Dealing with null character in VB.NET - vb.net

Question

I am trying to open a binary file in VB.NET (Visual Studio 2010), that looks like this:
The file opens ok with this method:
Dim OpenFile1 As New OpenFileDialog
If (OpenFile1.ShowDialog = System.Windows.Forms.DialogResult.OK And (OpenFile1.FileName.Length > 0)) Then
'do something
End If
However, if "do something" is:
Dim readText As String = File.ReadAllText(OpenFile1.FileName)
MsgBox(readText)
Only the first byte is converted, as the second one is 00 (null) and truncates the rest of the file, marking the end of the string, and it displays only the first byte F0 (≡ in ASCII).
But if I do:
'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
Now the string is properly converted to hex values. So far so good.
However, when I try to convert the string back to ASCII using this method:
'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
Again, only the first byte is converted. The rest is truncated as soon as it finds a 00 (null).
Is there a way to circumvent this situation?

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.