypt(dataB, "gio!");
    writer.Write(enc);
});
writer.Write('1');
writer.Close();
stream.Close();

What is wrong with it??

@zmbq: Creates an empty file, like the question says.

Kendall Frey
– Kendall Frey

2012-06-08 22:31:57 +00:00
Commented Jun 8, 2012 at 22:31 — Kendall Frey
– Kendall Frey, Commented Jun 8, 2012 at 22:31

Alexei Levenkov · Accepted Answer · 2012-06-08 22:41:16Z

6

SaveFileDialog.OpenFile already returns you Stream object. You don't need strange .ToString() call that may or may not give you file name/complete file path.

Essentially your code creates 2 streams: one at location specified in FileOpenDialog, and another - somewhere at relative path with file name equal to result of "Stream.ToString()". First stream (the one you likely looking at) will be empty, as you are not writing anything to it.

Note: consider using using(...) instead of manual .Close calls as it creates safer code (you'll not leave stream non-disposed in case of an exception).

edited Jun 8, 2012 at 22:41

answered Jun 8, 2012 at 22:35

Alexei Levenkov

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Comments

Kendall Frey · Accepted Answer · 2012-06-08 22:33:02Z

2

Before closing the stream, flush it, like this.

writer.Flush();
writer.Close();

Alternatively, you can set writer.AutoFlush to true before you begin writing, but that may be slightly slower.

answered Jun 8, 2012 at 22:33

Kendall Frey

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2 Comments

Alexei Levenkov Over a year ago

+0. Reasonable advice, but no-op: Close performs Flush. Same as calling Dispose with using (which would make for better code in this case).

Kendall Frey Over a year ago

@AlexeiLevenkov: I wondered about that, but the code given suggests it is not being flushed. Interesting.

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