vb.net怎么获取mp3文件的大小？

首先引入System.IO命名空间（在代码文件的最上方）

Imports System.IO

然后在需要用到的地方：

Dim mp3fileinfo As New FileInfo(mp3文件完整路径字符串)

'mp3fileinfo.Length就是文件的大小，以B（字节）为单位，除以1024得到KB，再除以1024得到MB

窗体上添加一个按钮，代码如下：

Public Class Form1

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

Button1.Text = "稍等！"

Button1.Enabled = False

Dim MyFolder As String = "C:\Windows"

Dim MyDir As New System.IO.DirectoryInfo(MyFolder)

Dim MyInfo As String = MyFolder + "文件夹的大小是：" + CalculateDirectorySize(MyDir, True).ToString() + "字节。"

MessageBox.Show(MyInfo, "信息提示", _

MessageBoxButtons.OK, MessageBoxIcon.Information)

Button1.Text = "开始"

Button1.Enabled = True

End Sub

Public Shared Function CalculateDirectorySize(ByVal MyDirectory As System.IO.DirectoryInfo, ByVal IsSubDirectories As Boolean) As Long

Dim MySize As Long = 0

'检查包含的所有文件

Dim MyFiles() As System.IO.FileInfo = MyDirectory.GetFiles()

For Each MyFile As System.IO.FileInfo In MyFiles

MySize += MyFile.Length

Next

'检查包含的所有子文件夹

If (IsSubDirectories) Then

Dim MyDirs() As System.IO.DirectoryInfo = MyDirectory.GetDirectories()

For Each MyDir As System.IO.DirectoryInfo In MyDirs

MySize += CalculateDirectorySize(MyDir, True)

Next

End If

Return MySize

End Function

End Class

CSV文件特征是每行一条记录，字段用逗号分开。你只需要逐行处理，将每行文本用逗号切分得到数组array，然后判断array[0]是否等于"bbb"，如果相等则array[1]就是”4561234567890“；如果不等则继续处理下一行。

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