Difficulty reading and writing binary files - vb.net

Question

My code works on my 64-bit machine but I encounter the following error (occasionally the code works fine however) when running it on a 32-bit machine:
InvalidCastException was unhandled
The next few lines provide my code:
To write to the binary file:
Dim writeStream = New FileStream(path, FileMode.Open)
Dim BinReader As BinaryReader
next_byte = Len(CStr(time)) + Len("EndOfHeader") + 16 + 2
first_time = True
BinWriter = New BinaryWriter(writeStream)
For i = 0 To Form1.signals.Length - 1
If IsNothing(Form1.signals(i)) = False Then
'once for each test
BinWriter.Write(Int(Form1.signals(i).picodata.GetLength(0) - 1)) 'n for each signal in test
BinWriter.Write(Form1.signals(i).picodata(1, 0) - Form1.signals(i).picodata(0, 0)) 'timestep
BinWriter.Write(next_byte) 'position of start of test
BinWriter.Write(CStr(time))
Exit For
End If
Next
BinWriter.Write("EndOfHeader")
For i = 0 To Form1.signals.Length - 1
If IsNothing(Form1.signals(i)) = False Then
BinWriter.Write(i)
For j = 1 To Form1.signals(i).picodata.GetLength(0) - 1
BinWriter.Write(Form1.signals(i).picodata(j, 1))
Next
End If
Next
BinWriter.Close()
To read in:
Dim readstream As FileStream
Dim end_test As Integer
Dim Index As Integer
Dim BinReader As BinaryReader
Dim end_head as Boolean=false
Dim count as integer=0
selected_test=0
ReadStream = New FileStream(readFileName, FileMode.Open)
BinReader = New BinaryReader(ReadStream)
'read header
While end_head = False
Try
pos_old = ReadStream.Position
try_string = BinReader.ReadString
If try_string = "EndOfHeader" Then
Exit While
Else
ReadStream.Position = pos_old
End If
Catch ex As Exception
ReadStream.Position = pos_old
End Try
'this approach allows for flexibility
number_arr(count) = BinReader.ReadInt32
TimeStep_arr(count) = BinReader.ReadDouble
position_arr(count) = BinReader.ReadInt32
time_arr(count) = CDate(BinReader.ReadString)
count += 1
End While
'read in data
While readstream.Position <> read_stream.length
ReDim PicoData(number_arr(selected_test), 1)
Index = BinReader.ReadInt32
n = number_arr(selected_test)
For i = 1 To n
PicoData(i, 1) = BinReader.ReadDouble
PicoData(i, 0) = TimeStep_arr(selected_test) * i
Next
ReDim TimeShort(Int(n / 20))
ReDim FiltVoltsShort(Int(n / 20))
ReDim FiltVelShort(Int(n / 20))
ReDim RawVoltsShort(Int(n / 20))
'generate new reading here
Call FourierFilter(PicoData, 0)
signals(Index) = New reading(Index, TimeShort, RawVoltsShort, FiltVelShort, FiltVoltsShort, Points_Store(ii, 2), Points_Store(ii, 1), DataChart, VelocityChart, SelectedTimeBox, SelectedVelocityBox, True, PicoData)
End While
BinReader.Close()
readstream.Close()
The date occasionally is not read in correctly. I will get some character + the date I want. Parts of my code have been cut out (since the program is pretty huge) but hopefully what I have sent will make some sense. Thanks

Answer 1

Your first step should be to find a simple-as-possible reproducible test case where you can make it fail every time. Then it will be much easier to identify the source of the problem.
Code like this might help you narrow down how BinaryWriter encodes strings on different platforms.
Dim content As String = New String("!"c, 255)
Using outStream As New System.IO.MemoryStream()
Using bw As New System.IO.BinaryWriter(outStream)
bw.Write(content)
bw.Flush()
outStream.Flush()
Console.WriteLine("I am a " & If(Environment.Is64BitProcess, "64", "32") & _
"-bit process")
Console.WriteLine("I generated a string of {0} characters into a stream " & _
"of {1} bytes", content.Length, outStream.Length)
End Using
End Using