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Hi,
I have been searching for several hours about how to get a list of all drive letters in use. All of the code examples I have tried were able to list all drive letters in use but did not include mapped network drives.
I have tried DriveInfo, Directory.GetLogicalDrives and attempted to use WMI through the ManagementObjectSearcher. Win32_DiskDrive and Win32_LogicalDisk lists all drives except mapped network drives. If I use Win32_NetworkConnection or Win32_MappedLogicalDrive using Scriptomatic, only the network drive is listed but when those WMI classes are in my C# code, nothing seems to happen with my application. No output is ever produced.
There is some conversation around the Win32 API but 100+ lines of code seems a bit overkill to map a single drive unless that is the only way it can be done.
A few others mentioned not to use 'NET USE' so I have avoided that in favor of using a native C# code. I want to follow C# best practices as closely as possible.
Ultimately I would like to use the next available drive letter to map to a network share but I need some way to be certain that the next available drive letter is not in use by a network share that the methods I have been using cannot see. I haven't found any complete code in one place (or even across many places) that can accomplish this.
Thanks,
Rob
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Um.
string[] drives = Environment.GetLogicalDrives();
foreach (string drive in drives)
{
Console.WriteLine(drive);
}
For me that prints:
A:\
B:\
C:\
D:\
E:\
F:\
G:\
M:\
P:\
S:\
V:\
X:\
Z:\ Where C: is my primary HDD Partition; D: is my secondary; E:, F:, and G: are my DVD drive in various forms; Z: is a USB drive; and all the rest are network shares.
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Environment.GetLogicalDrives is not collecting my network drive as far as I can tell. The only output I am getting are all physical drives. My output is:
C:\
D:\
E:\
F:\
G:\
H:\
I:\
K:\
There should be an X:\ drive listed for my my network drive. I don't have a clue why it works for you but the same snippet works differently for me. I'll try inspecting the array during debug to see if it was collected but is not getting output for some reason.
UPDATE: I checked the 'drives' array during debug and my X:\ is not a member.
-Rob
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Is the drive connected and readable? What does Windows Explorer say?
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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I can see that drive X:\ is available in File Explorer (Win 8.1) and I can access it without any issues. As I mentioned in my first post, Win32_NetworkConnect and Win32_MappedLogicalDrive give me the mapped network drives in vbscript but I can't seem to get these WMI Classes to work with the C# ManagementObjectSearcher.
I'm leaning towards using Environment.GetLogicalDrives, get the last drive letter used and then use Try-Catch to map the next drive letter. If the mapping fails because it's a network drive, I'm not sure where to go from there.
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Friend I do a project in C#.I am new to C#.I need to know about:
1)How to plot the real time data that come every second from com port into the Graph
2)Running on the low priority thread,that logs data into table for that day in DB(MySQL) should store one day data
next day clean the old data and store current Data only.I am unable to rectify that Problem.Please give me solution for that.
Thank you for Reading
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This is a broad concept and might require me to forward you to some other resources to learn more on these facilities. For example, the first thing is creating charts is itself a broad thing to do and mostly you might require a third-party library to create charts in your C# application. You forgot to mention which framework you're going to use, WPF or Win Forms etc.
You can however, try to do a little Google for this chart library and Google would yield a lot of friendly results for you to use any of those libraries. Try out this Google search[^] (chart C#).
Once that has been done the other thing that you've said about constantly updating the chart requires you to run a function (for creating the chart) after every instance of time (which in your case, might be a function call, a time interval like 1 second, or any other condition or event) to let your chart get updated every time there is a new data. It totally depends on your application and how you implement this updating-the-UI-feature. An example of such might be using the Timer class, to run your application after a time interval. But what I would like to advise here would be to run your application, each time a new data is saved in the database. Create a function like StoreData() and then inside this function, run other function to update the chart. This would save you time, and would cause the application to update its UI only when a new data is added.
If you want to delete the data from MySQL database, you can simply pass the command of DELETE to the data source (server) and it would delete all of the data. Otherwise, if you're going to delete the data from the thread only, then you can try to create a new instance of that thread every day and so on.
The sh*t I complain about
It's like there ain't a cloud in the sky and it's raining out - Eminem
~! Firewall !~
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Too much for a quick answer, but we can give you some first steps. Try that and come back with more specific problems when needed.
First of all, if you're a beginner you're probably in over your head, if you have a senior developer to ask questions to, do that.
Secondly, you'll need to divide your problem into smaller problems. for instance you could separate your data to graph problem by creating a module that reads the com port and just saves the data to database. A second problem would then be to read the data from database and put into a graph. A third, again separate module would check which data should be removed and removes it.
Make sure to use a layered and modular approach. Take in account risks (what happens if data could not be read from com port, or removed the next day? What happens if one of the modules falls out, ...).
With that in mind, steer away from any IDE you're using and start opening up documents to create a good design:
- what are the object definitions and how are they moved around both in database as in code?
- what are the possible modules and what are there tasks?
- Who can use which part of the system?
- What technologies will you use for the graph system (some prototyping will need to be done)
- Try to imagine how the system would grow.
- What exceptions or problems could arise?
- ...
good luck.
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Hi!
In my base class I want a "constant" FUNC_LENGTH that I assign at creation of my first object. I´d like to have it static. So I tried this:
public abstract class Package
{
private static readonly int funcLength;
protected static int FUNC_LENGTH { get {return funcLength;} }
static Package(int _funcLength)
{
funcLength = _funcLength;
}
public Package() {}
...
}
Obviously this wont work, since a static constructor wont take any parameters. Does this mean it is impossible to make FUNC_LENGTH static?
I read in a book that the static constructor is run once "before first use", does that mean it runs when (or immediately before) the first instance of the class is created?
modified 12-Jan-15 3:01am.
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What you probably want is a Singleton design: see here[^]
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No, I dont think so. My class is an abstract base class (I just updated the code above). So I will actually have several instances of this class subclasses. Its part of a communication protocol, so I want to define this specific package field size (FUNC_LENGTH) before creation of the first package. After that there must not be any way to change that size, or the communication will break down.
The singleton is, as I know it, a class that can only have one single instance. Correct me if Im wrong.
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ok, I misunderstood, I would probably have a private static boolean that indicates if the func_length was set or not. In that case you may pass anything you want, but only the first will update the property.
I'm sure there are better solutions, but I think it would work and it is pretty simple.
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Snap! 
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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I swear I didn't see your reply 
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Didn't think you did!
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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It's not impossible, but it is nasty. Very nasty!
As you say, you can't have a static constructor with a parameter - because static constructors are never called from your code directly, but by the system immediately prior to the first instance being created, so it can't call a parametrized one. So it has to be a parameter to an instance constructor: which means a check is needed:
public abstract class Package
{
protected static int FUNC_LENGTH { get; private set; }
private static bool onceAlready = false;
public Package(int _funcLength)
{
if (!onceAlready)
{
FUNC_LENGTH = _funcLength;
onceAlready = true;
}
}
...
}
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Depending on where you're getting the value to set funcLength to, maybe you could read it from a config inside the static constructor?
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A config file would work, of course, but the value wont ever change between compilations. It seems more streamlined to just set it via the constructor when creating the package factory class. Then the factory class will pass it to the package instances.
I guess a static boolean would work, just thought there would be a more slick way to do it (I actually have more than one of those "constants").
Maybe I just skip the static part. Feels like a defeat though.
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If the value wont' change between compilations, why not just make it a const value? They are effectively static anyway. Or is it a complex calculation that has to be done at run time? You can't do it as a "prebuild step" or similar? I do something similar to that to time stamp assemblies with the build date / time: Timestamping assemblies with Build date and time.[^]
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Uhm, didnt think of a const being static, but of course you´re right on that one. Great, const it is!
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Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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I was too quick there. This is a lib, so when using this lib by creating a Package object, you will pass the value into its constructor. So I cant use a const here.
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So it's not fixed at compile time - and you're back to a static bool I'm afraid!
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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