How to set up C# structures for WlanHostedNetworkSetProperty function

Question

From the Microsoft Documentation:

DWORD WINAPI WlanHostedNetworkSetProperty(
  _In_       HANDLE                      hClientHandle,
  _In_       WLAN_HOSTED_NETWORK_OPCODE  OpCode,
  _In_       DWORD                       dwDataSize,
  _In_       PVOID                       pvData,
  _Out_opt_  PWLAN_HOSTED_NETWORK_REASON pFailReason,
  _Reserved_ PVOID                       pvReserved
);

My implementation

     [DllImport("Wlanapi.dll", EntryPoint = "WlanHostedNetworkSetProperty")]
        public static extern uint WlanHostedNetworkSetProperty(
             IntPtr hClientHandle,
             WLAN_HOSTED_NETWORK_OPCODE OpCode,
             uint dwDataSize,
             IntPtr pvData,
             [Out] out WLAN_HOSTED_NETWORK_REASON pFailReason,
             IntPtr pReserved
        );

This works fine if I am only trying to enable or disable Wlan. However when I try to set the ssid and the numbers of peers I am running into an error because pvData needs to be a pointer to the following struct:

From Microsoft Documentation:

typedef struct _WLAN_HOSTED_NETWORK_CONNECTION_SETTINGS {
  DOT11_SSID hostedNetworkSSID;
  DWORD      dwMaxNumberOfPeers;
} WLAN_HOSTED_NETWORK_CONNECTION_SETTINGS, *PWLAN_HOSTED_NETWORK_CONNECTION_SETTINGS;

and

typedef struct _DOT11_SSID {
  ULONG uSSIDLength;
  UCHAR ucSSID[DOT11_SSID_MAX_LENGTH];
} DOT11_SSID, *PDOT11_SSID;

This is my implementation of both structures:

    public struct WLAN_HOSTED_NETWORK_CONNECTION_SETTINGS
    {
        public DOT11_SSID hostedNetworkSSID;
        public UInt32 dwMaxNumberOfPeers;
    }

    public struct DOT11_SSID 
    {
        public UInt32 uSSIDLength;
        public byte[] ucSSID;
    }

Finally, this is how I am making the call:

            APCreator.WLAN_HOSTED_NETWORK_CONNECTION_SETTINGS networkSetting = new APCreator.WLAN_HOSTED_NETWORK_CONNECTION_SETTINGS();
            networkSetting.dwMaxNumberOfPeers = 5;
            networkSetting.hostedNetworkSSID = new APCreator.DOT11_SSID();
            networkSetting.hostedNetworkSSID.ucSSID = new byte[10];
            //Populate ucSSID with network name

            networkSetting.hostedNetworkSSID.uSSIDLength = 10;


            int size = Marshal.SizeOf(networkSetting);
            IntPtr pNetworkSetting = Marshal.AllocHGlobal(size);
            Marshal.StructureToPtr(networkSetting, pNetworkSetting, true);
            APCreator.WlanHostedNetworkSetProperty(HANDLE, APCreator.WLAN_HOSTED_NETWORK_OPCODE.wlan_hosted_network_opcode_connection_settings, (uint)size, pNetworkSetting, out ReasonEnum, Nill).ToString();

Error reason returns with: wlan_hosted_network_reason_isufficient_resources

The question is: How to set up those structures?

vcsjones · Accepted Answer · 2015-10-02T17:28:42.587

1

Your DOT11_SSID struct is incorrect. Try this:

public struct DOT11_SSID
{
    public UInt32 uSSIDLength;
    [MarshalAs(UnmanagedType.ByValArray, SizeConst = DOT11_SSID_MAX_LENGTH)]
    public byte[] ucSSID;
}

Without the MarshalAs attribute, it's trying to marshal the ucSSID field as a pointer to a byte array rather than including the value with the struct.

Replace DOT11_SSID_MAX_LENGTH with whatever value is defined in the header.

edited Oct 02 '15 at 17:28

answered Oct 02 '15 at 17:14

vcsjones

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That little tidbit was hard to find – TsSkTo Oct 02 '15 at 17:36

How to set up C# structures for WlanHostedNetworkSetProperty function

1 Answers1