如何使用公共函数从字节返回KB、MB和GB

问题描述 投票：0回答：6

我正在编写一个返回文件大小（以 B、KB、MB、GB 为单位）的“函数”。

VB.Net 代码始终首先获取以字节为单位的大小，因此当文件大小（以字节为单位）小于 100 时，它返回 B，如果它 > 1000，则将其除以 1000，然后返回 KB。但是当它应该是 MB 时，我尝试除以 1000000，它返回的大小总是比应有的大 2 MB！？

有人可以告诉我我做错了什么吗！！

示例

我的文件大小是（15,570,550 字节）..即..（14.8 MB）

所以当我通过这个函数运行它时，它返回 16MB！

代码

Public Function GetFileSize(ByVal TheFile As String, _
                            Optional ByVal ShowSizeType As Boolean = False) As String
    If TheFile.Length = 0 Then Return ""
    If Not System.IO.File.Exists(TheFile) Then Return ""
    '---
    Dim TheSize As Integer = My.Computer.FileSystem.GetFileInfo(TheFile).Length
    Dim SizeType As String = ""
    '---
    If TheSize < 1000 Then
        SizeType = "B"
    Else
        If TheSize < 1000000000 Then
            If TheSize < 1000000 Then
                SizeType = "KB"
                TheSize = TheSize / 1000
            Else
                SizeType = "MB"
                TheSize = TheSize / 1000000
            End If
        Else
            SizeType = "GB"

        End If
    End If
    '---
    If ShowSizeType = True Then
        Return TheSize & SizeType
    Else
        Return TheSize
    End If
End Function
vb.net .net-4.0 unit-conversion
6个回答
14
投票

我会使用 select case 而不是 if。
并且始终从最大的尺寸开始。”我在 TB 停止，但在科西嘉岛，如果需要，您可以添加更多......”

我将 Dim TheSize As Integer 更改为“Dim TheSize As ULong ”，否则大数字不起作用。

还制作一个暗淡的“Dim DoubleBytes As Double”，您将在选择的情况下使用它。

首先将您拥有的字节与 case 进行比较，假设 mb“Case 1048576 到 1073741823”
因此，如果是这种情况，请将 TheSize 转换为双精度 "DoubleBytes = CDbl(TheSize / 1048576) 'MB “

然后在返回中使用 FormatNumber 来设置要在 后面显示的数字。 “数字 2 是将其设置为 . 后面的 2。比如 28.11 ，将其更改为 0，它将返回 28”也因为你知道它 mb 你会在返回中添加 & mb 。
“返回格式编号(DoubleBytes, 2) & “MB” ”

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    MsgBox(GetFileSize("E:\Software\TeamSpeak3-Client-win64-3.0.14.exe"))
End Sub

Dim DoubleBytes As Double

Public Function GetFileSize(ByVal TheFile As String) As String
    If TheFile.Length = 0 Then Return ""
    If Not System.IO.File.Exists(TheFile) Then Return ""
    '---
    Dim TheSize As ULong = My.Computer.FileSystem.GetFileInfo(TheFile).Length
    Dim SizeType As String = ""
    '---

    Try
        Select Case TheSize
            Case Is >= 1099511627776
                DoubleBytes = CDbl(TheSize / 1099511627776) 'TB
                Return FormatNumber(DoubleBytes, 2) & " TB"
            Case 1073741824 To 1099511627775
                DoubleBytes = CDbl(TheSize / 1073741824) 'GB
                Return FormatNumber(DoubleBytes, 2) & " GB"
            Case 1048576 To 1073741823
                DoubleBytes = CDbl(TheSize / 1048576) 'MB
                Return FormatNumber(DoubleBytes, 2) & " MB"
            Case 1024 To 1048575
                DoubleBytes = CDbl(TheSize / 1024) 'KB
                Return FormatNumber(DoubleBytes, 2) & " KB"
            Case 0 To 1023
                DoubleBytes = TheSize ' bytes
                Return FormatNumber(DoubleBytes, 2) & " bytes"
            Case Else
                Return ""
        End Select
    Catch
        Return ""
    End Try
End Function

我为它制作了一个dll。
然后我可以将它导入到我的项目中，每当我需要将字节数更改为其他“如 mb 等”时，我都可以调用它
FormatBytes(GetHDSizeF) "GetHDSizeF 是字节数"

Dim DoubleBytes As Double
Default Public Property FormatBytes(ByVal BytesCaller As ULong) As String
    Get
        Try
            Select Case BytesCaller
                Case Is >= 1099511627776
                    DoubleBytes = CDbl(BytesCaller / 1099511627776) 'TB
                    Return FormatNumber(DoubleBytes, 2) & " TB"
                Case 1073741824 To 1099511627775
                    DoubleBytes = CDbl(BytesCaller / 1073741824) 'GB
                    Return FormatNumber(DoubleBytes, 2) & " GB"
                Case 1048576 To 1073741823
                    DoubleBytes = CDbl(BytesCaller / 1048576) 'MB
                    Return FormatNumber(DoubleBytes, 2) & " MB"
                Case 1024 To 1048575
                    DoubleBytes = CDbl(BytesCaller / 1024) 'KB
                    Return FormatNumber(DoubleBytes, 2) & " KB"
                Case 0 To 1023
                    DoubleBytes = BytesCaller ' bytes
                    Return FormatNumber(DoubleBytes, 2) & " bytes"
                Case Else
                    Return ""
            End Select
        Catch
            Return ""
        End Try
    End Get
    Set(value As String)

    End Set
End Property

如果你不想制作 dll，你可以像这样使用普通函数。

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    MsgBox(FormatBytes(2000))
End Sub

Dim DoubleBytes As Double
Public Function FormatBytes(ByVal BytesCaller As ULong) As String

    Try
        Select Case BytesCaller
            Case Is >= 1099511627776
                DoubleBytes = CDbl(BytesCaller / 1099511627776) 'TB
                Return FormatNumber(DoubleBytes, 2) & " TB"
            Case 1073741824 To 1099511627775
                DoubleBytes = CDbl(BytesCaller / 1073741824) 'GB
                Return FormatNumber(DoubleBytes, 2) & " GB"
            Case 1048576 To 1073741823
                DoubleBytes = CDbl(BytesCaller / 1048576) 'MB
                Return FormatNumber(DoubleBytes, 2) & " MB"
            Case 1024 To 1048575
                DoubleBytes = CDbl(BytesCaller / 1024) 'KB
                Return FormatNumber(DoubleBytes, 2) & " KB"
            Case 0 To 1023
                DoubleBytes = BytesCaller ' bytes
                Return FormatNumber(DoubleBytes, 2) & " bytes"
            Case Else
                Return ""
        End Select
    Catch
        Return ""
    End Try

End Function
4
投票

您需要除以 1024，而不是 1000。1 KB 不是 1000 字节，而是 1024 字节。 1 MB 不是 1000 KB，而是 1024 KB，依此类推。

这里有一个很好的网站来解释这一切：http://pc.net/helpcenter/answers/why_1024_bytes

4
投票

这是我的做法，下面是我在 Microsoft Access 中使用的 VBA 函数，可以轻松转换为 VB 或 VBScript 等。

Public Function FormatFileSize(ByVal lngFileSize As Long) As String

  Dim x      As Integer:      x = 0
  Dim Suffix As String:  Suffix = ""
  Dim Result As Single:  Result = lngFileSize

  Do Until Int(Result) < 1000
     x = x + 1
     Result = Result / 1024
  Loop

  Result = Round(Result, 2)

  Select Case x
         Case 0
              Suffix = "Bytes"
         Case 1 'KiloBytes
              Suffix = "KB"
         Case 2 'MegaBytes
              Suffix = "MB"
         Case 3 'GigaBytes
              Suffix = "GB"
         Case 4 'TeraBytes
              Suffix = "TB"
         Case 5 'PetaBytes
              Suffix = "PB"
         Case 6 'ExaBytes
              Suffix = "EB"
         Case 7 'ZettaBytes
              Suffix = "ZB"
         Case 8 'YottaBytes
              Suffix = "YB"
         Case Else
              Suffix = "Too big to compute :)"
  End Select

  FormatFileSize = Format(Result, "#,##0.00") & " " & Suffix

End Function 'FormatFileSize
3
投票

当我试图解决这个问题时，这篇文章帮助了我学习 C#，我通常使用 VB。不管怎样，我想我会发布我的更新，以防有人愿意使用它。 它是在 VB 中进行的，因为我有一个有用的函数和子库，我用它来保存这些东西，而且我是在 VB 中开始的，而且懒得更改所有代码。它对我来说效果很好，所以我希望它能帮助别人。

Function ByteConv(Bytes As Double, Optional Style As Integer = 1) As String

    Dim count As Integer = 0
    Dim factor As Integer = 1024
    Dim Workingnum As Double = Bytes
    Dim Suffix() As String = {"Bytes", "Kb", "Mb", "Tb", "Pb", "Eb"} 'Dimention the string array upto Exobyte .. Cos why not?'

    If Style - 1 Then factor = 1000 Else factor = 1024  'This allows for Function to be used for Comms Calculations. I.e So it returns 100MB connection rather than 95.37'

    While Workingnum > factor And count < 5             'Basically keep dividing the Bytecount by the factor until the result reaches a whole number less that the factor itself'
        Workingnum = Workingnum / factor                ' '
        count = count + 1
    End While
    Return Workingnum.ToString("N") + Suffix(count)     ' Then return a string that includes the result and the applicable suffix.'
End Function
1
投票

这是我在评论中的意思的一个例子：

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click

    If OpenFileDialog1.ShowDialog() = Windows.Forms.DialogResult.OK Then
        Dim CalculatedSize As Decimal
        Dim TheSize As Long = Long.Parse(My.Computer.FileSystem.GetFileInfo(OpenFileDialog1.FileName).Length)
        Dim SizeType As String = "B"

        If TheSize < 1024 Then
            CalculatedSize = TheSize

        ElseIf TheSize > 1024 AndAlso TheSize < (1024 ^ 2) Then 'KB
            CalculatedSize = Math.Round((TheSize / 1024), 2)
            SizeType = "KB"

        ElseIf TheSize > (1024 ^ 2) AndAlso TheSize < (1024 ^ 3) Then 'MB
            CalculatedSize = Math.Round((TheSize / (1024 ^ 2)), 2)
            SizeType = "MB"

        ElseIf TheSize > (1024 ^ 3) AndAlso TheSize < (1024 ^ 4) Then 'GB
            CalculatedSize = Math.Round((TheSize / (1024 ^ 3)), 2)
            SizeType = "GB"

        ElseIf TheSize > (1024 ^ 4) Then 'TB
            CalculatedSize = Math.Round((TheSize / (1024 ^ 4)), 2)
            SizeType = "TB"

        End If

        MessageBox.Show("File size is: " & CalculatedSize.ToString & " " & SizeType, "File size", MessageBoxButtons.OK, MessageBoxIcon.Information)
    End If
End Sub

结果：

File Sizes example

0
投票
  Public Function GetDirSize(RootFolder As String) As Long
        Dim FolderInfo = New IO.DirectoryInfo(RootFolder)
        For Each File In FolderInfo.GetFiles : TotalSize += File.Length
        Next
        For Each SubFolderInfo In FolderInfo.GetDirectories : GetDirSize(SubFolderInfo.FullName)
        Next
        Return TotalSize
    End Function

    Public Sub GetfilesizeFromDirectory()
        Dim path As String
        path = "D:"
        TotalSize = 0 'Reset the counter
        Dim TheSize As Long = GetDirSize(path)
        ' TextBox1.Text = (FormatNumber(TheSize / 1024 / 1024 / 1) & vbCr & "MB")
    End Sub
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