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I have this conversion in my Kotlin class for Android:

val binary = "01000100000111001011011011100010111000110011010111010110"
val hexadecimal = BigInteger(binary, 2).toString(16)

Which is producing the expected value of 441CB6E2E335D6.

Now I want to reproduce this in Visual Basic and I am doing something like this:

Dim binary = "01000100000111001011011011100010111000110011010111010110"
Dim hexadecimal = BigInteger.Parse(binary, 2).ToString("X")

Which is producing 0A7108304A751AFEC876F740BC1F2CB59772FB7C6C753E.

I am not an expert in Visual Basic, but from what I researched, I think this is the right way to convert a binary to hexadecimal. What I am doing wrong?

You can write a simple parser for the string representing the bits:

Dim sb As StringBuilder = New StringBuilder()
For pos As Integer = 0 To binary.Length - 8 Step 8
 sb.Append(Convert.ToByte(binary.Substring(pos, 8), 2).ToString("X2"))
Next

Console.WriteLine(sb) will print "441CB6E2E335D6"

Or use a Module to add an extension method to the string data type:

Imports System.Runtime.CompilerServices
Imports System.Text

Module modStringExtensions
 <Extension()>
 Public Function ToHexFromBits(ByVal Value As String) As String
 If (Not (Value.Length Mod 8 = 0)) Then Throw New FormatException("Invalid string length")
 Dim sb As StringBuilder = New StringBuilder()
 For pos As Integer = 0 To Value.Length - 8 Step 8
 sb.Append(Convert.ToByte(Value.Substring(pos, 8), 2).ToString("X2"))
 Next
 Return sb.ToString()
 End Function
End Module

Then use the extension to convert the bits string to a HEX representation:

Dim result As String = binary.ToHexFromBits()

Following code is c#, but might not be too hard to translate it to vb.net.

string BinToHex(string value)

 var res = new char[(int)(value.Length / 4)];
 int j = res.Length-1;
 for (int i = value.Length - 1; i > 0; i -= 4)
 
 int x = ((int)value[i]-48) 
 +((int)value[i-1]-48)*2
 +((int)value[i-2]-48)*4
 +((int)value[i-3]-48)*8;

 res[j--] = x.ToString("X")[0];
 

 return new string(res);

Beware: it won't handle input that has not the proper number of bits (multiple of 4). Anyway, the idea is that you can translate between base 2 and base 16 without the use of base 10. You could even step from left to right.