C# Definition:
/// <summary>
/// Contains an array of NIC information
/// </summary>
[StructLayout(LayoutKind.Sequential)]
public struct WLAN_INTERFACE_INFO_LIST
{
/// <summary>
/// Length of <see cref="InterfaceInfo"/> array
/// </summary>
public Int32 dwNumberOfItems;
/// <summary>
/// This member is not used by the wireless service. Applications can use this member when processing individual interfaces.
/// </summary>
public Int32 dwIndex;
/// <summary>
/// Array of WLAN interfaces.
/// </summary>
public WLAN_INTERFACE_INFO[] InterfaceInfo;
/// <summary>
/// Constructor for WLAN_INTERFACE_INFO_LIST.
/// Constructor is needed because the InterfaceInfo member varies based on how many adapters are in the system.
/// </summary>
/// <param name="pList">the unmanaged pointer containing the list.</param>
public WLAN_INTERFACE_INFO_LIST(IntPtr pList)
{
// The first 4 bytes are the number of WLAN_INTERFACE_INFO structures.
dwNumberOfItems = Marshal.ReadInt32(pList, 0);
// The next 4 bytes are the index of the current item in the unmanaged API.
dwIndex = Marshal.ReadInt32(pList, 4);
// Construct the array of WLAN_INTERFACE_INFO structures.
InterfaceInfo = new WLAN_INTERFACE_INFO[dwNumberOfItems];
for (int i = 0; i <= dwNumberOfItems - 1; i++) {
// The offset of the array of structures is 8 bytes past the beginning.
// Then, take the index and multiply it by the number of bytes in the
// structure.
// The length of the WLAN_INTERFACE_INFO structure is 532 bytes - this
// was determined by doing a Marshall.SizeOf(WLAN_INTERFACE_INFO)
IntPtr pItemList = new IntPtr(pList.ToInt64() + (i * 532) + 8);
// Construct the WLAN_INTERFACE_INFO structure, marshal the unmanaged
// structure into it, then copy it to the array of structures.
InterfaceInfo[i] = (WLAN_INTERFACE_INFO)Marshal.PtrToStructure(pItemList, typeof(WLAN_INTERFACE_INFO));
}
}
}
VB Definition:
<StructLayout(LayoutKind.Sequential)> _
Private Structure WLAN_INTERFACE_INFO_LIST
Public dwNumberofItems As Int32
Public dwIndex As Int32
Public InterfaceInfo As WLAN_INTERFACE_INFO()
Public Sub New(pList As IntPtr)
' The first 4 bytes are the number of WLAN_INTERFACE_INFO structures.
dwNumberofItems = Marshal.ReadInt32(pList, 0)
' The next 4 bytes are the index of the current item in the unmanaged API.
dwIndex = Marshal.ReadInt32(pList, 4)
' Construct the array of WLAN_INTERFACE_INFO structures.
InterfaceInfo = New WLAN_INTERFACE_INFO(dwNumberofItems - 1) {}
For i As Integer = 0 To dwNumberofItems - 1
' The offset of the array of structures is 8 bytes past the beginning.
' Then, take the index and multiply it by the number of bytes in the
' structure.
' The length of the WLAN_INTERFACE_INFO structure is 532 bytes - this
' was determined by doing a Marshall.SizeOf(WLAN_INTERFACE_INFO)
Dim pItemList As New IntPtr(pList.ToInt64() + (i * 532) + 8)
' Construct the WLAN_INTERFACE_INFO structure, marshal the unmanaged
' structure into it, then copy it to the array of structures.
InterfaceInfo(i) = DirectCast(Marshal.PtrToStructure(pItemList, GetType(WLAN_INTERFACE_INFO)), WLAN_INTERFACE_INFO)
Next
End Sub
End Structure
User-Defined Field Types:
Notes:
The constructor of this structure "unmarshal" WLAN_INTERFACE_INFO_LIST data obtained by calling WlanEnumInterfaces(). This is a good example on how to marshal pointer-to-pointer case in C++ world ( kind of confusing because in C# or Managed Environment more broadly, it is just reference, so as you can see from the implementation for C#, it is to be treated like just a single pointer case. Also, this example shows how to handle an array for the InterfaceInfo inside of this structure. It needs two level of marshaling and this example shows that.
