Private Function CompareFiles(ByVal filePathOne As String, ByVal filePathTwo As String) As Boolean

 

    Dim fileOneByte As Integer

    Dim fileTwoByte As Integer

 

    Dim fileOneStream As FileStream

    Dim fileTwoStream As FileStream

 

    ' If user has selected the same file as file one and file two....

    If (filePathOne = filePathTwo) Then

        ' Files are the same.

        Me.ResultsRichTextBox.Text = "Files are the same; file one is file two."

        Return True

    End If

 

    ' Open a FileStream for each file.

    fileOneStream = New FileStream(filePathOne, FileMode.Open)

    fileTwoStream = New FileStream(filePathTwo, FileMode.Open)

 

    ' If the files are not the same length...

    If (fileOneStream.Length <> fileTwoStream.Length) Then

        fileOneStream.Close()

        fileTwoStream.Close()

        ' File's are not equal.

        Me.ResultsRichTextBox.Text = "Files are not the same length; they are not equal."

        Return False

    End If

 

    Dim areFilesEqual As Boolean = True

 

    ' Loop through bytes in the files until

    '  a byte in file one <> a byte in file two

    ' OR

    '  end of the file one is reached.

    Do

        ' Read one byte from each file.

        fileOneByte = fileOneStream.ReadByte()

        fileTwoByte = fileTwoStream.ReadByte()

        If fileOneByte <> fileTwoByte Then

            ' Files are not equal; byte in file one <> byte in file two.

            Me.ResultsRichTextBox.Text = "Files are not equal; contents are different."

            areFilesEqual = False

            Exit Do

        End If

    Loop While (fileOneByte <> -1)

 

    ' Close the FileStreams.

    fileOneStream.Close()

    fileTwoStream.Close()

 

    Return areFilesEqual

 

 End Function