Concatenate strings, convert to ushort, compare against ushort

Question

So I have some constants:

const ushort _WIN32_WINNT_NT4 = 0x0400;
const ushort _WIN32_WINNT_WIN2K = 0x0500;
....

And then I have a major version number, minor version number, and service pack number, that, when you concatenate those together, it's the same as the number above - except 2 of them are int and one is a string. I can get them all into a string like this:

string version = majorVersion.ToString() + minorVersion.ToString() + sp;

For Windows 2000, this would look like "500". It "matches" the ushort, just without the 0x0.

What I'd like to do is hand off version to a function, as a ushort that returns the correct OS:

private static string WindowsVersion(ushort uniNum)
{
    switch (uniNum)
    {
        case _WIN32_WINNT_NT4:
            return "Windows NT 4.0";
        case _WIN32_WINNT_WIN2K:
            return "Windows 2000";
        ....
        default:
            return "Unknown OS version.";
    }
 }

The problem is, even if I do:

ushort uniNum = Convert.ToUInt16(version);

And say it sends it in as 500, the constant is 0x0500, so it never finds the OS and returns Unknown OS version, instead. When I debug and hover over _WIN32_WINNT_WIN2K, it's actually 1280 in decimal format. _WIN32_WINNT_NT4 is showing as 1024, so "400" would never match it.

And if I include the "0x0":

ushort uniNum = Convert.ToUInt16("0x0" + version);

It gives me an error that the input is in the incorrect format.

I'm probably missing something simple, but I can't find anything anywhere that's been helpful.

score 1 · Accepted Answer · answered Oct 19 '17 at 01:42

1

You already have the constants and they are hexadecimal. If you are getting 400 and 500 they are also hexadecimal, so replace:

ushort uniNum = Convert.ToUInt16(version);

with:

ushort uniNum = Convert.ToUInt16(version, 16);

answered Oct 19 '17 at 01:42

Oleg

6,124
2
23
40

Yes, exactly what I needed. Thanks a million! – vapcguy Oct 19 '17 at 01:53

score 0 · Answer 2 · answered Oct 19 '17 at 01:06

0

Your constant declaration's value is a hexadecimal literal expression:

const ushort _WIN32_WINNT_NT4 = 0x0400;

Where 0x0400 is equivalent to hex 400, decimal 1024. So basically, you're not comparing to 400 but to 1024.

Change your constant to be 400 if you'd like to compare against 400:

const ushort _WIN32_WINNT_NT4 = 400;

answered Oct 19 '17 at 01:06

Bas

26,772
8
53
86

Sorry, but I don't think this is possible as 1) then it's not a `ushort` anymore - might as well call them all `int`, 2) I don't have control over what comes back from the Microsoft function as to how it defines itself. – vapcguy Oct 19 '17 at 01:10
Also, if it were hex 400, the decimal would be 190, not 1024. I don't know how Visual Studio is getting 1024 for `0x0400`. – vapcguy Oct 19 '17 at 01:32

Concatenate strings, convert to ushort, compare against ushort

2 Answers2