/// <summary>
/// 当设备插入或拔出时请求接收消息
/// Requests to receive a notification when a device is attached or removed.
/// </summary>
/// <param name="devicePathName"> 设备句柄 handle to a device. </param>
/// <param name="formHandle"> 接收事件的窗体句柄 handle to the window that will receive device events. </param>
/// <param name="classGuid"> 设备接口 GUID device interface GUID. </param>
/// <param name="deviceNotificationHandle"> 返回设备事件句柄 returned device notification handle. </param>
/// <returns>
/// 成功返回True
/// </returns>
public Boolean RegisterForDeviceNotifications(String devicePathName, IntPtr formHandle, Guid classGuid, ref IntPtr deviceNotificationHandle)
{
// A DEV_BROADCAST_DEVICEINTERFACE header holds information about the request.
DeviceManagementDeclarations.DEV_BROADCAST_DEVICEINTERFACE devBroadcastDeviceInterface = new DeviceManagementDeclarations.DEV_BROADCAST_DEVICEINTERFACE();
IntPtr devBroadcastDeviceInterfaceBuffer = IntPtr.Zero;
Int32 size = 0;
try
{
// Set the parameters in the DEV_BROADCAST_DEVICEINTERFACE structure.
// Set the size.
size = Marshal.SizeOf(devBroadcastDeviceInterface);
devBroadcastDeviceInterface.dbcc_size = size;
// Request to receive notifications about a class of devices.
devBroadcastDeviceInterface.dbcc_devicetype = DeviceManagementDeclarations.DBT_DEVTYP_DEVICEINTERFACE;
devBroadcastDeviceInterface.dbcc_reserved = 0;
// Specify the interface class to receive notifications about.
devBroadcastDeviceInterface.dbcc_classguid = classGuid;
// Allocate memory for the buffer that holds the DEV_BROADCAST_DEVICEINTERFACE structure.
devBroadcastDeviceInterfaceBuffer = Marshal.AllocHGlobal(size);
// Copy the DEV_BROADCAST_DEVICEINTERFACE structure to the buffer.
// Set fDeleteOld True to prevent memory leaks.
Marshal.StructureToPtr(devBroadcastDeviceInterface, devBroadcastDeviceInterfaceBuffer, true);
// 调用API函数
deviceNotificationHandle = DeviceManagementDeclarations.RegisterDeviceNotification(formHandle, devBroadcastDeviceInterfaceBuffer, DeviceManagementDeclarations.DEVICE_NOTIFY_WINDOW_HANDLE);
Debug.WriteLine("在函数RegisterForDeviceNotifications中" + this.MyDebugging.ResultOfAPICall("RegisterDeviceNotification"));
// 从非管理的devBroadcastDeviceInterfaceBuffer数据块集合到受管理的devBroadcastDeviceInterface对象
// Marshal data from the unmanaged block devBroadcastDeviceInterfaceBuffer to the managed object devBroadcastDeviceInterface
Marshal.PtrToStructure(devBroadcastDeviceInterfaceBuffer, devBroadcastDeviceInterface);
if ((deviceNotificationHandle.ToInt32() == IntPtr.Zero.ToInt32()))
{
return(false);
}
else
{
return(true);
}
}
catch (Exception ex)
{
throw;
}
finally
{
if (devBroadcastDeviceInterfaceBuffer != IntPtr.Zero)
{
// 释放由AllocHGlobal函数分配的内存空间。 Free the memory allocated previously by AllocHGlobal.
Marshal.FreeHGlobal(devBroadcastDeviceInterfaceBuffer);
}
}
}
/// <summary>
/// Requests to stop receiving notification messages when a device in an
/// interface class is attached or removed.
/// </summary>
/// <param name="deviceNotificationHandle"> handle returned previously by
/// RegisterDeviceNotification. </param>
public void StopReceivingDeviceNotifications(IntPtr deviceNotificationHandle)
{
try
{
// 调用API函数
DeviceManagementDeclarations.UnregisterDeviceNotification(deviceNotificationHandle);
Debug.WriteLine("在函数StopReceivingDeviceNotifications中" + this.MyDebugging.ResultOfAPICall("UnregisterDeviceNotification"));
}
catch (Exception ex)
{
throw;
}
}
/// <summary>
/// Use SetupDi API functions to retrieve the device path name of an
/// attached device that belongs to a device interface class.
/// </summary>
/// <param name="myGuid"> an interface class GUID. </param>
/// <param name="devicePathName"> a pointer to the device path name of an attached device. </param>
/// <returns> True if a device is found, False if not</returns>
public Boolean FindDeviceFromGuid(System.Guid myGuid, ref String[] devicePathName)
{
Int32 bufferSize = 0;
IntPtr detailDataBuffer = IntPtr.Zero;
Boolean deviceFound;
IntPtr deviceInfoSet = new System.IntPtr();
Boolean lastDevice = false;
Int32 memberIndex = 0;
DeviceManagementDeclarations.SP_DEVICE_INTERFACE_DATA MyDeviceInterfaceData = new DeviceManagementDeclarations.SP_DEVICE_INTERFACE_DATA();
Boolean success;
try
{
// 调用API 函数
deviceInfoSet = DeviceManagementDeclarations.SetupDiGetClassDevs(ref myGuid, IntPtr.Zero, IntPtr.Zero, DeviceManagementDeclarations.DIGCF_PRESENT | DeviceManagementDeclarations.DIGCF_DEVICEINTERFACE);
Debug.WriteLine("在函数FindDeviceFromGuid中" + this.MyDebugging.ResultOfAPICall("SetupDiGetClassDevs"));
deviceFound = false;
memberIndex = 0;
// The cbSize element of the MyDeviceInterfaceData structure must be set to
// the structure's size in bytes.
// The size is 28 bytes for 32-bit code and 32 bits for 64-bit code.
MyDeviceInterfaceData.cbSize = Marshal.SizeOf(MyDeviceInterfaceData);
do
{
// Begin with 0 and increment through the device information set until no more devices are available.
// 调用API函数
success = DeviceManagementDeclarations.SetupDiEnumDeviceInterfaces(deviceInfoSet, IntPtr.Zero, ref myGuid, memberIndex, ref MyDeviceInterfaceData);
Debug.WriteLine("在函数FindDeviceFromGuid中" + this.MyDebugging.ResultOfAPICall("SetupDiEnumDeviceInterfaces"));
// Find out if a device information set was retrieved.
if (!success)
{
lastDevice = true;
}
else
{
// 调用API函数
success = DeviceManagementDeclarations.SetupDiGetDeviceInterfaceDetail(deviceInfoSet, ref MyDeviceInterfaceData, IntPtr.Zero, 0, ref bufferSize, IntPtr.Zero);
Debug.WriteLine("在函数FindDeviceFromGuid中" + this.MyDebugging.ResultOfAPICall("SetupDiGetDeviceInterfaceDetail"));
// 使用返回的缓冲区大小为SP_DEVICE_INTERFACE_DETAIL_DATA结构分配内存
detailDataBuffer = Marshal.AllocHGlobal(bufferSize);
// Store cbSize in the first bytes of the array. The number of bytes varies with 32- and 64-bit systems.
Marshal.WriteInt32(detailDataBuffer, (IntPtr.Size == 4) ? (4 + Marshal.SystemDefaultCharSize) : 8);
// 再次调用SetupDiGetDeviceInterfaceDetail 函数，这次传递一个指针给DetailDataBuffer，返回请求的缓冲区大小
success = DeviceManagementDeclarations.SetupDiGetDeviceInterfaceDetail(deviceInfoSet, ref MyDeviceInterfaceData, detailDataBuffer, bufferSize, ref bufferSize, IntPtr.Zero);
Debug.WriteLine("在函数FindDeviceFromGuid中" + this.MyDebugging.ResultOfAPICall("SetupDiGetDeviceInterfaceDetail"));
// 略过 cbsize (4 bytes) 以获得devicePathName的地址
IntPtr pDevicePathName = new IntPtr(detailDataBuffer.ToInt32() + 4);
// 获取devicePathName字符串.
devicePathName[memberIndex] = Marshal.PtrToStringAuto(pDevicePathName);
if (detailDataBuffer != IntPtr.Zero)
{
// 释放由 AllocHGlobal 分配的内存
Marshal.FreeHGlobal(detailDataBuffer);
}
deviceFound = true;
}
memberIndex++;
}while (!((lastDevice == true)));
return(deviceFound);
}
catch (Exception ex)
{
throw;
}
finally
{
// 调用API函数释放内存
if (deviceInfoSet != IntPtr.Zero)
{
DeviceManagementDeclarations.SetupDiDestroyDeviceInfoList(deviceInfoSet);
Debug.WriteLine("在函数FindDeviceFromGuid中" + this.MyDebugging.ResultOfAPICall("SetupDiDestroyDeviceInfoList"));
}
}
}
