private static bool GetProcessElevated()
{
    IntPtr tokenHandle;
    if (!OpenProcessToken(Process.GetCurrentProcess().Handle, TOKEN_READ, out tokenHandle))
        throw new ApplicationException("Could not get process token. Win32 Error Code: " + Marshal.GetLastWin32Error());

    TOKEN_ELEVATION_TYPE elevationResult = TOKEN_ELEVATION_TYPE.TokenElevationTypeDefault;

    int elevationResultSize = Marshal.SizeOf((int)elevationResult);
    uint returnedSize = 0;
    IntPtr elevationTypePtr = Marshal.AllocHGlobal(elevationResultSize);

    bool success = GetTokenInformation(tokenHandle, TOKEN_INFORMATION_CLASS.TokenElevationType, elevationTypePtr, (uint)elevationResultSize, out returnedSize);
    if (!success)
        throw new ApplicationException("Unable to get process elevation info.");

    elevationResult = (TOKEN_ELEVATION_TYPE)Marshal.ReadInt32(elevationTypePtr);
    bool elevated = elevationResult == TOKEN_ELEVATION_TYPE.TokenElevationTypeFull;
    return elevated;
}

private static uint STANDARD_RIGHTS_READ = 0x00020000;
private static uint TOKEN_QUERY = 0x0008;
private static uint TOKEN_READ = (STANDARD_RIGHTS_READ | TOKEN_QUERY);

[DllImport("advapi32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool OpenProcessToken(IntPtr ProcessHandle, UInt32 DesiredAccess, out IntPtr TokenHandle);

[DllImport("advapi32.dll", SetLastError = true)]
public static extern bool GetTokenInformation(IntPtr TokenHandle, TOKEN_INFORMATION_CLASS TokenInformationClass, IntPtr TokenInformation, uint TokenInformationLength, out uint ReturnLength);

#region Enums

public enum TOKEN_INFORMATION_CLASS
{
    TokenUser = 1,
    TokenGroups,
    TokenPrivileges,
    TokenOwner,
    TokenPrimaryGroup,
    TokenDefaultDacl,
    TokenSource,
    TokenType,
    TokenImpersonationLevel,
    TokenStatistics,
    TokenRestrictedSids,
    TokenSessionId,
    TokenGroupsAndPrivileges,
    TokenSessionReference,
    TokenSandBoxInert,
    TokenAuditPolicy,
    TokenOrigin,
    TokenElevationType,
    TokenLinkedToken,
    TokenElevation,
    TokenHasRestrictions,
    TokenAccessInformation,
    TokenVirtualizationAllowed,
    TokenVirtualizationEnabled,
    TokenIntegrityLevel,
    TokenUIAccess,
    TokenMandatoryPolicy,
    TokenLogonSid,
    MaxTokenInfoClass
}

public enum TOKEN_ELEVATION_TYPE
{
    TokenElevationTypeDefault = 1,
    TokenElevationTypeFull,
    TokenElevationTypeLimited
}

#endregion Enums