How do you convert hex to decimal using VB.NET?

Question

Need to convert Hex to a Decimal in VB.Net. Found several examples in C#, but when I tried to convert to VB.Net I was not successful. Here is an example of a hexidecimal number that I am trying to convert "A14152464C203230304232323020572F544947455234352E".

Thanks,

Dave

Answer 1

Write one yourself.

You will need to tokenize the string, then start from the right, and work your way left.

int weight = 1;
While Looping
{

  If (token(i) == "F") { DecimalValue += 15 * weight; }
  If (token(i) == "E") { DecimalValue += 14 * weight; }
  If (token(i) == "D") { DecimalValue += 13 * weight; }
  If (token(i) == "C") { DecimalValue += 12 * weight; }
  If (token(i) == "B") { DecimalValue += 11 * weight; }
  If (token(i) == "A") { DecimalValue += 10 * weight; }
  else { DecimalValue += token(i) * weight; }

  weight = weight * 10;
}

Something like that.

Answer 2

 Dim hex As String
 hex = "A14152464C203230304232323020572F544947455234352E"

 Dim dec As Long
 Dim hexpart As String
 For x As Integer = 1 To (hex.Length / 2)

  hexpart = hex.Substring((x * 2) - 2, 2)
  dec = Int32.Parse(hexpart, System.Globalization.NumberStyles.HexNumber)

  Debug.Print("Hex = " + hex + ",HexPart = " + hexpart + ", Dec = " + dec.ToString + Environment.NewLine)
 Next

This won't work for Decimal and the Hex is too long for integer... but you get the idea. You could split it and recombine.

Hex = A14152464C203230304232323020572F544947455234352E,HexPart = A1, Dec = 161

Hex = A14152464C203230304232323020572F544947455234352E,HexPart = 41, Dec = 65

Hex = A14152464C203230304232323020572F544947455234352E,HexPart = 52, Dec = 82

Hex = A14152464C203230304232323020572F544947455234352E,HexPart = 46, Dec = 70

Hex = A14152464C203230304232323020572F544947455234352E,HexPart = 4C, Dec = 76

Hex = A14152464C203230304232323020572F544947455234352E,HexPart = 20, Dec = 32

Hex = A14152464C203230304232323020572F544947455234352E,HexPart = 32, Dec = 50

Hex = A14152464C203230304232323020572F544947455234352E,HexPart = 30, Dec = 48

Hex = A14152464C203230304232323020572F544947455234352E,HexPart = 30, Dec = 48

Hex = A14152464C203230304232323020572F544947455234352E,HexPart = 42, Dec = 66

Hex = A14152464C203230304232323020572F544947455234352E,HexPart = 32, Dec = 50

Hex = A14152464C203230304232323020572F544947455234352E,HexPart = 32, Dec = 50

Hex = A14152464C203230304232323020572F544947455234352E,HexPart = 30, Dec = 48

Hex = A14152464C203230304232323020572F544947455234352E,HexPart = 20, Dec = 32

Hex = A14152464C203230304232323020572F544947455234352E,HexPart = 57, Dec = 87

Hex = A14152464C203230304232323020572F544947455234352E,HexPart = 2F, Dec = 47

Hex = A14152464C203230304232323020572F544947455234352E,HexPart = 54, Dec = 84

Hex = A14152464C203230304232323020572F544947455234352E,HexPart = 49, Dec = 73

Hex = A14152464C203230304232323020572F544947455234352E,HexPart = 47, Dec = 71

Answer 3

That is a 24-byte (192-bit) number; what value are you expecting?

Note that you can use Convert to do a lot of the grungy work here - for example (in C#):

    string hex = "A14152464C203230304232323020572F544947455234352E";
    byte[] raw = new byte[hex.Length / 2];
    for (int i = 0; i < raw.Length ; i++)
    {
        raw[i] = Convert.ToByte(hex.Substring(i * 2,2), 16);
    }

How you get from raw to a number depends on what you think the number is...

VB translation courtesy of reflector (although the "-1" looks odd):

Dim hex As String = "A14152464C203230304232323020572F544947455234352E"
Dim raw As Byte() = New Byte((hex.Length / 2)  - 1) {}
Dim i As Integer
For i = 0 To raw.Length - 1
    raw(i) = Convert.ToByte(hex.Substring((i * 2), 2), &H10)
Next i

Answer 4

This will convert your string into an array of bytes:

Dim hex As String = "A14152464C203230304232323020572F544947455234352E"

Dim len As Integer = hex.Length \ 2
Dim data(len - 1) As Byte
For i As Integer = 0 to len - 1
   data(i) = Convert.ToByte(hex.Substring(i * 2, 2), 16)
Next

Answer 5

Private Function toByte(ByVal Shex As String) As List(Of Byte)
    Const cvtCH As Integer = 2
    Dim retval As New List(Of Byte)
    Dim rmndr As Integer
    rmndr = Shex.Length Mod cvtCH
    If rmndr <> 0 Then Shex = Shex.PadLeft(Shex.Length + cvtCH - rmndr, "0"c)
    For x As Integer = 0 To Shex.Length - 1 Step cvtCH
        retval.Add(Convert.ToByte(Shex.Substring(x, cvtCH), 16))
    Next
    Return retval
End Function
Private Function toU32(ByVal Shex As String) As List(Of UInt32)
    Const cvtCH As Integer = 8
    Dim retval As New List(Of UInt32)
    Dim rmndr As Integer
    rmndr = Shex.Length Mod cvtCH
    If rmndr <> 0 Then Shex = Shex.PadLeft(Shex.Length + cvtCH - rmndr, "0"c)
    For x As Integer = 0 To Shex.Length - 1 Step cvtCH
        retval.Add(Convert.ToUInt32(Shex.Substring(x, cvtCH), 16))
    Next
    Return retval
End Function
Private Function toU64(ByVal Shex As String) As List(Of UInt64)
    Const cvtCH As Integer = 16
    Dim retval As New List(Of UInt64)
    Dim rmndr As Integer
    rmndr = Shex.Length Mod cvtCH
    If rmndr <> 0 Then Shex = Shex.PadLeft(Shex.Length + cvtCH - rmndr, "0"c)
    For x As Integer = 0 To Shex.Length - 1 Step cvtCH
        retval.Add(Convert.ToUInt64(Shex.Substring(x, cvtCH), 16))
    Next
    Return retval
End Function
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    'unsigned 32 bit max = FFFFFFFF
    'unsigned 64 bit max = FFFFFFFF
    'signed 32 bit max = 7FFFFFFF
    'signed 64 bit max = 7FFFFFFF
    Dim hexS As String = "A14152464C203230304232323020572F544947455234352E"
    Dim hexS2 As String = "A14152464C203230304232323020572F54494745523435"
    toByte(hexS)
    toU32(hexS)
    toU64(hexS)
End Sub

Answer 6

For hex values which don't actually require a bignum class to work with, you can use the normal conversion function but prefix the number with "&H". VB interprets "&H" in the text as meaning "this is a hex number", just like it does in code.

dim n = Cint("&H" & text)