Convert textbox input to hexadecimal number

Question

I try to find answer  for my question in the previous thread but i can't found it. 

my problem is:

i want to convert a string entered by a user from textbox to hexadecimal number. 

the string is the hexadecimal code ( 0 - F ) 

for example if the user entered "12345678"

the string entered will be represented in an array like this:

array(0) = &H12

array(1) = &H34

array(2) = &H56

array(3) = &H78

and also if the input is like this : "1234"

the arrangement of the array is:

array(0) = &H01

array(1) = &H02

array(2) = &H03

array(3) = &H04

 

hopefully my question is clear. 

thank you. 

 

Answer 1

Hello Red,

I've just programmed a Hex Editor. Here is my code. Part1: Enter string n Hexformat only 0 ..9, A..F into a Box

Part2: convert this string to byte array. This also works with a TextBox

sucess and best regards Ellen

 Private count As Integer
 '
 ' enter text in Format 1F AA 01 A1 e3 ..........
 '
 Private Sub ComboBox1_TextUpdate(ByVal sender As System.Object, _
          ByVal e As System.EventArgs) _
          Handles cbxEnterText.TextUpdate

  If Not txEnterHex.Checked Then Exit Sub
  Dim cb As ToolStripComboBox = CType(sender, ToolStripComboBox)
  count += 1
  If count = 2 Then
   cb.Text &= " "
   count = 0
  End If
 
 End Sub
 '
 ' only allowed hex keys 
 '
 Private Sub ComboBox1_KeyPress(ByVal sender As System.Object, _
         ByVal e As System.Windows.Forms.KeyPressEventArgs) _
         Handles cbxEnterText.KeyPress

  Dim allowedChars As String = "0123456789ABCDEFabcdef"
  Dim found As Boolean

  If e.KeyChar <> keys.Enter Then
   If txEnterHex.Checked Then
    For i As Integer = 1 To allowedChars.Length
     If e.KeyChar = GetChar(allowedChars, i) Then
      found = True
      Exit For
     End If
    Next

    If Not found Then
     e.Handled = True
    End If
   End If
  Else
   count = 0
   '
   ' here code to convert the line to hex array
   ' 
    reconvert(cbxEnterText.Text)
  End If

 End Sub



 '
 ' convert string 1F AA 01 A1 e3 .......... to binary array
 '
 Private Function reconvert(ByVal t As String) As Byte()
  Dim data() As Byte = Nothing
  Dim s() As String = t.Split(New String() {" "}, StringSplitOptions.RemoveEmptyEntries)
  data = New Byte(s.Length - 1) {}
  For i As Integer = 0 To data.Length - 1
   If Not Byte.TryParse(s(i), NumberStyles.HexNumber, CultureInfo.CurrentCulture, data(i)) Then
    data(i) = 255
    MsgBox("error converting!", MsgBoxStyle.Information)
   End If
  Next
  Return data
 End Function

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Ich benutze/ I'm using VB2008 & VB2010

Answer 2

Hi Red,

You can do things difficult and do things normal. 

Hex is not a kind of value or whatever, it is a representation of a value.

10 is represented in Hex notation A while it is in octal 12

Internal it is just the same it are the bits

1010

Be aware that this is not equivalent to a code system where in Net is currently mostly used for numbers a code which is for all code tables the same.

The written number 1 is in that equal to code 49 which is in hexadecimal notation 31 which has to do with the bits because it is just meaning

0010001

For conversion in this are in VB the conversion methods 

for instance Hex, ASC, ASCW, Chrw, Chr

http://msdn.microsoft.com/en-us/library/1bbh5ae4(v=VS.100).aspx

---

Success
Cor

Answer 3

thank you for the quick reply and the answer is really2 helpful.. 

Answer 4

hi ellen, i got problem with your code. sorry because i'm really at the beginner stage of exploring vb.net. 

fisrtly i do not understand your withevent code of 

Private Sub ComboBox1_TextUpdate(ByVal sender As System.Object, _

     ByVal e As System.EventArgs) _
     Handles cbxEnterText.TextUpdate

where does the cbxentertext come from?

Answer 5

hi ellen, i got problem with your code. sorry because i'm really at the beginner stage of exploring vb.net. 

fisrtly i do not understand your withevent code of 

Private Sub ComboBox1_TextUpdate(ByVal sender As System.Object, _

   ByVal e As System.EventArgs) _

   Handles cbxEnterText.TextUpdate

where does the cbxentertext come from?

Hello red,

sorry for my delayed reply. What You see here is special feature (or bug ... ) in Visual Studio. When I design a Combobox with Form Designer the default name is ComboBox1. I usually then rename the identifieres here to cbxententerText. But this will not automatically change the name of the event routine. here remains the name ComboBox1_TextDown. But this is no issue. Try to rename this to any name. You will see the code runs. The reason is: The Sub will be executed by the Handle and not by the method name.

best regards Ellen

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Ich benutze/ I'm using VB2008 & VB2010