dcsimg
Login | Register   
RSS Feed
Download our iPhone app
TODAY'S HEADLINES  |   ARTICLE ARCHIVE  |   FORUMS  |   TIP BANK
Browse DevX
Sign up for e-mail newsletters from DevX

By submitting your information, you agree that devx.com may send you DevX offers via email, phone and text message, as well as email offers about other products and services that DevX believes may be of interest to you. DevX will process your information in accordance with the Quinstreet Privacy Policy.


Tip of the Day
Language: Pascal
Expertise: Beginner
Nov 4, 1998

WEBINAR:

On-Demand

Application Security Testing: An Integral Part of DevOps


Error Checking Using DriveComboBox Component

Question:
I am finding it difficult to check whether an error has occurred in selecting a drive when it is not available at the time. I have tried to use IOResult when the change event takes place, but it doesn't seem to work. The error that occurs is I/O result 21. IOResult works with other I/O errors that occur, such as "file not found," but using IOResult with a component like DriveComboBox doesn't work. I would appreciate if you could help me solve this problem.

Answer:
One way that I've found that works is to use the Windows API call GetVolumeInformation to test if a drive is ready. GetVolumeInformation will retrieve information like serial numbers and disk capacities. If GetVolumeInformation can read a drive it returns true, otherwise it returns false. I've written a wrapper function that will help you out with your problem:

{=================================================
This checks the drive to see if it's ready. If
GetVolumeInformation returns false, the drive isn't ready.

Value of Drv formal parameter should be something
like: 'C:\' or 'F:\'
=================================================}
function CheckDriveOK(Drv : String) : Boolean; 
var
  //Volume Information Variables
  nVNameSer   : PDWORD;
  pVolName    : PChar;
  FSSysFlags,
  maxCmpLen   : DWord;
  pFSBuf      : PChar;
begin
  //initialize vars
  GetMem(pVolName, MAX_PATH);
  GetMem(pFSBuf, MAX_PATH);
  GetMem(nVNameSer, MAX_PATH);

  //Now, get the volume information
  Result := GetVolumeInformation(PChar(drv), 
             pVolName, MAX_PATH, nVNameSer,
             maxCmpLen, FSSysFlags, pFSBuf, 
             MAX_PATH);
end;
DevX Pro
 
Comment and Contribute

 

 

 

 

 


(Maximum characters: 1200). You have 1200 characters left.

 

 

Sitemap
×
We have made updates to our Privacy Policy to reflect the implementation of the General Data Protection Regulation.
Thanks for your registration, follow us on our social networks to keep up-to-date