Class for converting & formatting bytes, kilobytes, megabytes, gigabytes, etc.

by doug 14. May 2009 04:14

I'm working on an application that reads files from user selected folders and displays the names and file sizes in a grid. I want the file sizes to be formatted appropriate to their size. For example if a file is 50 bytes in size, it should say "50 B." If it's 200,000 bytes, it should be displayed as "195.3 KB." If it's 2,000,000 bytes, it should be displayed as "1.9 MB."

So I created the class displayed below. Instantiate it by passing in the number you want to convert and identifying what unit that number is in. Then if you know ahead of time what unit you want to convert that number to, call the relevant property. For example if you want to output in Megabytes, call the Megabytes() property. Or, as in my case, if you want it to automatically determine the best unit to output as, call the AutoUnit() property.

Here's an example of how you could use it:

Dim Label1 As New Label

Dim myFileInfo As New System.IO.FileInfo("c:\testfile.jpg")

Dim myUnitConvert As New _

cDataUnitConversions(cDataUnitConversions.DataUnits.Bytes, _

myFileInfo.Length)

Label1.Text = myUnitConvert.AutoUnit

The FileInfo class is used to get the attributes of the file "testfile.jpg." Then the cDataUnitConverstions class is instantiated, passing in the length of the test file and identifying that length as being in Bytes. From there the Label1.Text property is set to be equal to the AutoUnit value, which would be something like "345.12 KB" depending on how big the test file really is.

Below is the class. Some next steps would include expanding it to output as strings or numeric data types, toggle on or off the unit labels in the string (like "50 MB" vs. "50"), and more. But hopefully this will get you going in the right direction and you can customize as you see fit.

Public Class cDataUnitConversions

#Region " Enums, Global Variables and Constants "

Public Enum DataUnits

Bits

Bytes

Kilobytes

Megabytes

Gigabytes

Terabytes

End Enum

Dim _inputValue As Double

Dim _inputUnit As DataUnits

Const BitsInByte As Double = 8

Const BytesInKilobyte As Double = 1024

Const BytesInMegabyte As Double = 1048576

Const BytesInGigabyte As Double = 1073741824

Const BytesInTerabyte As Double = 1099511627776

#End Region

#Region " Properties "

Public ReadOnly Property Bits() As String

Get

Return String.Format("{0:N}", _

InputAsBytes() * BitsInByte) & " b"

End Get

End Property

Public ReadOnly Property Bytes() As String

Get

Return String.Format("{0:N}", InputAsBytes()) & " B"

End Get

End Property

Public ReadOnly Property Kilobytes() As String

Get

Return String.Format("{0:N}", _

InputAsBytes() / BytesInKilobyte) & " KB"

End Get

End Property

Public ReadOnly Property Megabytes() As String

Get

Return String.Format("{0:N}", _

InputAsBytes() / BytesInMegabyte) & " MB"

End Get

End Property

Public ReadOnly Property Gigabytes() As String

Get

Return String.Format("{0:N}", _

InputAsBytes() / BytesInGigabyte) & " GB"

End Get

End Property

Public ReadOnly Property Terabytes() As String

Get

Return String.Format("{0:N}", _

InputAsBytes() / BytesInTerabyte) & " TB"

End Get

End Property

Public ReadOnly Property AutoUnit() As String

Get

Return GetAutoUnit()

End Get

End Property

#End Region

#Region " Public Methods "

Public Sub New(ByVal inputUnit As DataUnits, _

ByVal inputValue As Double)

_inputValue = inputValue

_inputUnit = inputUnit

End Sub

#End Region

#Region " Private Methods "

Private Function GetAutoUnit() As String

Dim Output As String

Dim InputBytes As Double = InputAsBytes()

Select Case InputBytes

Case Is < BytesInKilobyte