Hello All,
I have a very annoying little problem with VB .NET and was wondering if anyone could cast some light on it.
I am opening and reading a file using random access, I have defined the structure I am reading in. I can read the data in, but when I write out the data the final 40 bytes or so do not get updated until I close the file. This is annoying as I update the file as part of a design process and need to read the data after I have written it. the data consists of an array of 50 items, i can update the second last entry no problem but the majority of the data in the last entry is not filed to disk until the file is closed. Here is a cut down version of the code in a test example.
Public Class Form1
Dim filRanR As Short
Dim filRanW As Short
Dim filBinR As Short
Dim filBinW As Short
Dim modelfilename As String = "c:\conference\model1.fil"
Dim RecordSize As Integer = 2016
Public Structure StringIdx
<VBFixedString(4)> Public Label As String
<VBFixedString(4)> Public SubRef As String
Dim StringType As Integer
Dim NumPoints As Integer
<VBFixedArray(3)> Dim enBox() As Integer
Dim RecordNum As Integer
Dim Location As Integer
Public Sub Initialize()
ReDim enBox(3)
End Sub
End Structure
Private Structure stringIdxRec
<VBFixedArray(49)> Dim stringEntry() As StringIdx
Dim nextIdxRecNum As Integer
Dim nextFileRecNum As Integer
Dim fluff1 As Integer
Dim fluff2 As Integer
Public Sub Initialize()
Dim i0 As Integer
ReDim stringEntry(49)
For i0 = 0 To 49
ReDim stringEntry(i0).enBox(3)
Next
End Sub
End Structure
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim tempStringRec As New stringIdxRec
Dim t1 As New stringIdxRec
tempStringRec.Initialize()
t1.Initialize()
openRead()
openWrite()
FilePut(filRanW, t1, 1)
FileGet(filRanW, tempStringRec, 1)
tempStringRec.stringEntry(48).NumPoints = 1
tempStringRec.stringEntry(48).RecordNum = 1
tempStringRec.stringEntry(48).SubRef = "wwww"
tempStringRec.stringEntry(49).NumPoints = 5
tempStringRec.stringEntry(49).RecordNum = 5
tempStringRec.stringEntry(49).SubRef = "gggg"
tempStringRec.stringEntry(49).StringType = 777712
tempStringRec.stringEntry(49).enBox(0) = 10
tempStringRec.stringEntry(49).enBox(1) = 20
tempStringRec.stringEntry(49).enBox(2) = 30
tempStringRec.stringEntry(49).enBox(3) = 40
tempStringRec.fluff1 = 777
FilePut(filRanW, tempStringRec, 1)
FileGet(filRanR, t1, 1)
closeWrite()
closeRead()
End Sub
Public Function openRead() As Integer
Dim retval As Integer
On Error GoTo badopen
filRanR = FreeFile()
FileOpen(filRanR, modelfilename, OpenMode.Random, OpenAccess.Read, _
OpenShare.Shared, RecordSize)
filBinR = FreeFile()
FileOpen(filBinR, modelfilename, OpenMode.Binary, OpenAccess.Read, _
OpenShare.Shared)
badopen:
On Error GoTo 0
openRead = retval
End Function
Public Sub closeRead()
On Error Resume Next
FileClose(filRanR)
FileClose(filBinR)
filRanR = 0
filBinR = 0
On Error GoTo 0
End Sub
Public Function openWrite() As Integer
Dim retval As Integer
On Error GoTo badopen
filRanW = FreeFile()
FileOpen(filRanW, modelfilename, OpenMode.Random, , _
OpenShare.Shared, RecordSize)
filBinW = FreeFile()
FileOpen(filBinW, modelfilename, OpenMode.Binary, , OpenShare.Shared)
badopen:
On Error GoTo 0
openWrite = retval
End Function
Public Sub closeWrite()
On Error Resume Next
FileClose(filRanW)
FileClose(filBinW)
filRanW = 0
filBinW = 0
On Error GoTo 0
End Sub
End Class
The test example defines a form with a button, when the button is pressed a blank record is written to disk and then read back into a different variable. I then change a bunch of values and write the data back to disk. I then read the values back into a variable (t1). If execution is halted at this point and the variable t1 is inspected it can be seen that the info that should have been written out is not present. In fact the only way to fully update the record is to close the file which I do not want to do, yet. and yes I know some of the code is a little dodgy.
Any ideas would be greatly appreciated.
Kind Regards
Martin Duke.
