Problems with hex values stored in a textbox to integers

[jbrookley]

Hello everyone!

I am reading back information on my serial port into a textbox and trying to convert it into an integer but hit some issues. The value comes in as a 6 separate characters, starting with "2A" if it's a good value, and then followed by 4 hex values. I basically am storing this into a character array, checking the first two letters to make sure they read "2A", then trying to convert the last 4 hex values into an integer.

The issue I'm having is with the conversion from the char array to integer. Below is my current code:

        Autozero As Integer = 0

        Dim temparray2() As Char = TextBox3.Text         'The hex values are stored in this textbox in string form

        If temparray2(0) = "2" And temparray2(1) = "A" Then
                Autozero = Convert.ToInt16("&H" & temparray2(2) & temparray2(3) & temparray2(4) & temparray2(5))     
        End If

The problem is the value is basically stored as:

"&H1FCC"

rather than

&H1FCC

If I do:

Autozero = Convert.ToString(&H1FCC)

it works correctly. However, if I do:

Autozero = Convert.ToString("&H1FCC")

which is essential what my program is doing above, I have a problem and it breaks here.

I might actually have the wrong approach and maybe there's a better way to do this. If you have any suggestions, please let me know. Thanks!

[JuggaloBrotha]

Dim ba As Byte() = Encoding.[Default].GetBytes("sample")
Dim hexString As String= BitConverter.ToString(ba).Replace("-", String.Empty)

As gotten from here:
http://stackoverflow.com/questions/1...ing-in-c-sharp

[jmcilhinney]

You should NEVER use "&H" in text when working with hexadecimal numbers. That is specifically a prefix for hexadecimal literals in VB code. That's the only place it should be used. To convert a number to a hexadecimal string, I would recommend calling that number's ToString method. To convert from a hexadecimal string to an Integer, use Convert.ToInt32 or Integer.TryParse, e.g.

Dim n1 = 1000
Dim n2 = &HA3F

MessageBox.Show(n1.ToString("X"))
MessageBox.Show(n2.ToString("x"))

Dim h1 = "a1b2c3"
Dim h2 = "DEF"
Dim h3 = "fgh"

Dim n3 = Convert.ToInt32(h1, 16)

MessageBox.Show(n3.ToString())

Dim n4 As Integer

If Integer.TryParse(h2, NumberStyles.AllowHexSpecifier, Nothing, n4) Then
    MessageBox.Show(n4.ToString())
Else
    MessageBox.Show("Not a number")
End If

Dim n5 As Integer

If Integer.TryParse(h3, NumberStyles.AllowHexSpecifier, Nothing, n5) Then
    MessageBox.Show(n5.ToString())
Else
    MessageBox.Show("Not a number")
End If