The statement of netCfgLock.AcquireWriteLock(ms, desc1, desc2) gives me an
error saying "Object reference not set to an instance of an object." However,
if I comment this line out, line 2 and line 3 both can be executed
successfully. So I think the problem is those three paramenters of ms, desc1,
and desc2. The following is from Microsoft,
HRESULT AcquireWriteLock(IN DWORD cmsTimeout, IN LPCWSTR
pszwClientDescription, OUT LPWSTR *ppszwClientDescription);
I think that the third parameter should be a pointer to string string, but
how can I pass in a pointer to string in C#?
Thanks for you help. (following is the code)
[Guid("C0E8AE9F-306E-11D1-AACF-00805FC1270E"),
InterfaceType(ComInterfaceType.InterfaceIsIUnknown )]
[ComVisible(true)]
interface INetCfgLock
{
int AcquireWriteLock([In, MarshalAs(UnmanagedType.I8)] ulong
cmsTimeout,
[In, MarshalAs(UnmanagedType.LPWStr)] string pszwClientDescription,
[Out, MarshalAs(UnmanagedType.LPWStr)] string ppszwClientDescription);
int ReleaseWriteLock();
int IsWriteLocked([Out, MarshalAs(UnmanagedType.LPWStr)] string
ppszwClientDescription);
};
object objINetCfgLock = null;
int _nRet = 0;
_nRet = Ole32Methods.CoCreateInstance(ref INetCfg_Guid.CLSID_CNetCfg,
null, Ole32Methods.CLSCTX_INPROC_SERVER, ref
INetCfg_Guid.IID_INetCfgLockClass, out objINetCfgLock);
objINetCfgLock.GetType();
INetCfgLock netCfgLock = objINetCfgLock as INetCfgLock;
if (netCfgLock != null)
{
ulong ms = 500;
string desc1 = "NETCONN";
string desc2 = string.Empty;
netCfgLock.AcquireWriteLock(ms, desc1, desc2); //Line 1
netCfgLock.ReleaseWriteLock(); //Line 2
_nRet = netCfgLock.IsWriteLocked(desc1); //Line 3
}
