Question

我试图在VB.NET 2010中创建一个具有简单功能的程序。它必须将存储在文本文件中的数千个MD5哈希值与当前文件MD5哈希值进行比较，该程序在打开文件时自动计算。像一个防病毒扫描程序。实际上我的程序使用ReadAllText系统将文本文件中的所有哈希值添加到文本框中，然后进行比较。

当Md5数据库（带有哈希的文本文件）很小但是当文件变大时，我的程序只是在打开后冻结，所以我决定使用ReadLine而不是ReadAllText。< / p>

现在我不能再使用文本框，所以请告诉我如何比较它们。我尝试了一种方法，但它似乎不起作用。

以下是使用ReadLine的代码。

问题出现在If Read contains(buff.tostring)上如果textbox.text包含（buff.toString）

这是代码

Try
            TextBox2.Text = e.FullPath
            ListBox3.Items.Add(TextBox2.Text.ToString)
            Me.OpenFileDialog1.FileName = ""
            Dim reader As StreamReader = New StreamReader("def.txt")
            Dim read = reader.ReadLine()
            Dim md5 As New MD5CryptoServiceProvider
            Dim f As New FileStream(e.FullPath, FileMode.Open, FileAccess.Read, FileShare.Read, &H2000)
            f = New FileStream(e.FullPath, FileMode.Open, FileAccess.Read, FileShare.Read, &H2000)
            md5.ComputeHash(f)
            Dim hash As Byte() = md5.Hash
            Dim buff As New StringBuilder
            Dim hashByte As Byte
            For Each hashByte In hash
                buff.Append(String.Format("{0:X2}", hashByte))
            Next
            f.Close()
            If read.Contains(buff.ToString) Then
                Me.OpenFileDialog1.FileName = e.FullPath
                Form2.ShowDialog()

            End If

        Catch exception1 As Exception
            ProjectData.SetProjectError(exception1)
            Dim ex As Exception = exception1
            ProjectData.ClearProjectError()
        End Try

Answer 1

我首先会创建功能来分割功能。之后理解代码要容易得多。将哈希存储在列表中，然后可以缓存此列表。

Try

    TextBox2.Text = e.FullPath
    ListBox3.Items.Add(TextBox2.Text.ToString)
    Me.OpenFileDialog1.FileName = ""

    Dim allHash As List(Of String) = GetAllHash()
    Dim curHash As String = GetFileHash(e.FullPath)

    If allHash.Contains(curHash) Then
        Me.OpenFileDialog1.FileName = e.FullPath
        Form2.ShowDialog()
    End If

Catch exception1 As Exception
    ProjectData.SetProjectError(exception1)
    Dim ex As Exception = exception1
    ProjectData.ClearProjectError()
End Try

Function GetAllHash() As List(Of String)

    ' Store the data in a list instead
    Return System.IO.File.ReadAllLines("def.txt").ToList()
End Function

Function GetFileHash(ByVal filename As String) As String

    Dim md5 As New MD5CryptoServiceProvider
    ' Only open the file once
    Dim f As New FileStream(filename, FileMode.Open, FileAccess.Read, FileShare.Read, &H2000)
    md5.ComputeHash(f)
    Dim hash As Byte() = md5.Hash
    Dim buff As New StringBuilder

    For Each hashByte As Byte In hash
        buff.Append(String.Format("{0:X2}", hashByte))
    Next

    f.Close()

    Return buff.ToString()
End Function

我没有编译这段代码，这只是一个向你展示可以做些什么的例子。

VB.NET MD5使用大文件进行比较

1 个答案: