C# byte array doesn't allocate correctly

Question

Screenshot of weird problem

I'm trying to serialize an object in C#. I got the object size and saved it in a variable, size1 on line 207 in above screenshot. Size1 has a value of 160. Then I used size1 to allocate an array of bytes called buf in line 210. Buf comes out to be a 2 byte array! How can this be?!

The image also shows the values of local variables during runtime. As it is the runtime behavior that I want to illustrate, the image is appropriate. Also, no one is likely to believe me when I say byte[] buf = new byte[size1] results in buf having 2 bytes despite size1 has a value of 160! The image of runtime behaviors makes my case. — Thomas Nguyen
– Thomas Nguyen, Commented Aug 14, 2013 at 18:18
The image would be appropriate if you include some sample source code that we can copy into our own IDEs and try it for ourselves. — Austin Salonen
– Austin Salonen, Commented Aug 14, 2013 at 18:20

Scott Chamberlain · Accepted Answer · 2013-08-14 18:25:59Z

8

The problem is here

byte[] buf = new byte[size1];
byte[] buf2 = new byte[16];
buf = b.ReadBytes(...); //<----

You are replacing buf with the result of ReadBytes. That throws away your original array and replaces it with the array that was returned from ReadBytes (which in your case was a two byte array)

answered Aug 14, 2013 at 18:25

Scott Chamberlain

128k37 gold badges299 silver badges447 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Thomas Nguyen Over a year ago

Exactly! Can't believe I commit a classic newbie mistake, which is the values of the local variables as shown in the debug window are the state of the program at the point the program stops/breaks, not some arbitrary lines before the break point. I still have to figure out the problem with b.ReadBytes(...) but at least I will be going down the correct alley. Thanks Scott!

Martin Smith · Accepted Answer · 2013-08-14 19:19:52Z

4

ReadBytes() returns a byte[]. When you write

buf = b.ReadBytes(Marshal.SizeOf(firstRecord));

then buf points at a completely different byte[] that equals whatever b.ReadBytes() returned.

edited Aug 14, 2013 at 19:19

Martin Smith

457k97 gold badges777 silver badges886 bronze badges

answered Aug 14, 2013 at 18:27

Rohan

3592 silver badges16 bronze badges

Comments

Community · Accepted Answer · 2017-05-23 10:31:53Z

0

It looks like you're trying to convert some object into a byte array, this answer may help. Convert any object to a byte[]

edited May 23, 2017 at 10:31

CommunityBot

11 silver badge

answered Aug 14, 2013 at 18:33

newb

1411 silver badge2 bronze badges

Collectives™ on Stack Overflow

C# byte array doesn't allocate correctly

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related