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See my above post. No need to lock when closing and (as noted in my initial answer) use SerialPort::IsOpen() instead of your own member variable.
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I still prefer to have lock in OpenPort to avoid that exception you mention
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Locking protects only against simultaneous calls. Because serial ports are exclusive, they are usually opened only once from within the main thread. When doing so, you would never have the situation of simultaneous calls from within your app. But you may have other open errors that should be handled.
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To be honest, if I were doing this, I'd look at using a different architecture altogether because you're mixing a lot of responsibilities in your code here. What I would be tempted to go with is to have your API exposed so that you have separate writer and reader implementations, and the actual management of the port operation would be the responsibility of a completely separate class altogether. As I tend to compose objects together with IoC, I would constrain the port functionality to be container controlled so that all classes get the same instance and I would put the checking of the port along with its creation in there. I would also hide this as an internal implementation detail so you would have this as an internal interface with an internal implementation. That way, your client code only sees the separate reader and writer interfaces. Something like this internally:
internal interface IHaspPort
{
SerialPort Port { get; }
}
internal class HaspPort : IHaspPort
{
private readonly object SyncLock = new object();
private SerialPort port;
public SerialPort Port
{
get
{
if (port == null)
{
lock(SyncLock)
{
if (port == null)
{
}
}
}
return port;
}
}
}Then, you simply inject this instance into your reader and writer classes and let it take care of itself.
This space for rent
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thanks but I am slightly beginner with .NET and I'd rather stick with my approach.
You can have a look I slightly updated question, if you have opinion - whether my scenario is OK now I'd appreciate. (I added open and close calls)
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I thought about posting this question in the "Article Writing" forum, but decided it would get more "exposure" here, even if I risk this being seen as slightly off-topic for this forum.
The reason I ask is that I am thinking of doing an article for CodeProject that will demonstrate what explicit use of 'ApplicationContext can enable in terms of multiple window management, over-all application structure, and, more specifically, the all-too-common task of "communication" (passing data, raising/receiving event notifications, etc.) between Forms.
I've been using 'ApplicationContext (which is, as I think you know, being automatically instantiated/used "under-the-hood" of any default new Win Forms project) explicitly for years; couldn't live without it. But, I'm unclear as to how often this is used by other programmers.
And, is it, possibly, the case that at this late date in the life-time of Win Forms, such a topic has a small possible "audience" ?
thanks, Bill
«In art as in science there is no delight without the detail ... Let me repeat that unless these are thoroughly understood and remembered, all “general ideas” (so easily acquired, so profitably resold) must necessarily remain but worn passports allowing their bearers short cuts from one area of ignorance to another.» Vladimir Nabokov, commentary on translation of “Eugene Onegin.”
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BillWoodruff wrote: And, is it, possibly, the case that at this late date in the life-time of Win Forms, such a topic has a small possible "audience" ?
Likely. Definitely smaller than the all the rage web technologies. But as I'm doing mainly WinForms as well I would be interested in reading it!
cheers, Sascha
If the brain were so simple we could understand it, we would be so simple we couldn't. — Lyall Watson
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Thanks, Sascha, if a "bulb as bright" as you are still working in WinForms, that encourages me to write the article.
cheers, Bill
«In art as in science there is no delight without the detail ... Let me repeat that unless these are thoroughly understood and remembered, all “general ideas” (so easily acquired, so profitably resold) must necessarily remain but worn passports allowing their bearers short cuts from one area of ignorance to another.» Vladimir Nabokov, commentary on translation of “Eugene Onegin.”
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BillWoodruff wrote: a "bulb as bright" as you
Not sure how far this is justified but I'll take it and run 
If the brain were so simple we could understand it, we would be so simple we couldn't. — Lyall Watson
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In the excel sheet, I have more than 1 lac rows. Am trying to update specific cell and row. It's working and does the update only up to certain row but when I try A106880 row it's saying ' Make sure the object exists and that you spell its name and the path name correctly.'
string sConnection = string.Format(@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties=""Excel 12.0 Xml;HDR=No;IMEX=1""", path);
OleDbConnection _Connection = new OleDbConnection(sConnection);
_Connection.Open();
string cmd = string.Format("Update [{0}$A106880:A106880] set F1 = 12", sheetname);
System.Data.OleDb.OleDbCommand myCommand = new System.Data.OleDb.OleDbCommand(cmd, connection);
if (myCommand != null) myCommand.ExecuteNonQuery();
_Connection.Close();
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Please don't post your question in multiple forums. Choose one and stick to it.
Also posted in Q&A: Oledb excel update is not working[^]
If the brain were so simple we could understand it, we would be so simple we couldn't. — Lyall Watson
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By mistake I didn't that. Do you have answer on this?
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example (note: label1 and label2 can have only numbers):
If is label1.Text = 5 and label2.Text = 6
how to make a comparison, something like:
if (label1.Text < label2.Text)
{
MessageBox.Show("some text...",
this.Text, MessageBoxButtons.OK, MessageBoxIcon.Information);
return;
}
Please help. Thanks.
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If you are trying to compare numeric values, then parse the strings into an appropriate number format first:
int l1, l2;
if (!(int.TryParse(label1.Text, out l1) && int.TryParse(label2.Text, out l2)))
{
return;
}
if (l1 < l2)
{
...
}If you don't, then string comparisons get a bit weird-seeming, because they base the entire comparison on the first different character pair then encounter in the two strings.
So the sort order isn't what you expect:
"1", "2", "3", ... "9", "10", "11", ... Instead it orders them as
"1", "10", "11", "12", ... "2", "20", "21", ...
Otherwise, just use the String.Compare Method (String, String, StringComparison) (System)[^] to return an integer indicating the result: 0 for "same", -1 for "first is less than second", 1 for "first is greater than second".
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Thanks a lot, doing great. Problem solved.
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You need to convert both strings to numbers first. The following simple test demonstrates that the string "82" is considered less than "9".
string s1 = "82";
string s2 = "9";
int foo = s1.CompareTo(s2);
Console.WriteLine("foo is {0}", foo);
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Hi!
can we update dataset tableadapter without changing from database?
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Uhhhh what? That made no sense at all. What object are you trying to update? The database, the tableupdater, a dataset, ... what? And it what way are you trying to update it?
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of course by turning the read only false
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You're still not making any sense at all.
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how would i go about converting this following code to c# my friend sent it to me but its in c++ and i have no idea what to do with it as i code in c# code
namespace Goat
{
struct IBaseWeapon
{
virtual ~IBaseWeapon() {}
virtual string GetName(void) = 0;
virtual bool AddToCsv(string& strOut) = 0;
};
class Kap40 : public IBaseWeapon
{
public:
Kap40() = default;
virtual string GetName(void)
{
return "kap40";
}
virtual bool AddToCsv(string& strOut)
{
strOut += "xmodel, kap40_viewmodel\n";
strOut += "xmodel, kap40_worldmodel\n";
return true;
}
};
class Ak47 : public IBaseWeapon
{
public:
Ak47() = default;
virtual string GetName(void)
{
return "ak47";
}
virtual bool AddToCsv(string& strOut)
{
strOut += "xmodel, ak47_viewmodel\n";
strOut += "xmodel, ak47_worldmodel\n";
return true;
}
};
class WeaponsMng
{
public:
WeaponsMng() = default;
void AddWeapon(IBaseWeapon* pWeapon)
{
weapons_.push_back(pWeapon);
}
void RemoveWeapon(const string& name)
{
for(auto w : weapons_)
{
const string& curName = w->GetName();
if(curName == name) {
weapons_.remove(w);
}
}
}
string CreateCsc(void)
{
string res;
for(auto w : weapons_)
{
w->AddToCsv(res);
}
return res;
}
private:
std::vector<IBaseWeapon*> weapons_;
};
WeaponsMng mng;
void OnAddKap40_checkbox(bool isChecked)
{
if(isChecked)
mng.AddWeapon(new Kap40());
else
mng.RemoveWeapon("kap40");
}
void OnAddAk47_checkbox(bool isChecked)
{
if(isChecked)
mng.AddWeapon(new ak47());
else
mng.RemoveWeapon("ak47");
}
}
thank you in advance
elfenliedtopfan5.
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Understand exactly what this code is doing and rewrite in C#. You're friend sent it to you so he must have written it correct? He can explain it to you too. Nobody is going to convert it for you.
It would seem there is a ton more going on in the rest of the code that this code interacts with, so a line-by-line conversion is probably not going to do anything for you.
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You can try using the free C++ to C# converter here: [^], but I think the "translation" will only be useful to give you ideas about what the C++ code is doing, and how specific syntaxes map from C++ to C#. And, the output is likely to need considerable "massage."
Until you understand the purpose and usage of the code, you are dancing in the dark.
What I can say about the structure of the code, speaking as a "C/C++ non-native speaker", from a quick glance: ... of course you'll have a NameSpace ....
a. you have an Interface 'IBaseWeapon ... the on-line converter would convert that to an abstract class.
b. you will have (not static) classes, WeaponsMng, Ak47, Kap40
b.1. Ak47 and Kap40 will inherit from 'IBaseWeapon
b.2. WeaponsMng keeps a List of IBaseWeapon
c. you will have some static methods which should be put in a static class
«In art as in science there is no delight without the detail ... Let me repeat that unless these are thoroughly understood and remembered, all “general ideas” (so easily acquired, so profitably resold) must necessarily remain but worn passports allowing their bearers short cuts from one area of ignorance to another.» Vladimir Nabokov, commentary on translation of “Eugene Onegin.”
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I don't think it is productive to use a converter in this case because
C# classes are managed classes while the given C++ class is a native one.
For a Managed C++ (or formally, C++/CLI) class, we should write ref class instead of class - and objects are instantiated in this way:
Object^ obj1 = gcnew Object(); Object^ obj2 = ref new Object();
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Did your friend tell you what the code is supposed to do?
I can tell you it doesn't really "do" much of anything; the "intent" seems to be to provide functionality that will add / remove a weapon from your inventory; but by itself, the code cannot even do that unless it is properly integrated with the "main application" (whatever that may be).
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