|
I need to display a huge size file(1GB) content in a dialog, when it is popup to the user. I tried to read the file content in oninitdialog(), but since huge size, dialog takes some more time to display. Is there any other way to read and display the file content with minimum time?
Kindly help me asap!
|
|
|
|
|
You can use overlapped or asynchronous read operations on the file.
This way you can initiate the read from OnInitDialog where the read function will immediately return and complete later.
Read about it here - Synchronous and Asynchronous I/O[^]
|
|
|
|
|
Thanks a lot Superman. But Is it possible to do it in any other function excluding oninitdialog()? This is just my doubt.
|
|
|
|
|
If you're using overlapped/asynchronous file read, you could initiate it in the constructor of your dialog class or globally when the program is started.
You can also create a new thread in which the file read can be done.
In this case you will have to device a communication mechanism using messages so that the thread can notify the main UI thread of the completion of the read and pass the buffer containing the contents of the file.
|
|
|
|
|
Thanks for your inputs! But my requirement is to display whole file content. Anyway superman idea is apt for my query.
|
|
|
|
|
Prabhu092009 wrote: But my requirement is to display whole file content
Wow, your users really want to look at over 1 gig of data ?
Anyway, whatever the method you use, reading 1gig+ from the disk is going to take some time anyway, not only reading the file, but allocating the memory to hold that data; and probably will crash the application because the control you will use to display the data will not work with that amount of data.
Maybe have look at memory mapped files ?Watched code never compiles.
|
|
|
|
|
Why possibly would you display the whole file content?
Just use paging as suggested and display only what's actually visible. Why don't you understand it?!
“Follow your bliss.” – Joseph Campbell
|
|
|
|
|
Since you cannot display the whole file content (I suppose), why don't you load just the needed part?
 If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
|
|
|
|
|
DeviceIoControl with IOCTL_DISK_GET_DRIVE_LAYOUT parameter does not returns correct values for drives in dynamic disk. For basic disk all values are correct.
DWORD i;
HANDLE handle = CreateFile("\\.\PhysicalDrive0", ,GENERIC_READ,FILE_SHARE_READ|FILE_SHARE_WRITE,0,OPEN_EXISTING,0,0);
DRIVE_LAYOUT_INFORMATION *drive_layout;
int buf_size = sizeof(DRIVE_LAYOUT_INFORMATION) + 8* sizeof(PARTITION_INFORMATION);
DeviceIoControl(handle,IOCTL_DISK_GET_DRIVE_LAYOUT,NULL,0,(BYTE*)drive_layout,buf_size,&i,NULL);
for (i = 0; i < drive_layout->PartitionCount; i++)
{
PARTITION_INFORMATION * partinfo = &drive_layout->PartitionEntry[i];
// PARTITION_INFORMATION keeps starting offset, drive size and hidden sectors for any drive. and i can get all using partinfo pointer.
}
If i have a disk of 80 gb size. Suppose First drive (C:/) start at sector 63 and size is 20 gb, then second drive (d:/) start at offset 40 gb and size is 20 gb then above function returns 20 gb as start offset for second drive. While the correct value is 40 gb. (In this disk offset from 20 gb to 40 gb is free and it has no partition).
I also tried to open second drive (CreateFile("\\.\d:",..) and call DeviceIoControl with IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS parameter but it does not returns correct value for starting offset and drive size.
Please suggest.
|
|
|
|
|
Hi all,
I want to read the datas in a CSV file line by line.How can i do this? Can anyone please help me?
Thanks,
|
|
|
|
|
CSV is a text file.
If you're using MFC, use the CStdioFile class and its ReadString method to read it line by line.
Or you can use std::ifstream to open the file for reading and then use the getline function to read line by line.
|
|
|
|
|
|
|
Hi,Im using WPF as C# dll in VC++.Im sending datas to the Listbox inthe third tabitem in a tabcontrol by using this coding.
void CToolTab::SendPresetmenu(CString menu)
{
FrameworkElement^ page;
String ^ msg = gcnew String( menu );
Globals1::gwpreset->AddPresetmenu(msg);
page = Globals1::gwpreset;
Globals1::gHwndSource->RootVisual = page;
}
By this code,wat happend is my entire tabcontrol becomes a third tab item.there is not other tabs .
If i commented those last two bolded line.Full tabcotrol appears correctly but the listbox doesnot contain text.
How can i do that?Anu
|
|
|
|
|
Why don't you post it in the appropriate forum [^]?
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
|
|
|
|
|
Hi All
I am using copy command to join two files. It works fine when I am using this in the command prompt
But I want to run this command in the background using vc++. so please tell me how I run this command in the background.
copy /b "first file path"+"second file path" "outfilepath"
|
|
|
|
|
You can use the system function to execute the command.
But it is preferable to use the file operation APIs like CreateFile and WriteFile to achieve the same.
|
|
|
|
|
Thanks for reply
I try system command Its working fine but the command window is show.
I want also hide this command window.
actually i am joining mp3 file so thats why i am using copy command.
|
|
|
|
|
To hide the command window you will have to do a lot more work.
You will need to use CreateProcess to start the command prompt (Cmd.exe) and specifying CREATE_NO_WINDOW in the dwCreationFlags parameter.
If this doesn't work you can set the STARTF_USESHOWWINDOW flag in the STARTUPINFO structure and set its wShowWindow member to SW_HIDE.
The copy command will need to be given as parameter to the Cmd.exe.
Instead it will be easier to use the file APIs like CreateFile and WriteFile.
|
|
|
|
|
Now I tried this
char cmdpath[MAX_PATH] ={0};
cmdpath = "copy /b firstfilepath+secondfilepath outfilepath "
CreateProcessA("cmd.exe", cmdpath, NULL, NULL, FALSE,NULL DETACHED_PROCESS , NULL, NULL, &sInfo, &pInfo);
but this is not joining the file
|
|
|
|
|
cmd.exe itself has some command line parameters that you need to specify to execute internal commands.
|
|
|
|
|
raj1576 wrote: cmdpath = "copy /b firstfilepath+secondfilepath outfilepath "
This will not work. You either need to initialize cmdpath with this string literal, or use strcpy()."One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Man who follows car will be exhausted." - Confucius
|
|
|
|
|
I dont think its better to use copy command, instead use Copy file API( [^])
Well if you still want to stick with your choice then :-
1. Use CreateProcess
use CreateProcess with second parameter is command line argument([^]), where there is a optional structure STARTINFO([^]), having the wShowWindow to show or hide the window.
2. Use ShellExecute([^])
Eg:-
NT/2k/XP/2k3
ShellExecute( NULL, "open", "cmd.exe /C \"DEL /f /s /q c:\\check\\*\"", NULL, NULL, SW_HIDE );
Win9x
ShellExecute( NULL, "open", "command.com /C \"DEL /f /s /q c:\\check\\*\"", NULL, NULL, SW_HIDE ); Величие не Бога может быть недооценена.
|
|
|
|
|
Thanks for reply
can u explain how i use this copy command use in the shellexecute
copy /b "firstfile.mp3"+"secondfile.mp3" "outputfile.mp3"
|
|
|
|
|
I don't think you can merge MP3 files like that, they both have their own headers describing how is the data encoded (for example, you have 1 mp3 @ 320kbps and 1 mp3 @ 160kbps, what should the file be at the end ?)
You will have to convert that to WAV, and then you will be able to copy one WAV at the end of the other and after that reconvert to MP3 (and loosing precision and data in all the conversions).
M.Watched code never compiles.
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
