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C# problem using the GetVersionExA API.

Hi.
I'm trying to determine if the operating system is a domain controller using the GetVersionExA function and OSVERSIONINFOEX struct
I tried the exact same code in VB.NET and it worked just fine, but it doesn't in C#.
Any ideas?

Here is the code I have:
[StructLayout(LayoutKind.Sequential)]
public struct OSVERSIONINFOEX
{
      [MarshalAs(UnmanagedType.U4)]
      public int dwOSVersionInfoSize;
      [MarshalAs(UnmanagedType.U4)]
      public int dwMajorVersion;
      [MarshalAs(UnmanagedType.U4)]
      public int dwMinorVersion;
      [MarshalAs(UnmanagedType.U4)]
      public int dwBuildNumber;
      [MarshalAs(UnmanagedType.U4)]
      public int dwPlatformId;
      [MarshalAs(UnmanagedType.LPTStr, SizeConst=128)]
      public string szCSDVersion;
      [MarshalAs(UnmanagedType.U2)]
      public short wServicePackMajor;
      [MarshalAs(UnmanagedType.U2)]
      public short wServicePackMinor;
      [MarshalAs(UnmanagedType.U2)]
      public short wSuiteMask;
      public byte wProductType;
      public byte wReserved;
}

[DllImport("kernel32.dll", SetLastError = true)]
public static extern bool GetVersionExA([MarshalAs(UnmanagedType.Struct)] ref OSVERSIONINFOEX lpVersionInfo);

public bool IsDomainController()
{
bool isDC = false;
OSVERSIONINFOEX os = new OSVERSIONINFOEX();
os.dwOSVersionInfoSize = Marshal.SizeOf(os);
if (GetVersionExA(ref os))
{
      isDC = (os.wProductType == 2);
}
else
{
      Marshal.ThrowExceptionForHR(Marshal.GetHRForLastWin32Error());
}

return isDC;
}

Any help would be greatly appreciated!

Bob Learned

Try something like this instead:

string osVersion = Environment.OSVersion.Platform.ToString();

Bob

Balder1978

ASKER

I don't need the OS version, I need to know if it's a Domain Controller or not.
But thanks for the input!

Bob Learned

Do you still have the VB.NET code?

Bob

Balder1978

ASKER

sure:

<StructLayout(LayoutKind.Sequential)> _
Public Structure OSVERSIONINFOEX
<MarshalAs(UnmanagedType.U4)> _
Public dwOSVersionInfoSize As Integer
<MarshalAs(UnmanagedType.U4)> _
Public dwMajorVersion As Integer
<MarshalAs(UnmanagedType.U4)> _
Public dwMinorVersion As Integer
<MarshalAs(UnmanagedType.U4)> _
Public dwBuildNumber As Integer
<MarshalAs(UnmanagedType.U4)> _
Public dwPlatformId As Integer
<MarshalAs(UnmanagedType.ByValArray, SizeConst:=128)> _
Public szCSDVersion() As Char
<MarshalAs(UnmanagedType.U2)> _
Public wServicePackMajor As Short
<MarshalAs(UnmanagedType.U2)> _
Public wServicePackMinor As Short
<MarshalAs(UnmanagedType.U2)> _
Public wSuiteMask As Short
Public wProductType As Byte
Public wReserved As Byte
End Structure

Private Declare Function GetVersionEx Lib "kernel32.dll" Alias "GetVersionExA" (<MarshalAs(UnmanagedType.Struct)> ByRef ByReflpVersionInfo As OSVERSIONINFOEX) As Boolean

Usage:
Dim os As OSVERSIONINFOEX = New OSVERSIONINFOEX
os.dwOSVersionInfoSize = Marshal.SizeOf(os)
GetVersionEx(os)

Bob Learned

In VB.NET, the os.dwOSVersionInfoSize = 156, and in C#, it is 32. Investigating...

Bob

Balder1978

ASKER

Exactly, and if I set it manually to 156 (which is too dirty programming), I get the OS version numbers, but not the wProductType wich is what I'm looking for.
Thanks!

Bob Learned

The OSVERSIONINFOEX.szCSDVersion appears to be the problem.

In the VB.NET IL code:

szCSDVersion public marshal (fixed array[128]) char[]

In the C# IL code:

szCSDVersion public marshal (lptstr) string

There is clearly a size difference here.

Bob

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Bob Learned

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Balder1978

ASKER

that didn't work, but this did:

[MarshalAs(UnmanagedType.ByValTStr, SizeConst=128)]
public string szCSDVersion;

The size is now 156, but it still doesn't work...

Bob Learned

It worked for me--return a false. What .NET version do you have? I have 2003.

Bob

Balder1978

ASKER

I have 2003 with .NET 1.1 SP1 too... Strange...

Bob Learned

What happened when you used this?

[MarshalAs(UnmanagedType.ByValArray , SizeConst=128)]
public char[] szCSDVersion;

Bob

Balder1978

ASKER

So sorry, didn't change public char[] szCSDVersion;
I'll test it and get back to u ASAP.

Balder1978

ASKER

Thanks alot, man. Works great!