could you explain why?

[David Wang]

HI,
Please look at following code example:
string convert2string(byte [] bys)
{
string string1 = Encoding.ASCII.GetString(bys, 0, 30).TrimEnd(null);

return string1;
}

byte [] allzero = new byte [40];
string dbstr = convert2string(byte);

After I get dbstr(which is empty), I write it to SQL database. When I read
this from database again, and serilize to XML message, I see
����.....��� which means dbstr actually was not empty,
it filled with all "0" inside. Can anybody explain why? How can I get rid of
it? Thank you.

David

[Michael Mayer]

"David Wang" <wg*****@yahoo.com> wrote in message
news:uO***************@TK2MSFTNGP09.phx.gbl...

string convert2string(byte [] bys)
{
string string1 = Encoding.ASCII.GetString(bys, 0, 30).TrimEnd(null);
return string1;
}

byte [] allzero = new byte [40];
string dbstr = convert2string(byte); TYPO: I think you mean convert2string(allzero)
After I get dbstr(which is empty), It is NOT empty... Just because it has non-printable characters
doesn't make it empty.
If you do:
Console.WriteLine("Length is: " + dbstr.Length);

You'll find it has 30 characters (I assume all are ASCII code 0).
byte [] allzero = new byte [40];

creates an array of value-types. So you have 40 bytes, each with a
default value of 0.

I suspect you'll want to add a check in convert2string to look for
all-zero case and return "" instead.

HTH,
Mike

[Jon Skeet]

David Wang <wg*****@yahoo.com> wrote:

Please look at following code example:
string convert2string(byte [] bys)
{
string string1 = Encoding.ASCII.GetString(bys, 0, 30).TrimEnd(null);

return string1;
}

byte [] allzero = new byte [40];
string dbstr = convert2string(byte);

After I get dbstr(which is empty), I write it to SQL database. When I read
this from database again, and serilize to XML message, I see
����.....��� which means dbstr actually was not empty,
it filled with all "0" inside. Can anybody explain why? How can I get rid of
it? Thank you.

Instead of calling TrimEnd (null) which will do nothing, call
TrimEnd ('\0')

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet/
If replying to the group, please do not mail me too

[Jon Skeet]

David Wang <wg*****@yahoo.com> wrote:

Please look at following code example:
string convert2string(byte [] bys)
{
string string1 = Encoding.ASCII.GetString(bys, 0, 30).TrimEnd(null);

return string1;
}

byte [] allzero = new byte [40];
string dbstr = convert2string(byte);

After I get dbstr(which is empty), I write it to SQL database. When I read
this from database again, and serilize to XML message, I see
����.....��� which means dbstr actually was not empty,
it filled with all "0" inside. Can anybody explain why? How can I get rid of
it? Thank you.

Instead of calling TrimEnd (null) which will do nothing, call
TrimEnd ('\0')

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet/
If replying to the group, please do not mail me too