FileStream.Write doing odd things...

[andycee]

Hi,

I'm having FileStream.Write behave rather oddly.

The code below should take file a.txt and append it to file b.txt :

        Dim buffer As Byte()
        Dim bytesRead As Integer
        Dim fStreamIN As New FileStream("c:\a.txt", FileMode.Open, FileAccess.Read)
        Dim fStreamOUT As New FileStream("c:\b.txt", FileMode.Append, FileAccess.Write)
        ReDim buffer(fStreamIN.Length)
 
        bytesRead = fStreamIN.Read(buffer, 0, fStreamIN.Length)
        MsgBox("Read bytes:" + Str(bytesRead) + " Expected:" + Str(fStreamIN.Length))
        MsgBox("byte 1:" + Chr(buffer(0)) + vbCrLf + _
"byte 2:" + Chr(buffer(1)) + vbCrLf + _
"byte 3:" + Chr(buffer(2)) + vbCrLf)
        fStreamOUT.Write(buffer, 0, buffer.Length)
 
        fStreamOUT.Flush()
        fStreamIN.Close()
        fStreamOUT.Close()

I test with :

a.txt "abc"
b.txt "<This is the Orig>"

Now when I run this code, the characters in a.txt are read correctly to buffer, but the file b.txt contains :

"<This is the Orig>扡c"

What on earth is going on ???

cheers

[JonJacobs]

I'm having FileStream.Write behave rather oddly.

You need to flush and close then IN stream before you write to the OUT stream, otherwise you might not get everything you need into your buffer.

I modified your code accordingly, and it worked fine for me, when I made that change.

HTH

[Killer42]

I modified your code accordingly, and it worked fine for me, when I made that change.

Did you test whether the problem occurred before making the change?

[JonJacobs]

Did you test whether the problem occurred before making the change?

Failing to close the stream before using the buffer will have variable results, but it is definitely the source of the problem.

[Killer42]

Failing to close the stream before using the buffer will have variable results, but it is definitely the source of the problem.

Ok. I never use stream, just wanted to double-check we weren't overlooking something.

By the way, you wouldn't actually need to flush an input stream, would you? Unless the meaning of "flush" has changed in the last few years.

[JonJacobs]

Ok. I never use stream, just wanted to double-check we weren't overlooking something.

By the way, you wouldn't actually need to flush an input stream, would you? Unless the meaning of "flush" has changed in the last few years.

True enough. I flush everything, just in case, since I am new to VB, and I am paranoid. <g>

[Killer42]

True enough. I flush everything, just in case ...

Ok, thanks. Just wanted to check, in case I was just behind the times (as in so many things).