Delphi Blockread in C#

[Tomas Jönsson]

I'm trying to translate at short code snippet Delphi code to C#. Something
that shouldn't be to hard, but I directly turned into a problem that
probably is very simple. Here's the code that I'm wondering about
dbl : double;
....
BlockRead( TheFile, dbl, sizeof(dbl) );
....

All I want to read is a double from a binary file. In C# I wrote:
FileStream fs = new FileStream( fullName, FileMode.Open, FileAccess.Read );
BinaryReader r = new BinaryReader(fs);
....
double dbl = r.ReadDouble();

The value I get from doing this is not what I suspect at all. I've
discovered that reading string need to be done through a UTF7Encoder to work
correctly. My problem might have to to with sometinhg similar here, but how?
( I think I'm sure that I am at the right position before the reading.)

Any ideas would be appriciated!

Thanks/
Tomas

[Miha Markic [MVP C#]]

Hi Tomas,

Depends on how the double was written to the file.
Since you are mentioning UTF7Encoder, is your double written as text?

--
Miha Markic [MVP C#] - RightHand .NET consulting & development
www.rthand.com
Blog: http://cs.rthand.com/blogs/blog_with_righthand/
SLODUG - Slovene Developer Users Group www.codezone-si.info

"Tomas Jönsson" <to***********@not.specified.com> wrote in message
news:%2***************@TK2MSFTNGP10.phx.gbl...

I'm trying to translate at short code snippet Delphi code to C#. Something
that shouldn't be to hard, but I directly turned into a problem that
probably is very simple. Here's the code that I'm wondering about
dbl : double;
...
BlockRead( TheFile, dbl, sizeof(dbl) );
...

All I want to read is a double from a binary file. In C# I wrote:
FileStream fs = new FileStream( fullName, FileMode.Open,
FileAccess.Read );
BinaryReader r = new BinaryReader(fs);
...
double dbl = r.ReadDouble();

The value I get from doing this is not what I suspect at all. I've
discovered that reading string need to be done through a UTF7Encoder to
work correctly. My problem might have to to with sometinhg similar here,
but how? ( I think I'm sure that I am at the right position before the
reading.)

Any ideas would be appriciated!

Thanks/
Tomas

[Octavio Hernandez]

Tomas,

I believe that if you are positioned at the same place in the file, you
should read the same value in both programs. Delphi and C# (.NET) both use
IEEE 754 to represent floating point values. The encoding should have no
influence in this case.

Can you post the sequences of BYTES both programs read from that position?
(16 bytes should be enough)

Regards - Octavio

"Tomas Jönsson" <to***********@not.specified.com> escribió en el mensaje
news:%2***************@TK2MSFTNGP10.phx.gbl...

I'm trying to translate at short code snippet Delphi code to C#. Something
that shouldn't be to hard, but I directly turned into a problem that
probably is very simple. Here's the code that I'm wondering about
dbl : double;
...
BlockRead( TheFile, dbl, sizeof(dbl) );
...

All I want to read is a double from a binary file. In C# I wrote:
FileStream fs = new FileStream( fullName, FileMode.Open,
FileAccess.Read );
BinaryReader r = new BinaryReader(fs);
...
double dbl = r.ReadDouble();

The value I get from doing this is not what I suspect at all. I've
discovered that reading string need to be done through a UTF7Encoder to
work correctly. My problem might have to to with sometinhg similar here,
but how? ( I think I'm sure that I am at the right position before the
reading.)

Any ideas would be appriciated!

Thanks/
Tomas

[Tomas Jönsson]

Oh dear, I wrote "I think I'm sure that I am at the right position before
the reading".
I wasn't!

I apologize for taking your time! Thank you both for answering!

:-}

/Tomas