P/从WlanHostedNetworkQueryStatus调用wlanapi.dll

Question

我已经映射了C++函数(来自WLanapi.dll)：

    DWORD WINAPI WlanHostedNetworkQueryStatus(
      _In_        HANDLE hClientHandle,
      _Out_       PWLAN_HOSTED_NETWORK_STATUS *ppWlanHostedNetworkStatus,
      _Reserved_  PVOID pvReserved
    );

到以下C#代码：

    [DllImport("Wlanapi.dll", SetLastError = true)]
    static extern UInt32 WlanHostedNetworkQueryStatus(
        [In] IntPtr hClientHandle,
        [Out] out _WLAN_HOSTED_NETWORK_STATUS ppWlanHostedNetworkStatus,
        [In, Out] IntPtr pvReserved
        );

我还映射了所需的所有结构和枚举以及其他东西(例如，获取clientHandle指针和启动托管网络)。

_WLAN_HOSTED_NETWORK_STATUS的映射如下：

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
    public struct _WLAN_HOSTED_NETWORK_STATUS
    {
        public _WLAN_HOSTED_NETWORK_STATE HostedNetworkState;
        public Guid IPDeviceID;
        public _DOT11_MAC_ADDRESS wlanHostedNetworkBSSID;
        public _DOT11_PHY_TYPE dot11PhyType;
        public UInt32 ulChannelFrequency;
        public UInt32 dwNumberOfPeers;
        public _WLAN_HOSTED_NETWORK_PEER_STATE[] PeerList;
    }

现在，在执行该函数时，我不知道如何正确地使用ppWlanHostedNetworkStatus等等。函数返回ERROR_SUCCESS (0)，这意味着我已经正确地调用并传递了参数：

    _WLAN_HOSTED_NETWORK_STATUS netStatus = new _WLAN_HOSTED_NETWORK_STATUS();

    WlanHostedNetworkQueryStatus(clientHandle, out netStatus, IntPtr.Zero);

但是，在查询ppWlanHostedNetworkStatus的值(比如网络的状态或连接的对等点的数量)时，我只得到了一些奇怪的长整数(我可以说是内存地址，但我不确定)，例如：

netStatus.HostedNetworkState.ToString();

返回

11465720

HostedNetworkState是定义如下的枚举：

    public enum _WLAN_HOSTED_NETWORK_STATE
    {
        wlan_hosted_network_unavailable,
        wlan_hosted_network_idle,
        wlan_hosted_network_active
    }

所以.toString()应该从枚举返回其中一个字符串，对吗？

我很确定这与指针等有关，因为在_WLAN_HOSTED_NETWORK_STATUS ( MS文档 )的文档中，它说在调用该函数之前，ppWlanHostedNetworkStatus应该是NULL，并且它本身就是指向结构的指针.

我如何调试它？我正在用C#编码，VS 2012.

谢谢你的帮助。

-编辑-编辑

我进一步尝试用IntPtr映射函数作为参数，传递IntPtr.Zero和Marshal.PtrToStruct，但是当我试图这样做的时候，会得到AccessViolationException .

    [DllImport("Wlanapi.dll", SetLastError = true)]
    static extern UInt32 WlanHostedNetworkQueryStatus(
        [In] IntPtr hClientHandle,
        [Out] out IntPtr ppWlanHostedNetworkStatus,
        [In, Out] IntPtr pvReserved
        );

然后：

    IntPtr ppStatus = IntPtr.Zero;

    WlanHostedNetworkQueryStatus(clientHandle, out ppStatus, IntPtr.Zero);

    _WLAN_HOSTED_NETWORK_STATUS netStatus = (_WLAN_HOSTED_NETWORK_STATUS)Marshal.PtrToStructure(ppStatus, typeof(_WLAN_HOSTED_NETWORK_STATUS));

编辑2

按照Fermat2357的建议，我取消了要映射的结构体的注释部分，并将以下内容更改为计数指向指针的指针：

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
    public struct _WLAN_HOSTED_NETWORK_STATUS
    {
        public _WLAN_HOSTED_NETWORK_STATE HostedNetworkState;
        public Guid IPDeviceID;
        public _DOT11_MAC_ADDRESS wlanHostedNetworkBSSID;
        public _DOT11_PHY_TYPE dot11PhyType;
        public UInt32 ulChannelFrequency;
        public UInt32 dwNumberOfPeers;
        //public _WLAN_HOSTED_NETWORK_PEER_STATE[] PeerList;
    }

我这样叫它：

    IntPtr ppStatus = IntPtr.Zero;
    WlanHostedNetworkQueryStatus(clientHandle, out ppStatus, IntPtr.Zero);
    IntPtr ppStatus2 = new IntPtr(ppStatus.ToInt32());
    _WLAN_HOSTED_NETWORK_STATUS stat = (_WLAN_HOSTED_NETWORK_STATUS)Marshal.PtrToStructure(ppStatus2, typeof(_WLAN_HOSTED_NETWORK_STATUS));
    netStatus = stat.HostedNetworkState.ToString();

这最终给出了正确的网络状态(启动后激活).现在我得想办法整理那个动态数组..。

到目前为止谢谢您的帮助Fermat2357

Answer 1

编辑:我要尝试的一件事是我用来帮助调试的技巧--用字节数组替换您的结构，并查看您拉回的内容(好的，在本例中是uint数组)：

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct _WLAN_HOSTED_NETWORK_STATUS
{
    [MarshalAs(UnmanagedType.ByValArray, ArraySubType=UnmanagedType.U4, SizeConst = 48)]
    public uint[] scratch;
}

但是，当我在本地运行这个值时，我得到了非常奇怪的值--第一个(10x4) =40个字节被归零：

0 0 0 0 
0 0 0 0 
0 0 4D454D4C 28 
16DCD870 0 787F6447 80000020 
...omitted...

尝试这组P/Invoke声明：

(在LINQPad中完成，因此相应地替换"Dump“方法)

void Main()
{
    IntPtr clientHandle;
    int negotiatedVersion;
    if(WlanOpenHandle(2, IntPtr.Zero, out negotiatedVersion, out clientHandle) != 0)
    {
        throw new InvalidOperationException("Could not open handle");
    }
    Console.WriteLine("Negotiated version:{0}", negotiatedVersion);
    IntPtr pNetStatus = IntPtr.Zero;
    if(WlanHostedNetworkQueryStatus(clientHandle, out pNetStatus, IntPtr.Zero) != 0)
    {
        throw new InvalidOperationException("Could not query network status");
    }
    var netStatus = (WLAN_HOSTED_NETWORK_STATUS)Marshal.PtrToStructure(pNetStatus, typeof(WLAN_HOSTED_NETWORK_STATUS));
    Console.WriteLine(netStatus.PeerList[0]);
    WlanFreeMemory(pNetStatus);
    WlanCloseHandle(clientHandle, IntPtr.Zero);
}


[DllImport("Wlanapi.dll", SetLastError = true)]
[return:MarshalAs(UnmanagedType.Bool)]
public static extern bool WlanOpenHandle(
  [In] int dwClientVersion,
  IntPtr pReserved,
  [Out] out int pdwNegotiatedVersion,
  [Out] out IntPtr phClientHandle
);
[DllImport("Wlanapi.dll", SetLastError = true)]
[return:MarshalAs(UnmanagedType.Bool)]
public static extern bool WlanCloseHandle(
  [In] IntPtr hClientHandle,
  IntPtr pReserved
);
[DllImport("Wlanapi.dll", SetLastError = true)]
static extern UInt32 WlanHostedNetworkQueryStatus(
    [In] IntPtr hClientHandle,
    [Out] out IntPtr ppWlanHostedNetworkStatus,
    [In, Out] IntPtr pvReserved
);

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct _WLAN_HOSTED_NETWORK_STATUS
{
    public _WLAN_HOSTED_NETWORK_STATE HostedNetworkState;
    public Guid IPDeviceID;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst=6)]
    public string wlanHostedNetworkBSSID;
    public _DOT11_PHY_TYPE dot11PhyType;
    public UInt32 ulChannelFrequency;
    public UInt32 dwNumberOfPeers;
    public IntPtr PeerList;
}
public enum _WLAN_HOSTED_NETWORK_STATE 
{ 
  wlan_hosted_network_unavailable,
  wlan_hosted_network_idle,
  wlan_hosted_network_active
}
public enum _DOT11_PHY_TYPE : uint
{ 
  dot11_phy_type_unknown     = 0,
  dot11_phy_type_any         = 0,
  dot11_phy_type_fhss        = 1,
  dot11_phy_type_dsss        = 2,
  dot11_phy_type_irbaseband  = 3,
  dot11_phy_type_ofdm        = 4,
  dot11_phy_type_hrdsss      = 5,
  dot11_phy_type_erp         = 6,
  dot11_phy_type_ht          = 7,
  dot11_phy_type_IHV_start   = 0x80000000,
  dot11_phy_type_IHV_end     = 0xffffffff
}
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct _WLAN_HOSTED_NETWORK_PEER_STATE 
{
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst=6)]
    public string PeerMacAddress;
    _WLAN_HOSTED_NETWORK_PEER_AUTH_STATE PeerAuthState;
}
public enum _WLAN_HOSTED_NETWORK_PEER_AUTH_STATE 
{ 
  wlan_hosted_network_peer_state_invalid,
  wlan_hosted_network_peer_state_authenticated
}