Converting from octal to binary in vb.net

Question

I want to convert an octal number to binary for purposes related to my avionics (transponders to be specific). I do vb.net in my spare time, learning on my own. But for this, I'm not sure how to do it, even after googling.

Here is how I have it set up so far: form1

Here's all the code I have so far. This is so only numers 1-7 can be entered:

Public Class Form1    
Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As
System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
    If Asc(e.KeyChar) <> 8 Then
        If Asc(e.KeyChar) < 48 Or Asc(e.KeyChar) > 55 Then
            e.Handled = True
        End If
    End If
End Sub
End Class

I'm not sure how to convert Textbox1.text into binary and then separate it into the following textboxes for A,B,C,D.

Ex: You have A4, A2, and A1 (the 000). Those add to 7 (111). This is repeated for B,C, and D.

So to sum things up, I want to convert the octal number into binary and, if I can, separate it into separate boxes corresponding to the letters.

This is how it should look (can't post more than 2 links): 2134 = A4,2,1(010) B4,2,1(001) C4,2,1(011) D4,2,1(100)

Edit: I have tried Convert.ToString(#NUMBER, 2) but it returns the wrong binary code. 7631 returns 1110111001111 but it should be 111110011001. See http: //ncalculators.com/digital-computation/binary-octal-converter.htm

Answer 1

To convert an octal string to a binary string:

Private Function OctToBin(octal As String) As String
    Return Convert.ToString(Convert.ToInt32(octal, 8), 2)
End Function

To convert a binary string into an array of three-character substrings:

Private Function ToBinBytes(binary As String) As String()
    Dim chars = binary.Reverse().ToArray()
    Dim binBytes As New List(Of String)

    Do While chars.Length > 0
        Dim byteChars = chars.Take(3).Reverse().ToArray()

        binBytes.Add(New String(byteChars).PadLeft(3, "0"c))
        chars = chars.Skip(3).ToArray()
    Loop

    Return binBytes.AsEnumerable().Reverse().ToArray()
End Function

Both are untested but I think they're right.

Tested with this code:

Dim n = 1234567
Dim o = Convert.ToString(n, 8)
Dim b = OctToBin(o)

MessageBox.Show((n = Convert.ToInt32(b, 2)).ToString())
MessageBox.Show(String.Join(Environment.NewLine, ToBinBytes(b)), b)