Cacher is the code snippet organizer for pro developers

//比较2个文件是否一致
Private Function CompareFiles(ByVal file1 As String, ByVal file2 As String) As Boolean
    ' Set to true if the files are equal; false otherwise
    Dim filesAreEqual As Boolean = False

    With My.Computer.FileSystem
        ' Ensure that the files are the same length before comparing them line by line.
        If .GetFileInfo(file1).Length = .GetFileInfo(file2).Length Then
            Using file1Reader As New FileStream(file1, FileMode.Open), _
                  file2Reader As New FileStream(file2, FileMode.Open)
                Dim byte1 As Integer = file1Reader.ReadByte()
                Dim byte2 As Integer = file2Reader.ReadByte()
                ' If byte1 or byte2 is a negative value, we have reached the end of the file.
                While byte1 >= 0 AndAlso byte2 >= 0
                    If (byte1 <> byte2) Then
                        filesAreEqual = False
                        Exit While
                    Else
                        filesAreEqual = True
                    End If
                    ' Read the next byte.
                    byte1 = file1Reader.ReadByte()
                    byte2 = file2Reader.ReadByte()
                End While
            End Using
        End If
    End With

    Return filesAreEqual
End Function

//读取大文本
Public Function ReadFile(ByVal FilePath As String) As String
    Dim Value As String = Nothing
    Dim fs As FileStream = File.OpenRead(FilePath)
    Dim lineString As String

    Using sr As New StreamReader(fs, System.Text.Encoding.Default)
        'While Not sr.EndOfStream '循环直到流结束
        Static i As Integer '读取行数
        Do
            lineString = sr.ReadLine() '读一行
            If lineString.StartsWith("itm_newa,geo\time") Then
                Value += (lineString & vbCrLf)
                'Console.WriteLine("Drive:" & lineString.Split("\")(0).ToString())
                i += 1
                If i >= 20 Then
                    Exit Do
                End If
            End If
            Value += (lineString & vbCrLf)
        Loop Until (sr.EndOfStream)
        sr.Close()
    End Using
    '大文本分字节大小读取
    'Using fs As FileStream = File.OpenRead(FilePath)
    '    Dim b As Byte() = New Byte(1023) {}
    '    Dim temp As New UTF8Encoding(True)
    '    While fs.Read(b, 0, b.Length) > 0
    '        Value += temp.GetString(b)
    '    End While
    'End Using
    Return Value
End Function

//递归搜索文件(高效)
Imports System.IO
Public Class Form1
    '窗体控件分别是 FolderBrowserDialog1,Button1,Label1,Listbox1
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        ListBox1.Items.Clear()

        Me.FolderBrowserDialog1.ShowDialog()
        Dim Myarr As New ArrayList
        Sel(Directory.GetFiles(FolderBrowserDialog1.SelectedPath, "*", SearchOption.AllDirectories), "*.txt", Myarr)

        Dim Mystr As String
        For Each Mystr In Myarr
            ListBox1.Items.Add(Mystr)
            Debug.Print(Mystr) '请查看下方即时窗口消息
        Next


        'Label1.Text = FolderBrowserDialog1.SelectedPath.ToString & "路径下共有文件" _
        '& ListBox1.Items.Count.ToString & "个"
    End Sub

    Private Sub Sel(ByVal Filenames() As String, ByVal FileClass As String, ByRef Myarr As ArrayList) '传入值Filenames() [文件组()地址],FileClass文件类形,地址变量数组列表用来传出文件名
        Try
  
            Dim i As Integer
            For Each Filenames(i) In Filenames
                'Application.DoEvents()
                If Filenames(i) Like FileClass Then '文件名匹配筛选

                    Myarr.Add(Filenames(i))
                    Dim fi As New System.IO.FileInfo(Filenames(i))

                    '文件大小控制
                    'If fi.Length > 1000000000 Then
                    '    MsgBox(filenames(i) & "大于1G")
                    'End If
                End If

            Next

        Catch ex As Exception
            ex.Message.ToString()
        End Try
    End Sub

End Class