Lazarus

Programming => General => Topic started by: jarmo.kervinen@elisanet.f on January 14, 2020, 05:12:12 pm

Title: How to detect unmounted drive from ShellTreeView before Error
Post by: jarmo.kervinen@elisanet.f on January 14, 2020, 05:12:12 pm

My ShellTreeView vindow shows in the start of program signs of all drives (C:\ ...E:\).
Drive E is not mounted. If I click it, it raises Error (32 bit Windows 7). In other PC (64 bit Windows 7) No error appears.
How to detect in OnEnter or by signing in  ShellTreeView, that some drive in unmounted?
Jarmo Kervinen

Title: Re: How to detect unmounted drive from ShellTreeView before Error
Post by: Bart on January 14, 2020, 06:12:02 pm

This may help?

Code: Pascal  [Select][+][-]

1. uses
2.   Windows;
3.  
4. function DiskInDrive(Drive: Char): Boolean;
5. var
6.   ErrorMode: word;
7. begin
8.   { maak er een hoofdletter van }
9.   Drive := UpCase(Drive);
10.   if not (Drive in ['A'..'Z']) then
11.     raise EConvertError.Create('Geen geldige stationsaanduiding: '+Drive+':');
12.   { schakel kritieke fouten uit }
13.   ErrorMode := SetErrorMode(SEM_FailCriticalErrors);
14.   try
15.     { drive 1 = a, 2 = b, 3 = c, etc. }
16.     if DiskSize(Ord(Drive) - Ord('A') + 1) = -1 then
17.       Result := False
18.     else
19.       Result := True;
20.   finally
21.     { restore old error mode }
22.     SetErrorMode(ErrorMode);
23.   end;
24. end;

It's Windows only of course, so you'll have to ifdef it.

Bart

Title: Re: How to detect unmounted drive from ShellTreeView before Error
Post by: Thaddy on January 14, 2020, 06:46:41 pm

@Bart
That works for local drives only.
You also have to account for canonical paths.

Title: Re: How to detect unmounted drive from ShellTreeView before Error
Post by: Bart on January 14, 2020, 10:48:59 pm

Quote from: Thaddy on January 14, 2020, 06:46:41 pm

You also have to account for canonical paths.

Huh?
What is that and would that show up as a drive letter in a TShellTreeView?
(The question was about drives in a TShellTreeView)

Bart

Title: Re: How to detect unmounted drive from ShellTreeView before Error
Post by: jarmo.kervinen@elisanet.f on January 15, 2020, 09:33:23 am

Thank you Bert. The solution was critical in my program.
Jarmo

Title: Re: How to detect unmounted drive from ShellTreeView before Error
Post by: Bart on January 15, 2020, 03:30:21 pm

Quote from: jarmo.kervinen@elisanet.f on January 15, 2020, 09:33:23 am

Thank you Bert.

Bert and Ernie are from Sesamestreet.
I share my name with one of the Simpsons  (I would have preferred that Ernie's friend were called Bart though)O:-)

Glad to be of help though.

Bart