如何比较 vb.net 中的字节数组

Question

好的，我想做的只是比较 vb.net 中的 2 个字节数组。我尝试了这些代码：

If Byte.ReferenceEquals(bytearrayone, bytearraytwo) Then
  MsgBox("Yes", MsgBoxStyle.Information)
Else
  MsgBox("No", MsgBoxStyle.Critical)
End If

和

If Array.ReferenceEquals(bytearrayone, bytearraytwo) Then
  MsgBox("Yes", MsgBoxStyle.Information)
Else
  MsgBox("No", MsgBoxStyle.Critical)
End If

两个字节数组

是相同的，一个数组从资源中获取文件字节，另一个从计算机中获取字节。出于测试目的，我在两个数组中都使用了相同的文件，但根据提供的代码，我得到的只是 No。两者都具有相同的长度，我遍历了它们，它们在相同的点上都有相同的字节。那怎么了？我应该使用什么代码？请帮助我。

Answer 1

使用 SequenceEqual

    Dim foo() As Byte = {1, 2, 3, 4}
    Dim barT() As Byte = {1, 2, 3, 4}
    Dim barF() As Byte = {1, 2, 3, 5}
    Dim fooEqbarT As Boolean = foo.SequenceEqual(barT)
    Dim fooEqbarF As Boolean = foo.SequenceEqual(barF)
    Debug.WriteLine(fooEqbarT)
    Debug.WriteLine(fooEqbarF)

比较两个小文件

    Dim path1 As String = "pathnameoffirstfile"
    Dim path2 As String = "pathnameofsecondfile"
    Dim foo() As Byte = IO.File.ReadAllBytes(path1)
    Dim bar() As Byte = IO.File.ReadAllBytes(path2)
    If foo.SequenceEqual(bar) Then
        'identical
    Else
        'different
    End If

Answer 2

如果您的目的是比较 2 个文件以查看内容是否相同，而不考虑有关文件的信息（即修改日期、名称、类型等），您应该对两个文件使用哈希。这是我使用一段时间的一些代码。有很多方法可以做到这一点。

''' <summary>
''' Method to get a unique string to idenify the contents of a file.
''' Works on any type of file but may be slow on files 1 GB or more and large files across the network.
''' </summary>
''' <param name="FI">System.IO.FileInfo for the file you want to process</param>
''' <returns>String around 50 characters long (exact length varies)</returns>
''' <remarks>A change in even 1 byte of the file will cause the string to vary 
''' drastically so you cannot use this to see how much it differs by.</remarks>
Public Shared Function GetContentHash(ByVal FI As System.IO.FileInfo) As String
    Dim SHA As New System.Security.Cryptography.SHA512Managed()
    Dim sBuilder As System.Text.StringBuilder
    Dim data As Byte()
    Dim i As Integer
    Using fs As New IO.FileStream(FI.FullName, IO.FileMode.Open)
        data = SHA.ComputeHash(fs)
        fs.Flush()
        fs.Close()
    End Using
    sBuilder = New System.Text.StringBuilder
    ' Loop through each byte of the hashed data 
    ' and format each one as a hexadecimal string.
    For i = 0 To data.Length - 1
        sBuilder.Append(data(i).ToString("x2"))
    Next i
    Return sBuilder.ToString()
End Function

您需要在每个文件上运行它，以提出唯一标识文件的字符串，然后比较 2 个字符串。