Copy byte array to another byte array in C#

Question

There are two byte arrays which are populated with different values.

byte[] Array1 = new byte[5];
byte[] Array2 = new byte[5];

Then, I need Array1 to get exactly the same values as Array2.

By typing Array1 = Array2 I would just set references, this would not copy the values.

What might be the solution?

EDIT:

All answers are good and all solutions work. The code from the first solution looks visually more descriptive for my particular case.

Array1 = Array2.ToArray();

and

Array1.CopyTo(Array2, 0);

as well as

Buffer.BlockCopy(Array2, 0, Array1, 0, 5);

Possible duplicate of Copy Bytes from a byte array to a specific position of another Byte array in C# — Frank Bryce
– Frank Bryce, Commented Jan 17, 2016 at 0:28
No, the first array should be an exact copy of the second. But it should not be linked in any way with it. Should not be a pointer. — acoder
– acoder, Commented Jan 17, 2016 at 0:32
"Both answers are good and both solutions work". As well as Buffer.BlockCopy mentioned in the first comment, any Array.Copy overload, Array.Clone — Ivan Stoev
– Ivan Stoev, Commented Jan 17, 2016 at 9:38

Frank Bryce · Accepted Answer · 2016-01-17 14:15:51Z

60

One solution courtesy of Linq...

Array1 = Array2.ToArray();

EDIT: you do not need to allocate space for Array1 before using this Linq call. The allocation for Array1 is done within ToArray(). More complete example below

byte[] Array2 = new byte[5];
// set values for Array2
byte[] Array1 = Array2.ToArray();

edited Jan 17, 2016 at 14:15

answered Jan 17, 2016 at 0:29

Frank Bryce

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5 Comments

Enigmativity Over a year ago

This is a fairly neat solution, but since the OP has allocated the destination array already and has said, "I just set references, I don't copy the values", then I think it would be prudent to point out in your answer that you are creating a new reference and not copying the values to the pre-allocated array.

Frank Bryce Over a year ago

Will do, the statement in the OP "By typing Array1 = Array2 I just set references, I don't copy the values" I thought was an attempt to say that the array reference was copied, and that the values themselves were not duplicated. This also seemed to be the case in his later comment "But it should not be linked in any way with it.", which I thought was an attempt to say Array1[0] = (byte) 1 will do nothing to the values in Array2

Enigmativity Over a year ago

Yes, I agree. That's why I think your answer is a fairly neat solution. I just thought that the OP might need to understand the mechanics a little more deeply.

acoder Over a year ago

As I understood, Array2.ToArray() allocates a new array. What if Array1 = Array2.ToArray(); is executed multiple times, in a for loop for example? Does these allocations remain in memory?

Frank Bryce Over a year ago

@acoder C# has a garbage collection system, so if you have no more references to allocated memory, then the values will be cleaned up. I wouldn't recommend allocating new memory in a loop just to ignore the values quickly thereafter.

Qwertiy · Accepted Answer · 2022-10-26 09:47:25Z

50

Array2.CopyTo(Array1, 0);

Microsoft Docs

edited Oct 26, 2022 at 9:47

answered Jan 17, 2016 at 0:32

Qwertiy

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3 Comments

Kemp Over a year ago

Six years later, I feel it's worth pointing out that this should be Array2.CopyTo(Array1, 0). The line as given does the copy in the opposite direction to what was asked.

Qwertiy Over a year ago

@Kemp, yep, fixed.

Michael Seifert Over a year ago

A little more details would've been helpful. The integer parameter is from which element it should copy. Microsoft docs are unreadable as always. I believe Array1 needs to be pre-allocated, I'll find out soon enough :-)

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