asked on

Progess bar in a file loading process

VB6:

Hello experts. I posted a question about loading big files. Here's another related one, which I choose to make its own question of.

I'm making a program which loads (sometimes) big textfiles into a textbox. Now I want to add a progressbar to the form, to make users feel better when loading big files.

The question is: How can add a progressbar to the file loading? That is, what parameter should the bar be connected to, and what is the maximum value?

Here's the code I use for importing the files:

CommonDialog1.ShowOpen
sFile = CommonDialog1.FileName
If sFile <> "" Then
iFn = FreeFile
Open sFile For Input As #iFn
Do While Not EOF(iFn)
Line Input #iFn, sLine
txtInput = txtInput & sLine & vbCrLf
Loop
Close #iFn
End If

AzraSound

if youre reading the lines in then all you need is to find out how many lines you have and divide it by how many you have read in thus far and get ther percentage complete to display in a progress bar. This code will tell you how many lines are in your file:

Function Count_Lines_In_File (ByVal strFilePath As String) As Integer
'delcare variables
Dim fileFile As Integer
Dim intLinesReadCount As Integer
intLinesReadCount = 0
'open file
fileFile = FreeFile

If (File_Exists(strFilePath)) Then
Open strFilePath For Input As fileFile
Else
'file doesn't exist
MsgBox "File: " & strFilePath & " hasn't been downloaded yet. Preprocessing is being aborted.", MB_OK, "File Does Not Exist"
Count_Lines_In_File = -1
Exit Function
End If
'loop through file
Dim strBuffer As String

Do While Not EOF(fileFile)
'read line
Input #fileFile, strBuffer
'update count
intLinesReadCount = intLinesReadCount + 1
Loop
'close file
Close fileFile
'return value
Count_Lines_In_File = intLinesReadCount
End Function

ASKER CERTIFIED SOLUTION

Éric Moreau

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mark2150

If you pull the entire file into the text box in one go you'll not be able to show a progress bar as you're only performing one INPUT statement and all of delay is occurring there.

Me, I'd opt for one big file pull and just pop a "Please wait, loading". Message while things run.

M

liljegren

ASKER

I was afraid of something like that too, mark2150, but fortunately you are wrong in this case. :-) emoreau's solution was the best answer I could get. Thank you all.

wsh2

Emoreau:
ProgressBar1.Value = Len(txtInput)
...
ProgressBar1.Value = Len(txtInput) _
+ ProgressBar1.Value
...
<smile> and a <wink>

mark2150

Doing it as one big load will be faster than doing a series of Line Input statements, esp. with a *big* file. For me, I'd rather have a static message displayed for a shorter period of time than a dynamic message displayed for a longer time.

Also, be sure to make the textbox.visible = false to keep the system from attempting to redraw the box as the data comes in. This too, will greatly slow the process down.

Since the two approaches are easy to code, why not write it both ways and *time* them loading the same large file. I think you may be surprised at the time difference.

M