BinaryReader.PeekChar ArgumentException: Conversion Buffer Overflow

Dim buffer(1024) As Byte BTW: You have an array of 1025 bytes, as the 1024 is the high index, the low
index is 0.

Hope this helps
Jay

"Tim" <ti********@yahoo.com> wrote in message
news:%2****************@tk2msftngp13.phx.gbl... Hi,

I'm experiencing some problem with the following code:

st = File.Open(sFilename, FileMode.Open, FileAccess.ReadWrite)
br = New BinaryReader(st)

Do Until br.PeekChar = -1
Dim buffer() As Byte = br.ReadBytes(1024)
...
Loop

Basically, PeekChar would sometimes cause the System.ArgumentException in
mscorlib.dll with the message "Conversion buffer overflow." However, when I examine the value after inserting breakpoints, br.PeekChar returns normal
values without error. Furthermore, the number of bytes read before the
error occurs is always the same, assuming I am using the same file.

This problem disappears after I change the code to the following:

Dim len As Integer = 1

Do Until len = 0
Dim buffer(1024) As Byte
len = br.Read(buffer, 0, 1024)
...
Loop

This makes me believe that the problem _is_ indeed caused by PeekChar.

I've tried searching for people expericing similar problems online, but to
no avail. Anyone has any idea?

Thanks.
Tim

Jay,

The exceptions are occurring in the middle of the file (almost never at the end), so I'm going to assume that sizeof(char) is not the issue.

I guess I was mislead by the book "Programming Microsoft Visual Basic .NET
Core Reference" by Francesco Balena, in which the following example is used:
Dim st2 as Stream = File.Open("c:\value.dat", FileMode.Open,
FileAccess.Read)
Dim br2 as New BinaryReader(st2)

Do Until br2.PeekChar = -1
Console.WriteLine(br2.ReadDouble)
Loop

br2.Close()
st2.Close()

But then again, since sizeof(double) % sizeof(char) == 0, I guess that's why it works.

Thanks a lot for the help. I'll go ahead and use the second version.
Tim