|
|
I would like to mark a form as abstract and then inherit from that form.
My problem is that, when I open the child form. VS tells me that it's unable to open the mother form because it's abstract
any idea ?
|
|
|
|
|
You cannot instantiate an abstract class. Declaring a class as abstract is telling the compiler that you never want to instantiate it, only derive from it and instantiate the concrete derivatives.
What do you mean by "child form" and "mother form" in this context? When I think of that the parent form is opened before the child form is, so I can't think what you mean by it.
Do you want to know more?
Vogon Building and Loan advise that your planet is at risk if you do not keep up repayments on any mortgage secured upon it. Please remember that the force of gravity can go up as well as down.
|
|
|
|
|
I know that it's impossible to instantiate an abstract class. And I don't want to.
The term mother form and child form are translated from french ... i'll try to explain a little better.
I have a form (fmBase) from wich I inherit all other forms in my application.
I will never instantiate fmBase in the application, only herited forms. I could live without declaring fmBase as abstract but I would like to declare abstract method in fmBase.
If I declare fmBase as abstract, it's impossible to open the inherited forms in the VS designer. VS says it can't create an instance of fmBase. I understand that it's impossible to crate an instance of fmBase to show in the designer, but I would just like to open an inherited form.
I hope I explained better that time, I'm french and it's sometimes difficult to put the right word at the right place 
TIA
Julien
|
|
|
|
|
|
|
hi! can anyone show me how to make an expiration for a certain software where backtracking of dates (i.e. changing the system date) will not nullify the license.. also, the software will have a counter which counts how many times the software is being used.. thanks!!
|
|
|
|
|
Here what you need to check is, while generating lisence key, you need to use some other values to produce entire lisence key. Say combination of dates ,customer name and etc.
If you follow this , then you don't want to worry about date changing.
Sreejith Nair
[ My Articles ]
|
|
|
|
|
Dear All,
i have a problem with a deployment project, in the first of this project i can add a merge model to that project and i have reached to a point where i hade an error while compiling that project
unable to import merge module
if any pody know what is that error related to, i will be thankful for help
best regards
Mhmoud Rawas
------------
Software Eng.
|
|
|
|
|
i'm just learning C#, just to warn you.
I want to create a app that will be able to perform various functions on chemical equations. so if the input was "C12H4O3Mn5". how would i divide each element, some one letter, some 2 into workable variables along with their corresponding amounts which would have to be integers in seperate variables?
what would be ideal is 2 arrays, one with the element and one with the ammount correspondingly.
|
|
|
|
|
Please check the member function which is avilable in string class. All functions are self explanatory and contain nice examples.So please refer MSDN.
Sreejith Nair
[ My Articles ]
|
|
|
|
|
Anonymous wrote:
what would be ideal is 2 arrays, one with the element and one with the ammount correspondingly
I would have said the ideal would be to create a class. Having two arrays in this way can be problematic - especially if they arrays become out of sync with each other.
As for splitting the input string. I imagine that the best solution would be to use a regular expression, however I'm not to good with them.
Do you want to know more?
Vogon Building and Loan advise that your planet is at risk if you do not keep up repayments on any mortgage secured upon it. Please remember that the force of gravity can go up as well as down.
|
|
|
|
|
Hello,
My Form has a listView control, that is acting as a
message window. Messages are appended to the listView.
I would like the scrollbar knob to stay positioned at
the bottom of the vertical scrollbar. How can I do it?
Regards,
Zishan
|
|
|
|
|
This code blcok will help you to get the visibility of last item in your listview control. And if nessasary it will scroll upto the end.
<br />
if(listView1.Scrollable)<br />
listView1.Items[listView1.Items.Count-1].EnsureVisible();
Sreejith Nair
[ My Articles ]
|
|
|
|
|
Thanks a lot.. this solved my problem
Best regards,
Zishan
|
|
|
|
|
I hava simple program that posts a xml file over the web to an Apache Web Service.
HttpWebRequest wr = ()WebRequest.Create(url);
wr.ContentType = "text/xml";
wr.KeepAlive = false;
wr.Timeout = 60000;
wr.Method = "POST";
Stream s = wr.RequestStream();
.....
.....
WebResponse response = wr.GetResponse();
The TCP Timeout is occuring on the wr.RequestStream() after the 5th time file sent.
Knowingly the program sends many XML files a minute. It is quite efficient producing them. However it would appear to block after the 5th one and then everything yields a TCP timeout. I increased the timeout to 1 minute on my side but yet I get the timeout within 20 seconds.
Guillermo Jimenez
|
|
|
|
|
Are you closing your connections? The number 5 seems almost programmed, like that's a connection limit. You need to make sure that you close your connections by calling Close or, better yet, use the using block statement to make sure the HttpWebResponse gets disposed (which closes the connection among other things):
using (HttpWebResponse response =
(HttpWebResponse)request.GetResponse())
{
}The using block statement compiles to a try-finally block, where it is disposed - if not null - in the finally block (so exceptions are thrown but the finally block is always executed before execution returns to the caller).
Now, if you need to allocate N number of connections like a web crawler or something, you need to control your threads. Don't just create new threads when you feel you have to. Using the ThreadPool helps in these case.
The .NET BCL also includes checks to prevent too many stops. This uses a ServicePointManager and the ServicePoint classes to limit connections. The ServicePointManager.DefaultConnectionLimit gets or sets the default number of connections. Setting that higher may help, but most servers implement their own connection limits.
This posting is provided "AS IS" with no warranties, and confers no rights.
Software Design Engineer
Developer Division Sustained Engineering
Microsoft
[My Articles] [My Blog]
|
|
|
|
|
Heath
You are close to becoming my personal mentor. You have answered every single one of my questions with incredible accuracy. Thanks a lot.
Back to WebResponse
I also thought that forcing the connection closed from my side was the way to go and added a finally block to set the object to null. Of course your using {} block is a much more elegant solution and I happily threw mine away to use yours. I have not tested either. I will let you know.
Look out for my next question, I'm sure you have the answer!
Guillermo
|
|
|
|
|
Setting the reference to null won't close the connection (studying the IL for the module in the assembly would help alleviate these assumptions). Even assuming it was the only reference, the GC (garbage collector) will only free the memory used by the response when the GC "feels like it" (idle time or when memory is nearly exhausted, and even then it may not get freed right away; other generations may come first).
You must dispose of the object or explicitly call Close to close the connection.
This posting is provided "AS IS" with no warranties, and confers no rights.
Software Design Engineer
Developer Division Sustained Engineering
Microsoft
[My Articles] [My Blog]
|
|
|
|
|
Hello,
I am writing an interpreter program that should implement a parser class that uses a parse tree and then have the expressions evaluated into an evaluator class. The second option is to use a syntax called Grammar (which I was told can implement both the Parser and the Evaluator in it).
Any ideas to help me out? do you know of any URL or anywhere I can get a better idea (sort of tutorial from which I can learn) on how to implement one of these two?
Thank you in advance,
A Newbie in tha block
|
|
|
|
|
I've worked mostly with compilers, but they are not too far off from interpretive evaluators. 
So...
The approach I would take is dependant upon how complex the language is. If the language is along the lines of assembler:
op parm,target
-or-
macro
Then your Grammar processor is acceptable.
The more english-like or complex the structures are, then you need to implement a parser class (validate the input, identify key tokens, etc.) then once the phrase is parsed you evaluate and execute the parsed elements.
There are 10 kinds of people in the world.
Those that read binary...
...and those who don't.
|
|
|
|
|
|
Hi,
I'm trying to create an application that, given a URL, will spider/crawl through all publicly viewable directories at the URL, and list all the files the contain in a listbox or grid of some sort. Does anyone know of any tutorials which cover this sort of spidering/crawling (preferably in C#)? - I looked, but I couldn't find anything of merit. If no one knows of any tutorials, I would appreciate any push in the right direction as to what classes might be needed.
Thanks,
Justin
|
|
|
|
|
Off the top of my head I don't know of any links that discuss this, but in reality if you break the problem down into smaller pieces, it really shouldn't be that difficult. You will need a mechanism to given a URL, extract the HTML content returned from the server. You would want to look into the HttpWebRequest class to do that. Once you had the content it's simply a matter of parsing, whether or not you tokenize the document or use regular expressions, that's up to you. Hopefully this should get you started.
- Nick Parker
My Blog | My Articles
|
|
|
|
|
...and combine what Nick said with the SgmlReader[^] to read and help parse the HTML (HTML is an SGML grammar).
This posting is provided "AS IS" with no warranties, and confers no rights.
Software Design Engineer
Developer Division Sustained Engineering
Microsoft
[My Articles] [My Blog]
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
