5 replies to this topic

[Charles]

I wrote the following code: Byte test = new Byte(); test = 190; Debug.Print(test.ToString("X2")); And I get this: #### Exception System.ArgumentException - 0x00000000 (3) #### Anyone know why??

[Chris Walker]

.NET Micro Framework doesn't support hex conversion/formatting using .ToString("X2"). This is one of the areas where Microsoft needed to reduce the footprint of the runtime. There are a number of hex conversion routines for .NET MF on the web. I know that we've built one too. If you have trouble finding one, please post here and I'll see if I can track one down for you... Chris

[Charles]

Thanks for clearing that up! Thought I was losing my mind...

[Charles]

For anyone who needs this, here's a handy code snipplet to make the N+ cough up its MAC address.

It is loosely based on some examples off the Internet for converting hex codes, but has been modified significantly to improve readability/strip out unnecessary code.

// Access variable to the network subsystem.
NetworkInterface[] netIF = NetworkInterface.GetAllNetworkInterfaces();

string macAddress = "";

// Create a character array for hexidecimal conversion.
const string hexChars = "0123456789ABCDEF";

// Loop through the bytes.
for (int b = 0; b < 6; b++)
{
    // Grab the top 4 bits and append the hex equivalent to the return string.
    macAddress += hexChars[netIF[0].PhysicalAddress[b] >> 4];

    // Mask off the upper 4 bits to get the rest of it.
    macAddress += hexChars[netIF[0].PhysicalAddress[b] & 0x0F];
                    
    // Add the dash only if the MAC address is not finished.
    if (b < 5) macAddress += "-";
}

return macAddress;

[ColinR]

Thanks Charles, great code!

I know it's petty changes, but I changed the NetworkInterface variable to only store the single item, and I changed the int to a byte - saving a smidgen of RAM!

// Access variable to the network subsystem.
NetworkInterface ni = NetworkInterface.GetAllNetworkInterfaces()[0];

string macAddress = "";

// Create a character array for hexidecimal conversion.
const string hexChars = "0123456789ABCDEF";

// Loop through the bytes.
for (byte b = 0; b < 6; b++)
{
	// Grab the top 4 bits and append the hex equivalent to the return string.
	macAddress += hexChars[ni.PhysicalAddress[b] >> 4];

	// Mask off the upper 4 bits to get the rest of it.
	macAddress += hexChars[ni.PhysicalAddress[b] & 0x0F];

	// Add the dash only if the MAC address is not finished.
	if (b < 5) macAddress += "-";
}

return macAddress;

[jimox]

If it is helpful I have been using this:

public static class BitConverter
{
    public static string ToString(byte[] value, int index = 0)
    {
        return ToString(value, index, value.Length - index);
    }

    public static string ToString(byte[] value, int index, int length)
    {
        char[] c = new char[length * 3];
        byte b;

        for (int y = 0, x = 0; y < length; ++y, ++x)
        {
            b = (byte)(value[index + y] >> 4);
            c[x] = (char)(b > 9 ? b + 0x37 : b + 0x30);
            b = (byte)(value[index + y] & 0xF);
            c[++x] = (char)(b > 9 ? b + 0x37 : b + 0x30);
            c[++x] = '-';
        }
        return new string(c, 0, c.Length - 1);
    }
}

Then you can call it like so:

Debug.Print(BitConverter.ToString(net.PhysicalAddress));