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I'm a newbie. Please, take it easy on me if my question is too low of a level.
I've got this C-code that works fine. I want to bring it into MFC and I decided to enclose most of the functions inside a class. There are functions that take in as arguments pointers to other functions, and I have no problems understanding how it works in C although I am not the savvy programmer.
When I try to use those functions inside the class I gett errors.
For example, I have one function (called "danger") which I put inside the class and what it does it simply takes in a double and returns a "corrected" double. Then I have another member function in the same class that takes in as the first argument the pointer to the member function mentioned above (that is to "danger"). So, the first argument for the latter function is a *double.
When i compile the compiler (.NET Visual C++) tells me that it cannot convert a double (which is basically what "danger" returns) to a (__cdecl*)(double). I sort of see why the compiler tells me that, but I wonder how do I "fool" the compiler to see that it is a pointer to a function and not just a variable of type double.
please help me. I've looked through all the threads on pointers to member functions and I could not quite figure it out. Most of the threads talk about how to use the pointers to member functions when passing them as arguments to non-member functions. Or else, I am not that savvy yet.
Thanks beforehand.
Dig
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Hi to everybody,
I've been asked to assist with designs for a large enterprise scale accounting project. So far I have decided upon a n-tier design with remotable objects and webservices at the server end. I'd like to gauge the responses from everybody as to when you believe the middle and even UI layers should be split up into their own assemblies.
I am aware of the performance penalties associated with reflection vs. native object calls, but am also firmly believe that a large scale application will sooner or later use reflection in some way, shape or form. Based on this, my initial thoughts are to split the application into logical functional units.
So following these lines of thought (and these are rough thoughts), an assembly for business objects (BO), interfaces (I), data components (DC) and user interface (UI). Each of the BO, I, DC and UI will then be replicated for each logical unit: ie. debtors, creditors, stock, general ledger, system, etc.
I'd love to hear your thoughts on this and any suggestions and/or recommendations you've got.
Thanks in advance.
Edward Steward
edwardsteward@optusnet.com.au
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Edward Steward wrote: I have decided upon a n-tier design
What a lot of people don't realise is that all designs are n-tier. I presume you mean n-tier where n >= 3
Edward Steward wrote: when you believe the middle and even UI layers should be split up into their own assemblies
Yes, they should. Unless it is for a very small application. You've already mentioned this is an enterprise application so they should be separated out.
Edward Steward wrote: Based on this, my initial thoughts are to split the application into logical functional units.
"logical functional units" is a very overloaded term. No two people seem to use it the same way. What do you mean by that?
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Colin,
> I presume you mean n-tier where n >= 3
Yes this is true.
> "logical functional units" is a very overloaded term. No two people seem to use it the same way. What do you mean by that?
By "logical functional units" I refer to debtors, creditors, stock, general ledger, system, etc.
> Will you really have only one UI to allow the user to interface with the enterprise application
No this will be accessible from a variety of platforms
> Don't force them into starting one UI for half their task and then switch to another UI in order for them to complete it
No intention of it.
As you can probably see from the above points you have raised my thoughts aren't altogether clear on the topic, so I think it best to elaborate on some of the finer points of the "current design".
· Main application (EXE). Minimal code and almost a "stub" making reference to various UI assemblies.
· A common UI assembly to be used as a control library as well as base forms
· A common interface assembly handling some of the typical/common CRUD operations
· A common BO assembly for common validation code, error checking, "business base" objects, etc.
· A dedicated DAL assembly which all DC assemblies can hook to. The chosen DAL model I have used previously on a smaller project with much success. This has plenty of support for ALL sql db operations.
· A business rules assembly to be used for custom attributes. Again have used something very similar before with much success.
· Debtors - DC, I, BO, UI
· Creditors - DC, I, BO, UI
· Stock - etc, etc.
I hope this paints a clearer picture for you and I do appreciate your input.
Thanks
Edward Steward
edwardsteward@optusnet.com.au
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Edward Steward wrote: A common UI assembly to be used as a control library as well as base forms
You might want to split that out further based on platform (e.g. win forms assembly and webforms assembly). You might also want to separate the controls out - I find that useful as it puts up an additional barrier to stop me accidentally creating circular references between forms and controls. Forms should know about their controls. Controls should know nothing about the form. Separating the controls into their own assembly means that if you find yourself needing to reference the assembly with the forms then you know you've got part of the design wrong.
Edward Steward wrote: DC assemblies
Sorry, I don't see a definition for "DC". Data Controller/Connector?
Edward Steward wrote: The chosen DAL model I have used previously on a smaller project with much success. This has plenty of support for ALL sql db operations.
Fair enough - but be careful about scalability. It might scale well, or you might need to alter the design to allow it to scale well.
Edward Steward wrote: · Debtors - DC, I, BO, UI
· Creditors - DC, I, BO, UI
· Stock - etc, etc.
This can work well, but if you have circular dependencies it can start to become difficult to maintain. e.g. What happens if you have an entity that is both a Creditor and Debtor?
The only thing I'm not so sure about is the fact that you have all those pillars with the UI sitting on top of each - Are they just controls? I would imaging that the UI (the forms) would make a roof to fit on top of the pillars.
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Colin,
> Common UI
Point taken
> "DC". Data Controller/Connector
Data components
> DAL
Noted.
> Circular references
My thoughts on this is to try and loosely reference varying projects/assemblies as required by using [Assembly].Load instead of "hard" referencing the projects at design time.
> UI as roof
Yes the UI for the pillars would consist of a series of forms that are specific to the type of pillar - debtors, creditors, etc.
Edward
Edward Steward
edwardsteward@optusnet.com.au
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Edward Steward wrote: My thoughts on this is to try and loosely reference varying projects/assemblies as required by using [Assembly].Load instead of "hard" referencing the projects at design time.
As you noted earlier, there are performance hits against using reflection here. If you want your application to scale efficiently, then you have to be very careful how and when you use Assembly.Load.
Deja View - the feeling that you've seen this post before.
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Oops... I hit post instead of "Quote Selected Text"
Edward Steward wrote: an assembly for business objects (BO), interfaces (I), data components (DC) and user interface (UI).
Or even multiple assemblies for each part. For exampe. Will you really have only one UI to allow the user to interface with the enterprise application? Or will they access it via a web application, or windows application or mobile application depending on the scenario?
Edward Steward wrote: Each of the BO, I, DC and UI will then be replicated for each logical unit: ie. debtors, creditors, stock, general ledger, system, etc.
Is that really the best way? When thinking about the UI you should be thinking along the lines of what tasks the user has to complete. What is the goal of the users? Don't force them into starting one UI for half their task and then switch to another UI in order for them to complete it.
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hi...
my query is ...
i have GPS data of one track map and now
i want to display that data on google earth track map..is it possible using vb.net
thanks & regards
-- modified at 0:44 Saturday 31st March, 2007
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Don't know much about bringing in the data into Google earth but you should look at KML. Also, you might want to actually google it... a place to start would be here:
http://earth.google.com/userguide/v4/ug_gps.html[^].
_____________________________________________________________________
Our developers never release
code. Rather, it tends to escape, pillaging the countryside all around.
The Enlightenment Project (paraphrased comment)
Visit Me at GISDevCafe
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hi..
by using openfiledialog box how u can open a particular file in vb.net
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Type this code in a button:
OpenFileDialog1.Filter = "Applications(*.exe)|*.EXE|Text files (*.TXT)|*.TXT|word documents (*.doc)|*.doc |Windows Write (*.wri)|*.wri| Rich text format (*.rtf)|*.rtf| All files (*.*)|*.*" '//example filter<br />
OpenFileDialog1.ShowDialog()<br />
System.Diagnostics.Process.Start(OpenFileDialog1.FileName)<br />
Hope this helps 
My blog:[^]
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hi..
my query is ...
when i want to move my mouse position the co-ordinates of that particular position must display..
the file i am using is .bmp file
so please reply quickly
thanks & regards
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Here is what you need:
1.A timer
2.A Label (Called label3 in the example)
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
Label3.Text = Cursor.Position.X.ToString & "," & Cursor.Position.Y.ToString
End Sub
Hope this helps
My blog:[^]
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Simple question: is it possible to do this ? and how ?
OleDBConnection string in the SystemsTableAdapter.Connection is like:
"Provider=Microsoft.Jet.OLEDB.4.0;DataSource=|DataDirectory|\db\database.mdb;Persist Security Info=True"
Can i provide a stream from an embedded ressource like this to the OleDBConnection
Assembly.GetManifestResourceStream("bla.db.database.mdb")
Thanks.
-- modified at 5:54 Thursday 29th March, 2007
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I am using a Symbol device and my application pre-requisites include installing the symbol.all.arm.cab on the device.
The first time I installed the pre-requisites and the application on the device, the application ran properly without any crash.
But later, when I tried to start the application again, there was an error seen and the application did not start.
The following error was seen
TypeLoadException
Could not load type
Symbol.Generic.Reader from assembly Symbol,
Version=1.0.5000.3, Culture=neutral, PublicKeyToken=68EC8DB391F150CA.
MSDN says “TypeLoadException is thrown when the common language runtime cannot find the assembly, the type within the assembly, or cannot load the type.”
I tried reinstalling the ‘symbol.all.arm.cab’ file again, but it gives the same error.
can anyone help me in understanding why am I getting this error and what should I do to correct it.
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Please don't cross post. Pick an appropriate forum and ask the question there.
Deja View - the feeling that you've seen this post before.
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Hi
When I type netstat -a in command, it shows a specific (tcp)port is still "listening" even though the program that was using that port was shutdown. So it wasn't closed properly. I just want to know how I can close that specific port in C# .NET. Because when my program starts again, it says that port is busy.
Thanks for any help
~Jacky
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Hi all,
I have an asp.net webform which is exporting a crystal report in to Excel format. But what I need is, I would like to format the excel cells so that it should adjust the cell size or wrap the cell according to the data given in it by using VB.Net. If anybody know it pls. advice me or give me some code snippet if possible. Thank you.
Regards,
S/W Engineer
Akebono Soft Technologies
aleem_abdul@akebonosoft.com.
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Please stop cross posting. You've asked enough questions on the boards before to know the form. Pick the most appropriate forum, post your question and then wait for somebody to get the time to take a look at it.
Deja View - the feeling that you've seen this post before.
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But I need it very urgently pete. Sorry for troubling u all. But pls. try to help if possible. Thank you.
Regards,
S/W Engineer
Akebono Soft Technologies
aleem_abdul@akebonosoft.com.
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I have been trying to use timers in VS 2005. I was under the impression when the tick event fired it was similar to a hardware interrupt . Time has shown I am incorrect, I am now using a separate thread.
My question is: what is happening when the tick event fires, is it sitting in a queue waiting for a break in the thread, is it lost if the thread is busy else where, or something else?
Thanks
Jim
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That depends on which Timer is being used. There's 3 in the .NET Framework.
The System.Threading.Timer is a uses a callback delegate, which is executed on a Thread from the ThreadPool.
System.Timers.Timer is a server-based timer designed to work from worker threads in a multithreaded environment.
System.Windows.Forms.Timer is a event-based timer designed to work in a single threaded environment on the thread with your application message pump and relies on the O/S timer support.
The Timers.Timer and Forms.Timer both use events to signal the elaspe of the timer. The events are queued and must wait for the thread handling the events to get around to them.
The Threading.Timer uses a direct call to the code handling the elaspe of the timer. It doesn't have to wait for a thread to handle a queued event, but instead creates a new thread out of the ThreadPool and executes the method on that. The only thing that would slow that process down is if the ThreadPool doesn't have a thread immediately available to execute the request.
Dave Kreskowiak
Microsoft MVP - Visual Basic
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Thank you for the good explanation.
Jim
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I have made small testing app. Iniatialy I have used database connection via IDE (Data Sources -> Add New Data Source), later I have shifted my project to another PC so I had to change Data source.
I have removed old data source from IDE, attached database to another server and stored connectiong string in App.config file.
BUT when I tried to reach this information first time I found out there were more than one conn string!
Old one (which was never in App.config!) and new one.
My confusion was even greater because I haven't had .config file (nor -.settings) prior the change of data source.
Where is old connection string stored? It's not in App.config!
I made ad hoc solution for the moment, method shown passes first usable connection string:
<br />
public static bool ProvjeriKonekciju()<br />
{<br />
bool povrat = false;<br />
SqlConnection conn = null;<br />
Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);<br />
ConnectionStringsSection section = config.ConnectionStrings;<br />
ConnectionStringSettings settings;<br />
<br />
for (int i = 0; i < section.ConnectionStrings.Count; i++)<br />
{<br />
settings = section.ConnectionStrings[i];<br />
if (settings == null) continue;<br />
<br />
conn = new SqlConnection(settings.ConnectionString);<br />
try<br />
{<br />
conn.Open();<br />
if (conn.State == ConnectionState.Open)<br />
{<br />
povrat = true;<br />
_ConnString = settings.ConnectionString;<br />
povrat = true;<br />
break;<br />
}<br />
}<br />
catch (SqlException sqlex)<br />
{<br />
Debug.WriteLine(sqlex.ToString());<br />
}<br />
catch (Exception ex)<br />
{<br />
Debug.WriteLine(ex.ToString());<br />
}finally<br />
{<br />
conn.Dispose();<br />
}<br />
}<br />
return povrat;<br />
}
How can I eliminate the intruder?
I'm using Visaul C# 2005 Express.
Help.
I'm not native English speaker, so excuse me.
Feel free to point out bad code aswell.
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