U盘拔出，获取拔出的U盘的盘符..

[fangchao918628]

不需要通过前后比较....
当接收到拔出的消息后,怎么样获取拔出的U盘的盘符

[wangk]

WM_DEVICECHANGE的DBT_DEVICEREMOVECOMPLETE如果是DBT_DEVTYP_VOLUME的话，你得到盘符。

[许文君]

in your WM_DEVICECHANGE message handler, you can enum hardware to check if USB is plugged in or off.
//HOWTO: Enumerate Hardware Devices by Using SetupDi Calls Q259695

#include <stdio.h>
#include <windows.h>
#include <setupapi.h>
#include <devguid.h>
#include <regstr.h>
#pragma comment(lib,"Setupapi.lib")
void printdata(LPVOID pdata,DWORD datalen,DWORD type);

int main( int argc, char *argv[ ], char *envp[ ] )
{
HDEVINFO hDevInfo;
SP_DEVINFO_DATA DeviceInfoData;
DWORD i;

// Create a HDEVINFO with all present devices.
hDevInfo = SetupDiGetClassDevs(NULL,
0, // Enumerator
0,
DIGCF_PRESENT | DIGCF_ALLCLASSES );

if (hDevInfo == INVALID_HANDLE_VALUE)
{
// Insert error handling here.
return 1;
}

// Enumerate through all devices in Set.

DeviceInfoData.cbSize = sizeof(SP_DEVINFO_DATA);
for (i=0;SetupDiEnumDeviceInfo(hDevInfo,i,
&DeviceInfoData);i++)
{
DWORD DataT;
LPTSTR buffer = NULL;
DWORD buffersize = 0;

//
// Call function with null to begin with,
// then use the returned buffer size
// to Alloc the buffer. Keep calling until
// success or an unknown failure.
//
while (!SetupDiGetDeviceRegistryProperty(
hDevInfo,
&DeviceInfoData,
SPDRP_DEVICEDESC,
&DataT,
(PBYTE)buffer,
buffersize,
&buffersize))
{
if (GetLastError() ==
ERROR_INSUFFICIENT_BUFFER)
{
// Change the buffer size.
if (buffer) LocalFree(buffer);
buffer = (char*)LocalAlloc(LPTR,buffersize);
}
else
{
// Insert error handling here.
break;
}
}
printf("SPDRP_DEVICEDESC:[%s]\n",buffer);
if (buffer) LocalFree(buffer);

buffer =NULL;
buffersize=0;
while (!SetupDiGetDeviceRegistryProperty(
hDevInfo,
&DeviceInfoData,
SPDRP_LOCATION_INFORMATION,
&DataT,
(PBYTE)buffer,
buffersize,
&buffersize))
{
if (GetLastError() ==
ERROR_INSUFFICIENT_BUFFER)
{
// Change the buffer size.
if (buffer) LocalFree(buffer);
buffer = (char*)LocalAlloc(LPTR,buffersize);
}
else
{
// Insert error handling here.
break;
}
}
printf("SPDRP_LOCATION_INFORMATION:[%s]\n",buffer);
if (buffer) LocalFree(buffer);

buffer =NULL;
buffersize=0;
while (!SetupDiGetDeviceRegistryProperty(
hDevInfo,
&DeviceInfoData,
SPDRP_ADDRESS,
&DataT,
(PBYTE)buffer,
buffersize,
&buffersize))
{
if (GetLastError() ==
ERROR_INSUFFICIENT_BUFFER)
{
// Change the buffer size.
if (buffer) LocalFree(buffer);
buffer = (char*)LocalAlloc(LPTR,buffersize);
}
else
{
// Insert error handling here.
break;
}
}
printf("Length:%d,SPDRP_ADDRESS:",buffersize);
printdata(buffer,buffersize,DataT);
printf("\n");
if (buffer) LocalFree(buffer);

}


if ( GetLastError()!=NO_ERROR &&
GetLastError()!=ERROR_NO_MORE_ITEMS )
{
// Insert error handling here.
return 1;
}

// Cleanup
SetupDiDestroyDeviceInfoList(hDevInfo);

return 0;
}

void printdata(LPVOID pdata,DWORD datalen,DWORD type)
{
if(datalen<=0)
return;
switch(type)
{
case REG_DWORD:
{
PDWORD np=(PDWORD)pdata;
printf("REG_DWORD:%d",np[0]);
}
break;
case REG_SZ:
printf("REG_SZ:%d",(LPCTSTR)pdata);
break;
default:
printf("other format");
break;
}
}
//HOWTO: Force Reenumeration of a Device Tree From an Application Q259697


//after I connect usb harddisk to computer, the following is found
//Result:[USB Mass Storage Device]
//Result:[Disk drive]

//There are 2 usb port on my computer, I plug my removable disk into one port, I get the following result,
//SPDRP_DEVICEDESC:[USB Root Hub]
//SPDRP_LOCATION_INFORMATION:[(null)]
//Length:4,SPDRP_ADDRESS:REG_DWORD:0
//SPDRP_DEVICEDESC:[USB Mass Storage Device]
//SPDRP_LOCATION_INFORMATION:[ScanLogic USBIDE]
//Length:4,SPDRP_ADDRESS:REG_DWORD:1
//SPDRP_DEVICEDESC:[Disk drive]
//SPDRP_LOCATION_INFORMATION:[(null)]
//Length:4,SPDRP_ADDRESS:REG_DWORD:1
//when I plug removable usb harddisk into the other port, I get the following result
//SPDRP_DEVICEDESC:[USB Root Hub]
//SPDRP_LOCATION_INFORMATION:[(null)]
//Length:4,SPDRP_ADDRESS:REG_DWORD:0
//SPDRP_DEVICEDESC:[USB Mass Storage Device]
//SPDRP_LOCATION_INFORMATION:[ScanLogic USBIDE]
//Length:4,SPDRP_ADDRESS:REG_DWORD:2
//SPDRP_DEVICEDESC:[Disk drive]
//SPDRP_LOCATION_INFORMATION:[(null)]
//Length:4,SPDRP_ADDRESS:REG_DWORD:2
//unplug the usb removable disk, result is the following
//SPDRP_DEVICEDESC:[USB Root Hub]
//SPDRP_LOCATION_INFORMATION:[(null)]
//Length:4,SPDRP_ADDRESS:REG_DWORD:0

[jyh_baoding]

查WINDOWS驱动

[fangchao918628]

[Quote=引用 1 楼 wangk 的回复:]
WM_DEVICECHANGE的DBT_DEVICEREMOVECOMPLETE如果是DBT_DEVTYP_VOLUME的话，你得到盘符。
[/Quote]
没怎么看明白..
这个得到盘符是怎么得到的...还是不很清楚

[ziplj]

给你段代码 你就明白了

//截获U盘插入消息
LRESULT CFileRecoveryDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
{
	// TODO: 在此添加专用代码和/或调用基类
	if(message == WM_DEVICECHANGE)
	{
		UINT Event = (UINT) wParam;
		DWORD dwData = (DWORD) lParam;
		PDEV_BROADCAST_HDR pDev_Hdr = (PDEV_BROADCAST_HDR)lParam;

		switch(Event)
		{
		case(DBT_DEVICEARRIVAL):			
			switch(pDev_Hdr->dbch_devicetype)
			{
			case(DBT_DEVTYP_VOLUME):		//U盘插入消息
				GetAllDrives();				
				break;
			}
			break;

		case(DBT_DEVICEREMOVECOMPLETE):			
			switch(pDev_Hdr->dbch_devicetype)
			{
			case(DBT_DEVTYP_VOLUME):		//U盘拔出消息
				PDEV_BROADCAST_VOLUME   pDev_Vol   =   (PDEV_BROADCAST_VOLUME)pDev_Hdr; 
				//获取拔出U盘的盘符
				DWORD dwDrive = pDev_Vol->dbcv_unitmask;
				int i = 0;
				for (i = 0 ; i < 32 ; i++)
				{
					if (dwDrive & (1 << i) )	//找到第一个可用的逻辑盘符
						break;		
				}
				Delete_A_Drive('A' + i);
				break;
			}
			break;

		default:
			break;
		}
		return(0);
	}

	return CDialog::WindowProc(message, wParam, lParam);
}

Delete_A_Drive里面的参数就是盘符

[ziplj]

2L好歹在CSDN混了这么长时间 贴代码和新注册的怎么一点区别都没有 ?

[wangk]

晕

1.注册通知后得到WM_DEVICECHANGE消息通知

2.wParam==DBT_DEVICEREMOVECOMPLETE，lParam == DEV_BROADCAST_HDR *

3. DEV_BROADCAST_HDR.dbch_devicetype == DBT_DEVTYP_VOLUME时
lParam == DEV_BROADCAST_VOLUME *

这时候根据结构的就能计算出盘符。

[fangchao918628]

明白了....
谢谢各位