C / C++ / MFC

Re: How to read the characters in the EditTable of SysListView32 style control ?

22-Oct-09 7:08

Assuming you have the window handle of the control, first send it a LVM_GETITEMCOUNT message. Then for each item, send the control a LVM_GETITEMTEXT message.

rand094122-Oct-09 15:01

rand0941

22-Oct-09 15:01

this item has two windows,you can find the editbox's handle to read text from it.

Re: How to read the characters in the EditTable of SysListView32 style control ?

nenfa19-Jan-10 0:21

nenfa

19-Jan-10 0:21

do you have happen this problem:

str1's content is equivalent to str2，str3,str4 and str5,how to solve the problem, thank you very much.

DeviceIoControl to lock drive is not working

Patcher3222-Oct-09 5:09

22-Oct-09 5:09

Okay I am trying to lock CD drive (F: here) with the code shown. But DeviceIoControl is returning "error 87: Parameter not correct". Please someone help me. I cannot find out which parameter is incorrcet.

#include <windows.h>
#include <winioctl.h>
#include <stdio.h>

void ShowError(void); //function to display message from GetLastError()

int main(){
	char szVolume[] = "\\\\.\\F:";
	HANDLE hVolume;
	DWORD dwBytes = 0;
	PREVENT_MEDIA_REMOVAL pmr;

	pmr.PreventMediaRemoval = TRUE;

	hVolume = CreateFile(szVolume,GENERIC_READ|GENERIC_WRITE,FILE_SHARE_READ|FILE_SHARE_WRITE,NULL,OPEN_EXISTING,0,NULL);
	if(hVolume==INVALID_HANDLE_VALUE){
		ShowError();
		exit(1);
	}
	if(DeviceIoControl(hVolume,IOCTL_STORAGE_EJECTION_CONTROL,(LPVOID)&pmr,(DWORD)sizeof(pmr),NULL,0,&dwBytes,NULL)==FALSE){
		ShowError();
	}
	CloseHandle(hVolume);
	return 0;
}

Covean22-Oct-09 5:34

Covean

22-Oct-09 5:34

I can't find an error, but maybe you open the device in a wrong way?

MSDN says:
"hDevice [in]
A handle to the device. To obtain a device handle, call the CreateFile function.

Files must be opened with the FILE_READ_ATTRIBUTES access right. For more information, see File Security and Access Rights."

You try to open your device with generic read and write access.
Sorry buts the only thing I found, what could maybe explain this error.

Has hVolume the right value?
(Your check is right, but i wonder what GetLastError() says.)

Edit:
Maybe you should also change your sharing parameter in your CreateFile call (for example try 0 -> no share).

Patcher3222-Oct-09 13:12

22-Oct-09 13:12

Yes hVolume is right value. GetLastError returns 0.
GENERIC_READ already has FILE_READ_ATTRIBUTES
Tried using 0 for File sharing but still DeviceIoControl gives error 87 parameter not correct
Thanks for replying, I appreciate it.

Code-o-mat22-Oct-09 5:52

Code-o-mat

22-Oct-09 5:52

Are you completely sure about F:?

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Sometimes you just have to hate coding to do it well. <

Patcher3222-Oct-09 13:13

22-Oct-09 13:13

Yes my DVD drive is F:. and handle returned by CreateFile is valid too.
Thanks for replying

David Crow22-Oct-09 6:20

22-Oct-09 6:20

Patcher32 wrote:
PREVENT_MEDIA_REMOVAL pmr;

Isn't this used with IOCTL_STORAGE_MEDIA_REMOVAL?

Code-o-mat22-Oct-09 6:34

Code-o-mat

22-Oct-09 6:34

According to this[^] it is also used with IOCTL_STORAGE_EJECTION_CONTROL.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Sometimes you just have to hate coding to do it well. <

David Crow22-Oct-09 6:56

22-Oct-09 6:56

Two MSDN sites that contradict each other. No surprise there!

Patcher3222-Oct-09 13:44

22-Oct-09 13:44

Okay I finally got it to work. YAY! Smile | :)

I made this change : pmr.PreventMediaRemoval = (BYTE)TRUE; in the original code I posted.

But MSDN says the PreventMediaRemoval member is BOOLEAN? Thanks for confusing me MSDN! Mad | :mad:

The value has to be BYTE. So setting it to 1 locks drive from being ejected. Setting it to 0 unlocks the drive from ejecting.

Covean22-Oct-09 20:59

Covean

22-Oct-09 20:59

"But MSDN says the PreventMediaRemoval member is BOOLEAN? Thanks for confusing me MSDN!"

MSDN is right the problem is, that TRUE is a 32 Bit-Value (TRUE and true are not the same). So you send the value 0(FALSE) to your drive. And if I'm right, the function fails if you try to unlock drive you never locked before.

Patcher3223-Oct-09 19:22

Renaming file in C++ failing

23-Oct-09 19:22

If I lock with (BYTE)TRUE : works
If I unlock a locked device using (BYTE)FALSE : works
If I try to unlock a device (without locking it first) using (BYTE)FALSE : gives error #22, The device does not recognize command

I think this is expected behavior. Please guide me in right direction if I am doing it wrong.

StrayGrey22-Oct-09 3:58

22-Oct-09 3:58

I have a C++ program running on Windows XP compiled with Visual C++ 6.0 containing the following code
[code]
if (remove(NewName) != 0)
{
errmsg = strerror(errno);
printf("Removal Error: %s\n", errmsg);
}

if (rename(FileName,NewName) != 0)
{
errmsg = strerror(errno);
printf("Rename Error: %s\n", errmsg);
}
[/code]

and this fails, offering to send a message to Microsoft about the error of my ways.
The file I want to rename(FileName) does exist and the file I want to rename it to(NewName) does not and none of my error messages appear.
Please make suggestions on how I should fix this.

Regards,
Alf Stockton

David Crow22-Oct-09 4:06

22-Oct-09 4:06

StrayGrey wrote:
if (remove(NewName) != 0)

What does remove() return?

StrayGrey wrote:
errmsg = strerror(errno);

How is errmsg declared?

Hve you tried DeleteFile() or SHFileOperation()?

StrayGrey22-Oct-09 4:20

22-Oct-09 4:20

I apparently do not get anything back from remove()

errmsg is defined as
char *errmsg;

Regards,
Alf Stockton

Michael Schubert22-Oct-09 4:12

Michael Schubert

22-Oct-09 4:12

Have you used the debugger? What types are NewName and FileName?

StrayGrey22-Oct-09 4:17

22-Oct-09 4:17

I have them defined as:-
char *FileName = "";

char *NewName = "";

Regards,
Alf Stockton

Michael Schubert22-Oct-09 4:22

Michael Schubert

22-Oct-09 4:22

Again, have you used the debugger? Do FileName and NewName contain valid file names (and paths)?

StrayGrey22-Oct-09 5:08

22-Oct-09 5:08

The trick that has worked for me is not to define the file names as pointers but rather as arrays.

Regards,
Alf Stockton

David Crow22-Oct-09 6:05

22-Oct-09 6:05

Whether you use

char *NewName = "c:\\somefile.txt";
remove(NewName);

char NewName[] = "c:\\somefile.txt";
remove(NewName);

they both work.