Updating portion of byte array not working - C# Discussion Boards

28-Aug-12 2:02

I'm trying to update a portion of a byte array with modified data and for some reason it's always unchanged. Any input would be appreciated.

Right now, I have a temporary array that I'm trying to do an array copy for part of the array to update the data. This isn't working. Before that, I didn't have a temporary array and was doing basically the same thing with the destination array. The data locations I'm writing to are 0 after the update, but I am seeing the correct data in my tempStrings and convertStringToBytes method.

private void updateDatWithData()
{
            int returnCode = 0;
            byte[] tempByteArr = new byte[Dat.Length];

            //ex. 005R00099 ==> 005 R 00099 ==> 005 52 00099 ==> 00 55 20 00 99
            String tempString = (configNum[0].ToString() + configNum[1].ToString()); //ex. 00
            byte tempByte = 0;
            returnCode = convertStringToByte(tempString, ref tempByteArr[index + 4]); // ??Dat isn't getting updated below.

...
            Array.Copy(tempByteArr, (index+ 4), Dat, (index + 4), 5);
}

private int convertStringToByte(String theString, ref byte theByte)
{
            int returnCode = 1;
            try
            {
                theByte = System.Convert.ToByte(theString);
            }            
            return returnCode;
}

Keith Barrow28-Aug-12 2:32

28-Aug-12 2:32

You have a try without a catch or finally, so I don't see how your code is compiling. Simplifying your problem:

private int convertStringToByte(String theString, ref byte theByte)
    {
        theByte = System.Convert.ToByte(theString);
        return 1;
    }

    public void RunSnippet()
    {
        byte[] tempByteArr = new byte[]{1};
        convertStringToByte("3", ref tempByteArr[0]);
        Console.WriteLine(tempByteArr[0]);
    }

The above code works, so the basic logic of what you have is OK, just an implementation problem.

I'd suggest a different methodology. It looks like you are trying to implement Byte.TryParse method, you may want to look at it. If you need more information than a plain boolean, implementing your own is easy:

public static int ConvertStringToByte(string s, out byte result)
    {
        try
        {
            theByte = System.Convert.ToByte(theString);

        }
        catch
        {
            return 0;
            //Or whatever - don't catch "all exceptions" like this!
        }
        return 1;
    }

Sort of a cross between Lawrence of Arabia and Dilbert.[^]
-Or-
A Dead ringer for Kate Winslett[^]

MichCl28-Aug-12 2:38

28-Aug-12 2:38

My code actually has a catch for my try. I just didn't include it here to simplify.

So it works for you basically as-is?

Keith Barrow28-Aug-12 2:47

28-Aug-12 2:47

It is working. Given what you have said, the problem could well be in the catch. You need to step through your code to determine what is happening exactly, unless someone here come up with a full solution.

Sort of a cross between Lawrence of Arabia and Dilbert.[^]
-Or-
A Dead ringer for Kate Winslett[^]

MichCl28-Aug-12 3:16

28-Aug-12 3:16

Ok. I figured it out. I was constructing one of my strings wrong and wound up with one that was 282, so it was throwing an exception when it tried to convert to byte and never got to copying the temp array to my final Dat array.

Keith Barrow28-Aug-12 3:54

28-Aug-12 3:54

Glad you found it!

Sort of a cross between Lawrence of Arabia and Dilbert.[^]
-Or-
A Dead ringer for Kate Winslett[^]

Shameel28-Aug-12 4:00

Shameel

28-Aug-12 4:00

Lesson learnt: Never write an empty catch block.

Keith Barrow28-Aug-12 4:32

28-Aug-12 4:32

void GetNameChangedToProtectTheInnocent()
   {
       try
       {
           ...
       }
       catch
       {
           //Bury the error, like the classic site
       }
   }

There you go - not empty! Written by yours truly, only 10mins ago Blush | :O

. In my defence, it's important that the site doesn't throw errors and this is what the rest of the site does. Unsure | :~

Sort of a cross between Lawrence of Arabia and Dilbert.[^]
-Or-
A Dead ringer for Kate Winslett[^]

DaveyM6928-Aug-12 5:16

DaveyM69

28-Aug-12 5:16

Fair enough, but it should at least be logged for investigation. If it's unimportant and not worth logging then it should be handled in code so the exception never arises.

Dave

Binging is like googling, it just feels dirtier.
Please take your VB.NET out of our nice case sensitive forum.
Astonish us. Be exceptional. (Pete O'Hanlon)

BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)

Keith Barrow28-Aug-12 6:07

28-Aug-12 6:07

I was being a bit (OK, very) toungue-in-cheek. 99.99% of the time I really wouldn't do this. In this case he exception is very unimportant, for various reasons I'd have to write my own logging infrastructure (which would take longer than the rest of the change, and my code is slated for replacement by an MVC app very soon) and I can't handle in code as the try-block is calling out to an asmx service and I'm guarding against technical errors. I could, I suppose tighten which errors are being caught.

Sort of a cross between Lawrence of Arabia and Dilbert.[^]
-Or-
A Dead ringer for Kate Winslett[^]

MichCl28-Aug-12 4:33

28-Aug-12 4:33

Actually, my catch block had a lot in it. It was just not included in my post!

Shameel28-Aug-12 4:43

Shameel

28-Aug-12 4:43

In Visual Studio, You can enable breaking at an exception even when it is caught and handled. This will be very useful during debugging.

MichCl28-Aug-12 2:43

28-Aug-12 2:43

I wonder if it's my data. My strings are "00", "55", "20", "00", and "99".

hello

ri198728-Aug-12 1:10

ri1987

28-Aug-12 1:10

plz i need link of proggrams in c# concern with panorama images (stitching image)
help me

Re: hello

Keith Barrow28-Aug-12 1:20