Question

我目前正在尝试使用wlanapi.dll WlanQueryInterface调用从无线接入点检索信号强度。

这是我的api声明

    [DllImport("wlanapi.dll", SetLastError = true)]
private static extern UInt32 WlanQueryInterface(IntPtr hClientHandle, ref Guid pInterfaceGuid, WLAN_INTF_OPCODE OpCode, IntPtr pReserved, out Int32 pdwDataSize, ref IntPtr ppData, IntPtr pWlanOpCodeValueType);

问题是，当我查看WLAN_ASSOCIATION_ATTRIBUTES结构中的wlanSignalStrength条目时，它被设置为5400. Microsoft API文档说它应该是0到100之间的值。

这是我的结构声明：

    /// <summary>
/// Structure contains association attributes for a connection.
/// </summary>
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
private struct WLAN_ASSOCIATION_ATTRIBUTES
{
    /// <summary>
    /// A DOT11_SSID structure that contains the SSID of the association.
    /// </summary>
    public DOT11_SSID dot11Ssid;
    /// <summary>
    /// A DOT11_BSS_TYPE value that specifies whether the network is infrastructure or ad hoc.
    /// </summary>
    public DOT11_BSS_TYPE dot11BssType;
    /// <summary>
    /// A DOT11_MAC_ADDRESS that contains the BSSID of the association.
    /// </summary>
    public DOT11_MAC_ADDRESS dot11Bssid;
    /// <summary>
    /// A DOT11_PHY_TYPE value that indicates the physical type of the association
    /// </summary>
    public DOT11_PHY_TYPE dot11PhyType;
    /// <summary>
    /// The position of the DOT11_PHY_TYPE value in the structure containing the list of PHY types.
    /// </summary>
    public ulong uDot11PhyIndex;
    /// <summary>
    /// A percentage value that represents the signal quality of the network.
    /// </summary>
    public Int32 wlanSignalQuality;
    /// <summary>
    /// Contains the receiving rate of the association.
    /// </summary>
    public ulong ulRxRate;
    /// <summary>
    /// Contains the transmission rate of the association.
    /// </summary>
    public ulong ulTxRate;
}

这是我对WlanQueryInterface的调用：

    Int32 iDataSize;
    IntPtr ppData = IntPtr.Zero;
    WLAN_CONNECTION_ATTRIBUTES wcaAttributes = new WLAN_CONNECTION_ATTRIBUTES();
    String[] sReturn = new String[4];

    if (WlanQueryInterface(pClientHandle, ref gInterfaceGUID, WLAN_INTF_OPCODE.wlan_intf_opcode_current_connection, IntPtr.Zero, out iDataSize, ref ppData, IntPtr.Zero) == ERROR_SUCCESS)
    {
        wcaAttributes = (WLAN_CONNECTION_ATTRIBUTES)Marshal.PtrToStructure(ppData, typeof(WLAN_CONNECTION_ATTRIBUTES));

        sReturn[0] = wcaAttributes.wlanAssociationAttributes.dot11Ssid.ucSSID;
        sReturn[1] = wcaAttributes.strProfileName;
        sReturn[2] = String.Format("{0:X2}-{1:X2}-{2:X2}-{3:X2}-{4:X2}-{5:X2}", wcaAttributes.wlanAssociationAttributes.dot11Bssid.bOne, wcaAttributes.wlanAssociationAttributes.dot11Bssid.bTwo, wcaAttributes.wlanAssociationAttributes.dot11Bssid.bThree, wcaAttributes.wlanAssociationAttributes.dot11Bssid.bFour, wcaAttributes.wlanAssociationAttributes.dot11Bssid.bFive, wcaAttributes.wlanAssociationAttributes.dot11Bssid.bSix);
        sReturn[3] = wcaAttributes.wlanAssociationAttributes.wlanSignalQuality.ToString(); //This returns 5400 when the actual strength is ~99

        WlanFreeMemory(ppData);

        return sReturn;
    }
    else
    {
        throw new Exception("Unable to get interface connected SSID.");
    }

有谁看到我做错了什么？提前谢谢！

Answer 1

我终于修好了。我必须将WLAN_ASSOCIATION_ATTRIBUTES的LayoutKind设置为Explicit，并将charset设置为Unicode。

    [StructLayout(LayoutKind.Explicit, CharSet = CharSet.Unicode)]
private struct WLAN_ASSOCIATION_ATTRIBUTES
{
    /// <summary>
    /// A DOT11_SSID structure that contains the SSID of the association.
    /// </summary>
    [FieldOffset(0)]
    public DOT11_SSID dot11Ssid;
    /// <summary>
    /// A DOT11_BSS_TYPE value that specifies whether the network is infrastructure or ad hoc.
    /// </summary>
    [FieldOffset(0x24)]
    public DOT11_BSS_TYPE dot11BssType;
    /// <summary>
    /// A DOT11_MAC_ADDRESS that contains the BSSID of the association.
    /// </summary>
    [FieldOffset(40)]
    public DOT11_MAC_ADDRESS dot11Bssid;
    /// <summary>
    /// A DOT11_PHY_TYPE value that indicates the physical type of the association
    /// </summary>
    [FieldOffset(0x30)]
    public DOT11_PHY_TYPE dot11PhyType;
    /// <summary>
    /// The position of the DOT11_PHY_TYPE value in the structure containing the list of PHY types.
    /// </summary>
    [FieldOffset(0x34)]
    public ulong uDot11PhyIndex;
    /// <summary>
    /// A percentage value that represents the signal quality of the network.
    /// </summary>
    [FieldOffset(0x38)]
    public Int32 wlanSignalQuality;
    /// <summary>
    /// Contains the receiving rate of the association.
    /// </summary>
    [FieldOffset(60)]
    public ulong ulRxRate;
    /// <summary>
    /// Contains the transmission rate of the association.
    /// </summary>
    [FieldOffset(0x40)]
    public ulong ulTxRate;
}

C＃wlanapi.dll问题接收信号强度

1 个答案: