Directories of removable disk Using DiretoryInfo

Akemi Chou

12y1.9kVisual Basic .NET

Hi Programmers, can you help me on how can i get the directories of a certain flash drive using DirectoryInfo in C#?

7 Replies

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Vulpes12y ago
You didn't say which line was causing the error but, if the variable 'drive' is still null, that can only mean that the flash drive is not plugged in or is plugged in but isn't yet ready to be read.

You can guard against this error by changing the code to the following:

private button1_Click(object sender, EventArgs e)
{
string drive = null;

foreach (DriveInfo d in DriveInfo.GetDrives())
{
if (d.IsReady && d.VolumeLabel == "FLASHY) // or whatever
{
drive = d.Name;
break;
}
}

if (drive != null)
{
foreach(string dir in Directory.GetDirectories(drive))
{
listBox1.Items.Add(Path.GetFileName(dir));
}
}
else
{
MessageBox.Show("Flash drive is not plugged in or is not yet ready");
}

}
Akemi Chou12y ago
"Value cannot be null." There should be value :(
Vulpes12y ago
Well, I just used a console app for simplicity to illustrate the code, but you can easily put it into a Windows Forms app. For example:

using System.IO;

// ...

private button1_Click(object sender, EventArgs e)
{
string drive = null;

foreach (DriveInfo d in DriveInfo.GetDrives())
{
if (d.IsReady && d.VolumeLabel == "FLASHY) // or whatever
{
drive = d.Name;
break;
}
}

foreach(string dir in Directory.GetDirectories(drive))
{
listBox1.Items.Add(Path.GetFileName(dir));
}
}

Although it's possible to create or amend a volume label programatically, I'd do it instead from the command prompt using the LABEL statement.
Akemi Chou12y ago
But I am using Windows form of C#, how could I do that? :)
Vulpes12y ago
If no other removable drive will be plugged in at the same time as your flash drive, then you could use this revised code to identify its drive letter and hence enumerate its directories:

using System;
using System.IO;

class Test
{
static void Main()
{
string drive = null;

foreach (DriveInfo d in DriveInfo.GetDrives())
{
if (d.IsReady && d.DriveType == DriveType.Removable)
{
drive = d.Name;
break;
}
}

foreach(string dir in Directory.GetDirectories(drive))
{
Console.WriteLine(Path.GetFileName(dir));
}
Console.ReadKey();
}
}

Otherwise, the only thing I can think of is to give it a unique Volume Label and then identify it from that:

foreach (DriveInfo d in DriveInfo.GetDrives())
{
if (d.IsReady && d.VolumeLabel == "FLASHY) // or whatever
{
drive = d.Name;
break;
}
}

If the flash drive doesn't have a unique volume label already, then you can give it one with the LABEL command:

http://en.wikipedia.org/wiki/Label_(command)
Akemi Chou12y ago
I am so sorry for the inadequate and unspecific question. However, thanks for your answer but my point is, I wanted that the program will detect the certain flash drive without changing the location of a file because there are some instances that the Drive letter of some other removable disks are not permanent. Example of it; there are some which was located for I: or K: or G:.

The question is; how can I make it default or let's just say the system could easily identify without mapping it manually with the use of DirectoryInfo? thanks for your reply :)
Vulpes12y ago
As long as the flash drive is mapped to a drive letter, then you should be able to get a list of its directories in the same way as you would for a 'fixed' drive:

using System;
using System.IO;

class Test
{
static void Main()
{
string drive = "F:"; // say

foreach(string dir in Directory.GetDirectories(drive))
{
Console.WriteLine(Path.GetFileName(dir));
}
Console.ReadKey();
}
}