Filesize Conversion

Dayekh

Hi all, I'm finding it hard to work with file conversion in VB.Net. I already have the filesize in Bytes, but I need to display it as KB in a repeater. The examples on google are too complex for what I need. Any help is appreciated. Thanks.

DaveAuld

KB = Bytes/1024, em, what else do you want to know? what exactly are you stuck with.

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Dayekh

I would like to know if there is function in built that converts filesizes automatically. For instance if there is a file that is 1234 bytes, it will be represented as 1.23 KB, or if we have a file that is 1234567, it will be represented as 1.23 MB. Or anything along these lines.

Luc Pattyn

that is a dangerous idea; all files with sizes less than 1024B will show as 0KB, giving you the impression they are empty. Much better is rounding up like this:

sizeInKiloBytes=(sizeInBytes+1023)/1024;

which only shows zero when it really is zero. :)

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Luc Pattyn

No, there is not. :)

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Dayekh

I found to format it, but I'm still getting errors.. I will post update this when I work it out.

DaveAuld

I was being overly simplistic to try and find out what exactly the problem is........i would hope that anybody who is working in IT knows the relationships between bits bytes k, m, g, t.....and on and on. but yes agree with your point, i.e. never show zero unless it is actually zero.

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DaveAuld

I have never tried it but see here for StrFormatByteSize; http://www.pinvoke.net/default.aspx/shlwapi/StrFormatByteSize.html[^]

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Dayekh

Thank you all for your input. I have finally written a function to do exactly what I need to be done. Please look at the code below and benefit from it if you wish:

    Public Function BytesFormatting(ByVal Bytes As Integer) As String

        Dim FormattedFileSize As Double

        If Bytes < 1024 Then
            ''code to format fsize as KB
            Dim dblFormatted As Double
            dblFormatted = Bytes
            FormattedFileSize = Format(dblFormatted, "###,###.00") + "KB"

        ElseIf (Bytes > 1024 And Bytes < 1048576) Then
            ''code to format fsize as KB
            Dim dblFormatted As Double
            dblFormatted = (Bytes + 1023) / 1024
            FormattedFileSize = Format(dblFormatted, "###,###.00") + "KB"

        ElseIf Bytes > 1048576 Then
            ''code to format fsize as MB
            Dim dblFormatted As Double
            dblFormatted = (Bytes / 1024) / 1024
            FormattedFileSize = Format(dblFormatted, "###,###,###.00") + "MB"
        End If

        Return FormattedFileSize.ToString
    End Function

The Man from U N C L E

Hate to be the bearer of bad news but you have a typo in your first if chunk.

Dayekh wrote:

If Bytes < 1024 Then ''code to format fsize as KB Dim dblFormatted As Double dblFormatted = Bytes FormattedFileSize = Format(dblFormatted, "###,###.00") + "KB"

Surely you mean bytes here rather than kilobytes, eg.

If Bytes < 1024 Then
''code to format fsize as B (bytes)
Dim dblFormatted As Double
dblFormatted = Bytes
FormattedFileSize = Format(dblFormatted, "###,###.00") + "B"

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Dayekh

Not at all, that was intentional. However I should have been clearer. The reason that code block refers to formatting in KiloBytes is because I would like any file that is less than 1024 to be displayed as KB as well. For example a file that is 643 Bytes big will appear as 0.64KB Cheers.

Lost User

daveauld wrote:

i would hope that anybody who is working in IT knows the relationships between bits bytes k, m, g, t.....and on and on.

Never assume this. I once heard one of our IT help desk reps ask a colleague "What exactly is hexadecimal?".

It's time for a new signature.

scottgp

I worked with a woman who was supposedly in IT for at least 10 years, who was previously an Oracle instructor, and asked me how to convert K to MB. Scary. Scott

riced

What if file is exactly 1024 or 1048576 bytes? Not likely but not impossible, I can generate one of either size with ease. :)

Regards David R --------------------------------------------------------------- "Every program eventually becomes rococo, and then rubble." - Alan Perlis The only valid measurement of code quality: WTFs/minute.

Luc Pattyn

right. and doesn't Dim FormattedFileSize As Double deserve some attention too? :)

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riced

Yup. But I guess he has Option Strict Off either intentionally or by default. That allows it to compile. But there's even worse when you look at it more closely e.g. a file of 1023 bytes returns 1,023.00KB. :-D He did say it was working so I suppose he tested it. :laugh:

Regards David R --------------------------------------------------------------- "Every program eventually becomes rococo, and then rubble." - Alan Perlis The only valid measurement of code quality: WTFs/minute.

Luc Pattyn

I have finally written a function to do exactly what I need to be done. Please look at the code below and benefit from it if you wish I think he meant: no need for me to test it, just publish and wait a while. Not sure it will still do what "needs to be done" when we are through... :)

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riced

I decide to benefit and wrote something that does work. :-D Try plugging yours into the Main and see what happens. :)

Module Module1
Sub Main()
Dim s As String = ""
Console.WriteLine("--- Kilobytes ---")
s = FormattedFileSize(1023)
Console.WriteLine("1023 > " & s)
s = FormattedFileSize(1024)
Console.WriteLine("1024 > " & s)
s = FormattedFileSize(1025)
Console.WriteLine("1025 > " & s)

  Console.WriteLine("--- Megabytes ---")
  s = FormattedFileSize(1048575)
  Console.WriteLine("1048575 > " & s)
  s = FormattedFileSize(1048576)
  Console.WriteLine("1048576 > " & s)
  s = FormattedFileSize(1048577)
  Console.WriteLine("1048577 > " & s)
  s = FormattedFileSize(1048576 \* 2)
  Console.WriteLine("1048577 \* 2 > " & s)

  Console.WriteLine("--- Gigabytes ---")
  s = FormattedFileSize(1048576 \* 1024)
  Console.WriteLine("1048576 \* 1024 > " & s)

  Console.ReadLine()

End Sub

Public Function FormattedFileSize(ByVal sizeInBytes As Long) As String
Dim suffix() As String = New String() {"", "KB", "MB", "GB", "XX"}
Dim retVal As String = "Oops"
Dim units As Double = sizeInBytes
Dim index As Integer = 0
Do
units = units / 1024.0
index += 1
Loop While units >= 1024.0

  retVal = Format(units, "###,###,##0.000") + suffix(index)
  Return retVal

End Function

End Module

PS you just need to change the name of the function calls e.g. use s = BytesFormatting(1024)

Regards David R --------------------------------------------------------------- "Every program eventually becomes rococo, and then rubble." - Alan Perlis The only valid measurement of code quality: WTFs/minute.

Dayekh

Thank you all for your input! I certainly was happy that this issue had a lot of interest. "i would hope that anybody who is working in IT knows the relationships between bits bytes k, m, g, t.....and on and on." -- knowing the relationship between bytes, KB, MB, etc.. was irrelevant as I was asking if there was a class/method that automatically did the conversions in VB.Net. And yes, I know the relationship between them :P "I think he meant: no need for me to test it, just publish and wait a while." -- Yea I'm sure all programmers are perfect testers of THEIR own code. I did some testing, but it obviously wasn't good enough. I suppose that's what learning is.. no? "What if file is exactly 1024 or 1048576 bytes?" -- Good point! I was swamped with work that I overlooked that fault. Thank you. "But there's even worse when you look at it more closely e.g. a file of 1023 bytes returns 1,023.00KB." -- Another good point. I need to address all eventualities more closely! "I decide to benefit and wrote something that does work." -- Thank you. I will work through that code. Thanks again all! This made my day.

Luc Pattyn

You have some IndexOutOfRange problems... As a little VB exercise, here an alternative, spanning a larger range of values; the result is slightly different, notation is float or integer as appropriate:

Private Sub Button1\_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    Dim pow As Long = 1
    For i = 0 To 63
        Dim fraction As Long = pow \\ 32
        If fraction < 1 Then fraction = 1
        test(-pow)
        test(pow - fraction)
        test(pow)
        test(pow + fraction)
        If pow >= &H4000000000000000 Then Exit For
        pow = 2 \* pow
    Next
End Sub

Public Sub test(ByVal value As Long)
    Dim s As String
    s = FormattedFileSize(value)
    Console.WriteLine(value.ToString().PadLeft(20) & " = " & value.ToString("X16") & " = " & s & "B")
End Sub

Public Function FormattedFileSize(ByVal sizeInBytes As Long) As String
    Dim negative As Boolean = False
    Dim result As String
    Dim value As Long = sizeInBytes
    Dim remainder As Long = 0
    Dim suffixIndex As Integer
    If value < 0 Then
        negative = True
        value = -value
    End If
    For suffixIndex = 0 To 20
        If value <= 1023 Then Exit For
        remainder = value Mod 1024
        value = value \\ 1024
    Next
    If remainder > 0 Then
        Dim d As Double = value + remainder / 1024
        result = d.ToString("F3")
    Else
        result = value.ToString()
    End If
    If suffixIndex > 0 Then result = result & " KMGTPEZY"(suffixIndex)
    If negative Then result = "-" & result
    Return result
End Function

Homework: find and fix the value(s) that still fail. :)

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