FileStream Beginread

[Lou]

I can't get it to work. Please help...
-louie

hPipe = CreateFile(conn ectionString,

GENERIC_WRITE | GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRIT E, 0,

OPEN_EXISTING, FILE_ATTRIBUTE_ NORMAL,HANDLE.Z ero);

if ((hPipe.ToInt32 ()) == INVALID_HANDLE_ VALUE)

{

blnConnected=fa lse;

return false;

}

//start an asyncronys read

IAsyncResult iAR;

byte[] byRequest=new byte[4095];

iAR=myStream.Be ginRead(byReque st,0,4096,ASync FileCallBackRea d(iAR),myStream )
;

public void ASyncFileCallBa ckRead(IAsyncRe sult iAR)

{

System.Text.ASC IIEncoding EnAscii;

System.Text.ASC IIEncoding EnUNI;

int byteCount;

string recData;

byte recReq[]=new byte[(Convert.ToByte (iAR.AsyncState )];

byteCount=myStr eam.EndRead(iAR );
recData = EnAscii.GetStri ng(recReq,0,byt eCount);

[Jon Skeet [C# MVP]]

Lou <lo********@com cast.net> wrote:

I can't get it to work. Please help...
-louie
<snikp>
byte[] byRequest=new byte[4095];
iAR=myStream.Be ginRead(byReque st,0,4096,ASync FileCallBackRea d(iAR),myStream )
That's a bad start to begin with - you've asked it to read up to 4096
bytes, but only allocated 4095.
public void ASyncFileCallBa ckRead(IAsyncRe sult iAR)

{

System.Text.ASC IIEncoding EnAscii;
System.Text.ASC IIEncoding EnUNI;
You're declaring these variables, but never setting their values.
int byteCount;

string recData;

byte recReq[]=new byte[(Convert.ToByte (iAR.AsyncState )];

Why are you trying to convert iAR.AsyncState to a byte, and why are you
creating a new byte array?

I would expect you to pass byRequest as your state, rather than the
stream (as you apparently have a reference to the stream elsewhere - it
might well be a good idea to put *both* in the state, as a separate
type), and then just cast it back to a byte array. As it is, you're
completely ignoring whatever you've actually read.

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

[Lou]

Can you please show me an example.

"Jon Skeet [C# MVP]" <sk***@pobox.co m> wrote in message
news:MP******** *************** *@msnews.micros oft.com...

Lou <lo********@com cast.net> wrote:

I can't get it to work. Please help...
-louie
<snikp>

byte[] byRequest=new byte[4095];

iAR=myStream.Be ginRead(byReque st,0,4096,ASync FileCallBackRea d(iAR),myStream )
That's a bad start to begin with - you've asked it to read up to 4096
bytes, but only allocated 4095.

public void ASyncFileCallBa ckRead(IAsyncRe sult iAR)

{

System.Text.ASC IIEncoding EnAscii;
System.Text.ASC IIEncoding EnUNI;

You're declaring these variables, but never setting their values.

int byteCount;

string recData;

byte recReq[]=new byte[(Convert.ToByte (iAR.AsyncState )];

Why are you trying to convert iAR.AsyncState to a byte, and why are you
creating a new byte array?

I would expect you to pass byRequest as your state, rather than the
stream (as you apparently have a reference to the stream elsewhere - it
might well be a good idea to put *both* in the state, as a separate
type), and then just cast it back to a byte array. As it is, you're
completely ignoring whatever you've actually read.

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

[Lou]

I have the code in vb >Net and need to convert it to C#
It works great in VB .Net????
VB Code

'get handle to the pipe

Private Sub btnClient_Click (ByVal sender As System.Object, ByVal e As
System.EventArg s) Handles btnClient.Click

pipeHandle = CreateFile(txtI nput.Text, DesiredAccess.G ENERIC_READ Or
DesiredAccess.G ENERIC_WRITE, _

ShareMode.FILE_ SHARE_READ Or ShareMode.FILE_ SHARE_WRITE, _

secAttr, CreationDisposi tion.OPEN_EXIST ING, _

FlagsAndAttribu tes.FILE_FLAG_O VERLAPPED, IntPtr.Zero)

' Verify we have a good handle.

If (pipeHandle.ToI nt32() = INVALID_HANDLE_ VALUE) Then

MessageBox.Show ("Can't open the pipe port, " + _

"make sure it's installed and not in use.", _

"pipePort Error", _

End If

' Open a stream based on the namedpipe handle.

Try

PS = New FileStream(pipe Handle, FileAccess.Read Write, True, 4095, True)

'' Display a success message.

lblPipeHandle.T ext = pipeHandle.ToSt ring

'start async read

Dim byRequest(4095) As Byte

Dim iAR As IAsyncResult

iAR = PS.BeginRead(by Request, 0, UBound(byReques t) + 1, AddressOf
ASyncFileCallBa ckRead, byRequest)

End Sub

Private Sub ASyncFileCallBa ckRead(ByVal iAR As IAsyncResult)

Dim EnASCII As New System.Text.ASC IIEncoding()

Dim EnUNI As New System.Text.Uni codeEncoding()

Dim byteCount As Integer

Dim recData As String

'get the data passed in parameter of iAR

Dim recReq() As Byte = CType(iAR.Async State, Byte())

byteCount = PS.EndRead(iAR) 'get number of bytes read

If byteCount > 0 Then

recData = EnASCII.GetStri ng(recReq, 0, byteCount)
End Sub
"Jon Skeet [C# MVP]" <sk***@pobox.co m> wrote in message
news:MP******** *************** *@msnews.micros oft.com...

Lou <lo********@com cast.net> wrote:

I can't get it to work. Please help...
-louie
<snikp>

byte[] byRequest=new byte[4095];

iAR=myStream.Be ginRead(byReque st,0,4096,ASync FileCallBackRea d(iAR),myStream )
That's a bad start to begin with - you've asked it to read up to 4096
bytes, but only allocated 4095.

public void ASyncFileCallBa ckRead(IAsyncRe sult iAR)

{

System.Text.ASC IIEncoding EnAscii;
System.Text.ASC IIEncoding EnUNI;

You're declaring these variables, but never setting their values.

int byteCount;

string recData;

byte recReq[]=new byte[(Convert.ToByte (iAR.AsyncState )];

Why are you trying to convert iAR.AsyncState to a byte, and why are you
creating a new byte array?

I would expect you to pass byRequest as your state, rather than the
stream (as you apparently have a reference to the stream elsewhere - it
might well be a good idea to put *both* in the state, as a separate
type), and then just cast it back to a byte array. As it is, you're
completely ignoring whatever you've actually read.

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

[Jon Skeet [C# MVP]]

Lou <lo********@com cast.net> wrote:

I have the code in vb >Net and need to convert it to C#
It works great in VB .Net????

Well, it looks like the VB code *mostly* has the changes I was talking
about. I'd suggest just using the Encoding.ASCII property to get an
ASCIIEncoding instance rather than creating a new one, but the salient
points are:

o byRequest is passed instead of myStream as the parameter
o It's casting AsyncState to a byte array, not creating a *new* one
using Convert.ToByte as the length

Note that the VB line "Dim byRequest(4095) As Byte" is equivalent to
the C#

byte[] byRequest = new byte[4096]; as far as I know.

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

[Lou]

So why doesn't this work, I'm very confused...

IAsyncResult iAR;

byte[] byRequest=new byte[4095];

iAR=myStream.Be ginRead(byReque st,0,4095, ASyncFileCallBa ckRead,byReques t);

"Jon Skeet [C# MVP]" <sk***@pobox.co m> wrote in message
news:MP******** *************** *@msnews.micros oft.com...

Lou <lo********@com cast.net> wrote:

I have the code in vb >Net and need to convert it to C#
It works great in VB .Net????

Well, it looks like the VB code *mostly* has the changes I was talking
about. I'd suggest just using the Encoding.ASCII property to get an
ASCIIEncoding instance rather than creating a new one, but the salient
points are:

o byRequest is passed instead of myStream as the parameter
o It's casting AsyncState to a byte array, not creating a *new* one
using Convert.ToByte as the length

Note that the VB line "Dim byRequest(4095) As Byte" is equivalent to
the C#

byte[] byRequest = new byte[4096]; as far as I know.

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

[Jon Skeet [C# MVP]]

Lou <lo********@com cast.net> wrote:

So why doesn't this work, I'm very confused...

IAsyncResult iAR;

byte[] byRequest=new byte[4095];

iAR=myStream.Be ginRead(byReque st,0,4095, ASyncFileCallBa ckRead,byReques t);

That should work fine - what makes you think it doesn't?

(Note that unless you're actually going to use the returned
IAsyncResult, you don't need to store it in a variable anywhere.)

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

[Lou]

First off thank you for being patient as I am new to C#..

here is the erroe message,

C:\Documents and Settings\LGarvi n.PINNACLE\My Documents\Visua l Studio
Projects\Window sApplication13\ DekoAutomation. cs(160): No overload for method
'ASyncFileCallB ackRead' takes '0' arguments

Am I supposed to use a delegate(which are new to me) as a parameter
for the "myStream.Begin Read" to point to my callback function
"AsyncFileCallB ackread"

Thanks..
-Lou

//start an asyncronys read

//System.AsyncCal lback

IAsyncResult iAR;
byte[] byRequest=new byte[4095];

iAR=myStream.Be ginRead(byReque st,0,4095,ASync FileCallBackRea d(),byRequest);

public void ASyncFileCallBa ckRead(IAsyncRe sult iAR)

{

/*

System.Text.ASC IIEncoding EnAscii;

System.Text.ASC IIEncoding EnUNI;

int byteCount;

string recData;

//byte recReq[];
//byte[] byRequest=new byte[4095];

byte recReq[]=new byte[(Convert.ToByte (iAR.AsyncState )];

byteCount=myStr eam.EndRead(iAR );
recData = EnAscii.GetStri ng(recReq,0,byt eCount);

*/



}

"Jon Skeet [C# MVP]" <sk***@pobox.co m> wrote in message
news:MP******** *************** *@msnews.micros oft.com...

Lou <lo********@com cast.net> wrote:

So why doesn't this work, I'm very confused...

IAsyncResult iAR;

byte[] byRequest=new byte[4095];

iAR=myStream.Be ginRead(byReque st,0,4095,

ASyncFileCallBa ckRead,byReques t);
That should work fine - what makes you think it doesn't?

(Note that unless you're actually going to use the returned
IAsyncResult, you don't need to store it in a variable anywhere.)

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

[Jon Skeet [C# MVP]]

Lou <lo********@com cast.net> wrote:

First off thank you for being patient as I am new to C#..

here is the erroe message,

C:\Documents and Settings\LGarvi n.PINNACLE\My Documents\Visua l Studio
Projects\Window sApplication13\ DekoAutomation. cs(160): No overload for method
'ASyncFileCallB ackRead' takes '0' arguments

Am I supposed to use a delegate(which are new to me) as a parameter
for the "myStream.Begin Read" to point to my callback function
"AsyncFileCallB ackread"

Ah - sorry, didn't spot that previously. It should be:

myStream.BeginR ead (byRequest, 0, 4095,
new AsyncCallback (ASyncFileCallB ackRead),
byRequest);

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

[Lou]

I still get errors??

C:\Documents and Settings\LGarvi n.PINNACLE\My Documents\Visua l Studio
Projects\Window sApplication13\ DekoAutomation. cs(154): The best overloaded
method match for 'System.IO.Stre am.BeginRead(by te[], int, int,
System.AsyncCal lback, object)' has some invalid arguments
C:\Documents and Settings\LGarvi n.PINNACLE\My Documents\Visua l Studio
Projects\Window sApplication13\ DekoAutomation. cs(155): Argument '4': cannot
convert from 'WindowsApplica tion13.AsyncCal lback' to 'System.AsyncCa llback'

"Jon Skeet [C# MVP]" <sk***@pobox.co m> wrote in message
news:MP******** *************** *@msnews.micros oft.com...

Lou <lo********@com cast.net> wrote:

First off thank you for being patient as I am new to C#..

here is the erroe message,

C:\Documents and Settings\LGarvi n.PINNACLE\My Documents\Visua l Studio
Projects\Window sApplication13\ DekoAutomation. cs(160): No overload for method 'ASyncFileCallB ackRead' takes '0' arguments

Am I supposed to use a delegate(which are new to me) as a parameter
for the "myStream.Begin Read" to point to my callback function
"AsyncFileCallB ackread"

Ah - sorry, didn't spot that previously. It should be:

myStream.BeginR ead (byRequest, 0, 4095,
new AsyncCallback (ASyncFileCallB ackRead),
byRequest);

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