|
I have a background worker that executes a long running database extraction. Just recently, i have been asked to add a feature to cancel the operation. My issue with this is that the extraction is not done in a single query. My worker executes a query then waits a specified amount of time (30 seconds to 24 hours) and then executes a second query. The first query extracts data from the (current time - a user specified length of time) to current time and writes it to a file. the second query extracts data from the current time to the (current time + a user specified length of time) and writes it to a file. the wait in the middle is the accomplished with an AutoResetEvent and timespan. The below shows some pseudo code for the DoWork and RunWorkerCompleted events
DoWork
...update a status data table that the process has started
...execute query from this point in time and up to 24 hours earlier
...wait(time span, false)
...execute second query
RunWorkerCompleted
if e.Error
status = "Failed
if e.Cancelled
status - "Stopped By User"
else:status - "Completed"
....update the status data table that the process has completed
How do I go about cancelling this background worker. I have tried cancelAsync but because the process could be in the waitone section, I wouldnt be able to check the cancellation pending property until after the wait has finished, which could be hours. Is there a way to cancel a reset event?
Thanks for any advice
|
|
|
|
|
Instead of doing one big wait operation, put it in a loop...
timeout = DateTime.Now.Add(timespan)
Do While DateTime.Now < timeout AndAlso Not e.Cancelled
Loop
If e.Cancelled Then
.....
|
|
|
|
|
Hi Ian,
thanks for responding... i didnt even think of a loop (probably because its too simple). One other question then if you dont mind, because my background worker does its tasks in a few steps, should I check the cancellation pending before doing each one
check cancellation
do first query
do wait ...while checking cancellation
check cancellation
do second query
|
|
|
|
|
Generally, yes, but it depends on what you're doing, and on how long you expect each operation to take. It's a matter of balancing it between extra code/complexity and more responsiveness.
|
|
|
|
|
The data extraction will be the most costly time wise but even then I dont expect them to take an extraordinarily long time. I guess i will have to do some testing and see the best options. Thanks again for the advice
|
|
|
|
|
|
Hi,
I have a strange issue which I can't seem to find an answer to. I'm using VB.net 2003. I've created a form which containes textboxes. When entering data into a textbox, it is being displayed in reverse. This seems to happen when I place the cursor at the begining of data that is already in the textbox or when I start typing into a NULL textbox.
I have other forms which work just fine. This one was working great until this morning. I'm sure that I can't be the first person to run into this issue but I can't seem to find an answer anywhere.
Thanks in advance,
Nick
|
|
|
|
|
When your cursor is at the beginning of the text box, are you clicking the mouse button to reset the cursor to the beginning of the text box?
You do know clicking your mouse in a text box will move the cursor.. right?
|
|
|
|
|
Hi,
May be that the "Home" key of your keyboard have drinked some drop of coffee or whisky?
modified on Tuesday, September 15, 2009 2:01 PM
|
|
|
|
|
OK...thanks for the NON-answers.
"You do know clicking your mouse in a text box will move the cursor.. right?"
"May be that your "Home" key on the keyboard have drinked some drop of coffee or whisky?"
Lovely responses...NOT!
I figured it out. I was using the "TextChanged" property when I should have been using the "Leave" property. "TextChanged" kept placing the cursor at the begining of the field on every keystroke.
|
|
|
|
|
I am not exactly sure why you are jumping on everyone else, and using that kind of attitude. You provided no code, and a pretty weak explanation of the problem.
It is a little hard to give a sound response when you don't supply the correct information. Next time you post, try to help everyone out a little bit, and supply some real information. Otherwise, you will get answers that don't help.
|
|
|
|
|
I'm not jumping on anyone else and I could have lived with answers that didn't help. At least they would have been answers.
If I knew which part of the code was causing the issue, I would have included it. At the very least, that's the answer that I should have received. Silence would have been far more intelligent than the smart ass remarks that I did receive.
|
|
|
|
|
Nick Leporacci wrote: "TextChanged" kept placing the cursor at the begining of the field on every keystroke.
No, it did not. Your code moved it. The event does nothing.
You jumped on every one here for making wise ass comments, but the fact is, if you have a control doing something weird, you should start by looking at any code that involves that control, especially events. Just commenting out your code would have told you which part had the issue, by a method of elimination. When people post questions with no code at all, the most you can hope for is guesses, and those guesses will probably follow the same process of elimination that causes tech support to ask things like 'is the computer plugged in'.
Christian Graus
Driven to the arms of OSX by Vista.
Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
|
|
|
|
|
When answering a question please:
1.Read the question carefully
2.Understand that English isn't everyone's first language so be lenient of bad spelling and grammar
3.If a question is poorly phrased then either ask for clarification, ignore it, or mark it down. Insults are not welcome
4.If the question is inappropriate then click the 'vote to remove message' button
Insults, slap-downs and sarcasm aren't welcome. Let's work to help developers, not make them feel stupid.
------------------------------------------------------------------------
Do you remember this? The above is one reason that I joined this message board. I started coding back when assembler was the in language. Because of the above, I thought that I'd get honest and possibly thoughtful responses to my questions on VB regardless of how rediculous they may have seemed. I guess I was wrong. Obviously, you don't take much stock in what you've written. Please remove me from this site. I'd rather spend my afternoons searching Google for the answers that I need.
|
|
|
|
|
Wow - if people trying to help you blind upset you because they suggest things you've thought of, offends you so much, perhaps you should withdraw from all sorts of online communication, because you sure are a little over sensitive.
Christian Graus
Driven to the arms of OSX by Vista.
Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
|
|
|
|
|
Damn your easily insulted.
K I'll give you that the answers given weren't exactly helpful but then again you didn't give people much to go on.
Also CG's response was valid, the first thing you do when your program acts weird is find the code that makes it act weird (process of elimination). Since you'v been programming from the time off assembler you should have known this, done this and found the solution without asking here or at the very least been able to post the code that was making your program act weird.
Instead you opted for the fast way and just ask here and hope somebody somewhere had a way of reading your mind / code and solve it.
Nick Leporacci wrote: Please remove me from this site.
CG doesn't have the admin rights to this anymore so why ask him?
If you don't want to spend time here anymore then just don't log in.
|
|
|
|
|
Tom Deketelaere wrote: CG doesn't have the admin rights to this anymore so why ask him?
If you don't want to spend time here anymore then just don't log in.
I don't think there's ever been a process to 'remove' people.
Christian Graus
Driven to the arms of OSX by Vista.
Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
|
|
|
|
|
Well I know Chris has done it a couple times after the person himself asked it in the bugs/suggestion forum.
Don't ask me how tho  .
|
|
|
|
|
If your keyboard have not drinked some drop of coffee or whisky, may be that when you seen the reverse-text in your TextBox, you typed "!diputS a era uoY" and you read "You are a Stupid!" ?
If yes, this is not a iussue! At contrary, this means that not only your code is correctly working, but it is also an "Auto-learning" code!
Regards
|
|
|
|
|
Hello everyone,
Could someone point me on the right direction on this.
Objective:
Am trying to persistently populate a datagrid using XML data from a URL
Problem:
Not sure which appropriate class has the method(s) i could use to pull XML directly from the URL so i can work on it locally. The scenario is i need to populate a database with that data from the URL, and keep appending to the DB as need arises then bind my datagrid to the DB. Whether this is the most efficient method is still debateable.
If anyone has some insight or tips working with XML URI in vb.net i'd really appreciate the conversation
Peace & Many Thanks
|
|
|
|
|
You will have to break your problem down into steps first.
First a URL itself is nothing more than a location marker, a link. The URL itself does not contain any XML. Your URL is just telling you where to get the XML data. So the first step is, getting the data (any data) from the location provided by the URL.
Then you can look at the data itself. Is the data actually always XML, or does the location contain more than one file? How is the XML data structured, and is that structure always the same? Do the files have a static name (just data.xml) or dynamic (for example 2009-09-16_data.xml)? Do you need all the data from the XML file, or just parts of it?
Once you have that solved, you can start looking into putting the data you retrieved into a dataset or datatable, which you can then translate into your db.
The last step would be to create a dataset, which you populate from the db, and bind to the datagrid.
My advice is free, and you may get what you paid for.
|
|
|
|
|
Well I have at least accomplished the first step  . I was hoping to pull the entire thing from the URL provided by the webservice as XML but that proved to be a Mobius strip, so I used the web request class which returns the entire contents of the XML file, as a data stream (string. yuk I know  ). I realize this is potentially a bad move though but this is the only solution i've found so far that gets me past the first obstacle. am trying to reformat the stream now into something i can pump into a SQL database. Also just so you know the structure for the xml files are always the same, but i only need parts of the content in it as updated from time to time.
Anyway I appreciate your insight I'll post back when am past the 3rd step in your reply. This project definitely deserves to be an article and naturally you will be acknowledged
Many thanks
|
|
|
|
|
hi all,
i want to just ask whether or not save credit card info of any customer in database?
|
|
|
|
|
That would be up to your application and customer requirements, not us.
Personally, I think it's a bad idea.
|
|
|
|
|
Only if you are 100% sure its secure - both from internal and external users, encrypted, etc etc. Generally a bad idea.
Bob
Ashfield Consultants Ltd
Proud to be a 2009 Code Project MVP
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
