在VB.NET中处理空字符

Question

我试图在VB.NET（Visual Studio 2010）中打开一个二进制文件，如下所示：

使用以下方法可以正常打开文件：

Dim OpenFile1 As New OpenFileDialog
If (OpenFile1.ShowDialog = System.Windows.Forms.DialogResult.OK And (OpenFile1.FileName.Length > 0)) Then
      'do something
End If

但是，如果“做某事”是：

Dim readText As String = File.ReadAllText(OpenFile1.FileName)
MsgBox(readText)

仅第一个字节被转换，第二个字节为00（空），并截断文件的其余部分，标记字符串的结尾，并且仅显示第一个字节F0（ASCII中的≡）。

但如果我这样做：

'convert file to hex string
Dim bytes As Byte() = IO.File.ReadAllBytes(OpenFile1.FileName)
Dim hex As String() = Array.ConvertAll(bytes, Function(b) 
b.ToString("X2"))
Dim newfile As String
newfile = (String.Join("", hex))
RichTextBox1.Text = newfile

现在，字符串已正确转换为十六进制值。到目前为止一切顺利。

但是，当我尝试使用此方法将字符串转换回ASCII时：

 'convert hex string to text and put it into the richtextbox
 Dim asciistring As String = ""
 For x As Integer = 0 To (newfile.Length - 1) Step 2
      Dim k As String = newfile.Substring(x, 2)
      asciistring &= System.Convert.ToChar(System.Convert.ToUInt32(k, 
 16)).ToString()
 Next
 RichTextBox1.Text = asciistring

同样，仅转换第一个字节。其余的一旦找到00（空），就会被截断。 有办法避免这种情况吗？

Answer 1

Haven't tested out this code yet, but you can try give this method a try :

Public Shared Function ConvertHex(ByVal hexString As String) As String
Try
    Dim ascii As String = String.Empty

    For i As Integer = 0 To hexString.Length - 1 Step 2
        Dim hs As String = String.Empty
        hs = hexString.Substring(i, 2)
        Dim decval As UInteger = System.Convert.ToUInt32(hs, 16)
        Dim character As Char = System.Convert.ToChar(decval)
        ascii += character
    Next

    Return ascii
Catch ex As Exception
    Console.WriteLine(ex.Message)
End Try

Return String.Empty
End Function

When calling the function, just pass your hex string.