First steps in C#......could someone help please ?

[Bart]

Could someone explain me what is wrong with this code ?

I gives me a compile error:

Error 1 Use of unassigned local variable 'fileStreamObje ct' C:\Documents and
Settings\Bart\L ocal Settings\Applic ation Data\Temporary
Projects\Window sApplication1\e mployeeReader.c s 22 17 WindowsApplicat ion1
The code is:

public void Write(string filename, Employee emp)
{
FileStream fileStreamObjec t;
try
{
fileStreamObjec t = new FileStream(file name,
FileMode.Create );
BinaryFormatter binaryFormatter = new BinaryFormatter ();
binaryFormatter .Serialize(file StreamObject, emp);
}
finally
{
fileStreamObjec t.Close(); <-------- gives an error !!!
}
}

Thanks a lot

Bart

[Tom Porterfield]

Bart wrote:

Could someone explain me what is wrong with this code ?

I gives me a compile error:

Error 1 Use of unassigned local variable 'fileStreamObje ct' C:\Documents
and Settings\Bart\L ocal Settings\Applic ation Data\Temporary
Projects\Window sApplication1\e mployeeReader.c s 22 17 WindowsApplicat ion1
The code is:

public void Write(string filename, Employee emp)
{
FileStream fileStreamObjec t;
try
{
fileStreamObjec t = new FileStream(file name,
FileMode.Create );
BinaryFormatter binaryFormatter = new BinaryFormatter ();
binaryFormatter .Serialize(file StreamObject, emp);
}
finally
{
fileStreamObjec t.Close(); <-------- gives an error !!!
}
}

Two things, change your declaration to as follows:

FileStream fileStreamObjec t = null;

Then in your finally wrap your close in a null check:

if (fileStreamObje ct != null)
fileStreamObjec t.Close();
--
Tom Porterfield

[Bart]

Two things, change your declaration to as follows:

>
FileStream fileStreamObjec t = null;

Then in your finally wrap your close in a null check:

if (fileStreamObje ct != null)
fileStreamObjec t.Close();
--
Tom Porterfield

That does the trick......than ks for the quick reply :)

Bart

[Jon Skeet [C# MVP]]

<"Bart" <@>wrote:

Two things, change your declaration to as follows:

FileStream fileStreamObjec t = null;

Then in your finally wrap your close in a null check:

if (fileStreamObje ct != null)
fileStreamObjec t.Close();
--
Tom Porterfield

That does the trick......than ks for the quick reply :)

That does the trick, but a better solution would be to use a "using"
statement:

using (Stream fileStream = new FileStream(file name, FileMode.Create ))
{
BinaryFormatter binaryFormatter = new BinaryFormatter ();
binaryFormatter .Serialize(file StreamObject, emp);
}

The "using" statement automatically calls Dispose for you, creating a
try/finally itself.

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

[Ben Voigt]

Here's the reason the compiler complained:

The code is:

public void Write(string filename, Employee emp)
{
FileStream fileStreamObjec t;
try
{
fileStreamObjec t = new FileStream(file name,
FileMode.Create );

If this line fails, then there is no FileStream object....

BinaryFormatter binaryFormatter = new BinaryFormatter ();
binaryFormatter .Serialize(file StreamObject, emp);
}
finally
{
fileStreamObjec t.Close(); <-------- gives an error !!!

....and this isn't meaningful when that happens.

The using block is best, another fix is to move the fileStreamObjec t
initialization above the try block:

FileStream fileStreamObjec t = new FileStream(file name, FileMode.Create ); //
if this fails, the whole try/catch isn't executed
try {

}
}

Thanks a lot

Bart

[Bart]

using (Stream fileStream = new FileStream(file name, FileMode.Create ))

{
BinaryFormatter binaryFormatter = new BinaryFormatter ();
binaryFormatter .Serialize(file StreamObject, emp);
}

The "using" statement automatically calls Dispose for you, creating a
try/finally itself.

Thanks for your reply

Does this mean I don't have to close the stream myself ?

by the way
I guess : binaryFormatter .Serialize(file StreamObject, emp);
Should be : binaryFormatter .Serialize(file Stream, emp);

right ?

Bart

[Michael Nemtsev]

Hello Bart,

BDoes this mean I don't have to close the stream myself ?

yep, the using statement will dispose the object (calls Dispose method) when
it is out of scope http://msdn2.microsoft.com/en-us/library/yh598w02.aspx

---
WBR,
Michael Nemtsev [C# MVP] :: blog: http://spaces.live.com/laflour

"The greatest danger for most of us is not that our aim is too high and we
miss it, but that it is too low and we reach it" (c) Michelangelo

[Jon Skeet [C# MVP]]

<"Bart" <@>wrote:

using (Stream fileStream = new FileStream(file name, FileMode.Create ))
{
BinaryFormatter binaryFormatter = new BinaryFormatter ();
binaryFormatter .Serialize(file StreamObject, emp);
}

The "using" statement automatically calls Dispose for you, creating a
try/finally itself.

Thanks for your reply

Does this mean I don't have to close the stream myself ?

Yup. You do need to remember to use the "using" statement though :) The
same goes for any type implementing IDisposable.

by the way
I guess : binaryFormatter .Serialize(file StreamObject, emp);
Should be : binaryFormatter .Serialize(file Stream, emp);

Indeed. Cut and paste error, I'm afraid.

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

[Bart]

yep, the using statement will dispose the object (calls Dispose method)

when it is out of scope
http://msdn2.microsoft.com/en-us/library/yh598w02.aspx

Hi Michael ,

Thanks for the reply....I think I am going to like C# and .net

Bart