ListBox - SaveRows/LoadRows

sinner · **Joined:** Sat May 27, 2006 3:27 pm **Posts:** 480

Hello
I am going to show you a simple way how to load and save your listbox content to a data file.

Hope this helps

1. Make a Module with two methods one LoadData the other SaveData
2. Call the methods in a windows Open/Close event

Sub LoadData( L As ListBox )
  Dim Stream As BinaryStream
  Dim Count1,Count2,i,x As Integer
  Dim f As folderitem= GetFolderItem("C:\DataFile", FolderItem.PathTypeShell )
  If f.Exists Then
    If f = Nil Then Exit
    Stream = f.OpenAsBinaryFile(False)
    Count1 = Stream.ReadLong
    Count2 = Stream.ReadLong
    For i = 0 To Count1-1
      L.AddRow Stream.ReadPString
      For x = 1 To Count2-1
        L.Cell( i , x ) = Stream.ReadPString
      Next
    Next
    Stream.Close
  End
End Sub

Sub SaveData( L As ListBox )
  Dim i,x As integer
  Dim Stream As BinaryStream
  Dim f As FolderItem = New FolderItem( "C:\DataFile" , FolderItem.PathTypeShell )
  if f <> NIL Then
    Stream=f.CreateBinaryFile(".data")
    Stream.WriteLong L.ListCount
    Stream.WriteLong L.ColumnCount
    For i = 0 To L.ListCount-1
      For x = 0 To L.ColumnCount-1
        Stream.WritePString L.Cell( i , x )
      Next
    Next
    Stream.Close
  End
End Sub

Call it like this in the Windows Open/Close

Sub Window Open()
  Call LoadData( MyListBox1 )
End Sub

Sub Window Close()
  Call SaveData( MyListBox1 )
End Sub

classone · **Joined:** Mon Aug 14, 2006 9:33 pm **Posts:** 1774

If f.Exists Then
  If f = Nil Then Exit

This is backwards. You need to check for f = Nil BEFORE calling f.exists. If f is = nil, then your program has crashed before you get to the line "if f = Nil"

Stream = f.OpenAsBinaryFile(False)

This method is deprecated. The correct call is

Stream = binaryStreamOpen(f)

You should also check for
Stream <> Nil after the above call. It is a definite possibility that the stream can be Nil or encounter an I/O exception which will also cause your code to crash.

npalardy · **Posted:** Tue Jan 24, 2012 2:07 pm

[quote="sinner"]
L.AddRow Stream.ReadPString

The use of PString limits you to 255 characters of data

Avoiding that use and making the write write a int32 that is the count then the bytes would let you put as much data as you want
Also you probably need to know the encoding of the data you write & read

I've adjusted things as suggested (but this is entirely written in the forum so it's not tested)
But it should give you the idea

Sub SaveData( L As ListBox )
  Dim i,x As integer
  Dim Stream As BinaryStream
  Dim f As FolderItem = New FolderItem( "C:\DataFile" , FolderItem.PathTypeShell )
  if f <> NIL Then
    Stream=f.CreateBinaryFile(".data")
    Stream.WriteLong L.ListCount
    Stream.WriteLong L.ColumnCount
    For i = 0 To L.ListCount-1
      For x = 0 To L.ColumnCount-1
        dim data as string = ConvertEncoding( L.Cell( i , x ), Encodings.UTF8 )
        Stream.WriteInt32 lenB(data) // yes LenB as you need to know how many bytes you write
        Stream.Write data
      Next
    Next
    Stream.Close
  End
End Sub

Sub LoadData( L As ListBox )
  Dim Stream As BinaryStream
  Dim Count1,Count2,i,x As Integer
  Dim f As folderitem= GetFolderItem("C:\DataFile", FolderItem.PathTypeShell )
  If f.Exists Then
    If f = Nil Then Exit
    Stream = f.OpenAsBinaryFile(False)
    Count1 = Stream.ReadLong
    Count2 = Stream.ReadLong
    For i = 0 To Count1-1
      L.AddRow Stream.ReadPString
      For x = 1 To Count2-1
        dim readLen as Int32 = Stream.ReadInt32
        L.Cell( i , x ) = Stream.Read( readLen, Encodings.UTF8 )
      Next
    Next
    Stream.Close
  End
End Sub

The other thing you might want to do is pass in the folderitem to read from / write to as a parameter

sinner · **Joined:** Sat May 27, 2006 3:27 pm **Posts:** 480

I would also like to add this to this to this topic!

This is the most effective way i had found to save passwords & names to multiple columns , rows in a listbox without no hazel!

1. Make a new global method in a module an add the following code

Sub SaveLoadListbox( L As ListBox , Type As String )
  Dim f As folderitem
  Dim Stream As BinaryStream
  Dim Count1,Count2,i,x As Integer
  
  Select Case Type
    
  Case "Save"
    f= New FolderItem( "C:\DataFile")
    If f <> NIL Then
      Stream=f.CreateBinaryFile(".data")
      Stream.WriteLong L.ListCount
      Stream.WriteLong L.ColumnCount
      For i =0 To L.ListCount-1
        For x=0 To L.ColumnCount-1
          Stream.WritePString L.Cell(i,x)
        Next
      Next
      Stream.Close
    End
    
  Case "Load"
    f= GetFolderItem("C:\DataFile")
    If f <> NIL AND f.Exists Then
      Stream=f.OpenAsBinaryFile(False)
      Count1=Stream.ReadLong
      Count2=Stream.ReadLong
      If Count1 = 0 Then Return
      For i =0 To Count1-1
        L.AddRow Stream.ReadPString
        For x=1 To Count2-1
          L.Cell(i,x)=Stream.ReadPString
        Next
      Next
      Stream.Close
    End
  End Select
End Sub

2. Call it like this in a pushbutton or a listbox's open close event

'Save
Call SaveLoadListbox( listbox1, "Save" )
'Load
Call SaveLoadListbox( listbox1, "Load" )

Simple as that hope this helps

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ListBox - SaveRows/LoadRows