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
    );

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内容（例如，获取clientHandle指针并启动托管网络）。
_WLAN_HOSTED_NETWORK_STATUS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;
    }

现在执行该功能时，我不确定如何正确使用ppWlanHostedNetworkStatus等。该函数返回ERROR_SUCCESS（0），这意味着我已经调用它并正确地传递参数：

    _WLAN_HOSTED_NETWORK_STATUS netStatus = new _WLAN_HOSTED_NETWORK_STATUS();

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

但是在查询ppWlanHostedNetworkStatus的值时（比如网络状态或连接对等体的数量）我只得到一些奇怪的长整数（我会说内存地址，但我不确定），例如调用：

netStatus.HostedNetworkState.ToString();

返回

11465720

HostedNetworkState是一个枚举，定义如下：

    public enum _WLAN_HOSTED_NETWORK_STATE
    {
        wlan_hosted_network_unavailable,
        wlan_hosted_network_idle,
        wlan_hosted_network_active
    }

所以.toString（）应该从枚举中返回其中一个字符串，对吧？我很确定它与指针等有关，因为在_WLAN_HOSTED_NETWORK_STATUS（MS documentation）的文档中，它说在调用该函数之前，ppWlanHostedNetworkStatus应该是NULL，并且它本身是一个指向结构的指针......

我该如何调试？我在C＃编写，VS 2012 ...

感谢您的帮助。

- - - - - - - - EDIT
我进一步尝试使用IntPtr作为参数映射函数，传递IntPtr.Zero和Marshal.PtrToStruct，但是在尝试这样做时我得到了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 -------

根据Fermat2357的建议，我已经取消注释要映射的结构部分，并更改以下内容以计算指向指针的指针：

    [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;
    }

我称之为：

    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();

这最终给了我正确的网络状态（启动后激活）...现在我必须找到一种方法来编组动态数组...
到目前为止，感谢Fermat2357的帮助

Answer 1

您的映射不正确。看一下API函数WlanHostedNetworkQueryStatus的定义。

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

请注意，参数ppWlanHostedNetworkStatus是指向WLAN_HOSTED_NETWORK_STATUS结构指针的指针。深入了解您将找到的功能文档

ppWlanHostedNetworkStatus [out]

输入时，此参数必须为NULL。

在输出时，如果对WlanHostedNetworkQueryStatus函数的调用成功，则此参数接收指向无线托管网络当前状态的指针。当前状态以WLAN_HOSTED_NETWORK_STATUS结构返回。

如果您提供NULL指针（如文档中所述），则底层API将为您保留结构并初始化指向此缓冲区的指针。后来不要忘记通过拨打WlanFreeMemory来释放它。否则你会在这里泄漏资源。

然而，该功能的文档似乎并非100％完整。在我的测试（Win7 32Bit）中，如果您将指针指向足够大的内存缓冲区，API将不会为您分配内存。在这种情况下，稍后调用WlanFreeMemory似乎没有必要。但在这种情况下，很难猜出以下WLAN_HOSTED_NETWORK_PEER_STATE结构需要多少内存。因此，这似乎无论如何都不可用。

这是我用于测试的C代码

#include <Wlanapi.h>

int _tmain(int argc, _TCHAR* argv[])
{
    DWORD dwRes;
    HANDLE hHandle;
    DWORD negotiatedVersion;

    dwRes = WlanOpenHandle(1, NULL, &negotiatedVersion, &hHandle);
    if (ERROR_SUCCESS == dwRes)
    {
        PWLAN_HOSTED_NETWORK_STATUS pStatus = NULL;

        dwRes = WlanHostedNetworkQueryStatus(hHandle, &pStatus, NULL);
        if (ERROR_SUCCESS == dwRes)
        {
            if (wlan_hosted_network_unavailable != pStatus->HostedNetworkState)
            {
                // Do something with the result
            }

            WlanFreeMemory(pStatus);
        }
        else
        {
            // handle Error
        }

        WlanCloseHandle(hHandle, NULL);
    }
    else
    {
        // handle Error
    }

    return 0;
}

如果你想让你的样本工作，你需要修改你整理结构的方式。

修改

要正确编组，您可以尝试以下操作：

... [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 _WLAN_HOSTED_NETWORK_PEER_STATE PeerList; } ... IntPtr ptr = new IntPtr(); uint hostedNetworkQueryStatusSuccess = WlanHostedNetworkQueryStatus(clientHandle, out ptr, IntPtr.Zero); if (openHandleSuccess == 0) { var netStat = (_WLAN_HOSTED_NETWORK_STATUS)Marshal.PtrToStructure(ptr, typeof(_WLAN_HOSTED_NETWORK_STATUS)); Console.WriteLine(netStat.HostedNetworkState); if (netStat.HostedNetworkState != _WLAN_HOSTED_NETWORK_STATE.wlan_hosted_network_unavailable) { IntPtr offset = Marshal.OffsetOf(typeof(_WLAN_HOSTED_NETWORK_STATUS), "PeerList"); for (int i = 0; i < netStat.dwNumberOfPeers; i++) { var peer = (_WLAN_HOSTED_NETWORK_PEER_STATE)Marshal.PtrToStructure( new IntPtr(ptr.ToInt64() + offset.ToInt64()), typeof(_WLAN_HOSTED_NETWORK_PEER_STATE)); System.Console.WriteLine(peer.PeerMacAddress); offset += Marshal.SizeOf(peer); } } }

想法：我在这里使用一个结构，我可以确定它一直在正确地编组。稍后了解dwNumberOfPeers成员（如果它有效）我会逐步获得所有内部结构。

Answer 2

编辑：要尝试的一件事是我用来帮助调试的技巧 - 用字节数组替换你的结构，并看看你撤回了什么（好吧，在这种情况下是一个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;
}

当我在本地运行时，我得到非常奇怪的值，但是 - 第一个（10x4）= 40个字节被清零：

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，所以相应地替换“转储”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
}

P /从Wlanapi.dll调用WlanHostedNetworkQueryStatus

2 个答案: