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or just do
DataRow dRow = ds.Tables[0].NewRow();
i.e. refer to the table as you did a few lines earlier.
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Thanks, your suggestion is the right way to refer to the table instead of giving it a name as I did.
Thanks much it works great now.
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Actually, I'm not sure about that. Giving the table a name means that the lookup will always be the same, even if you change the access to load some other query into ds first. I'd do
da.Fill(ds,"testtbl");
DataTable testtbl = da.Tables["testtbl"];
DataRow dr = testtbl.NewRow();
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I wonder if anyone could help me on adding picture in text box
Sincerely Yours
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This question was already posted in Q&A[^]; please post in one location only.
0100000101101110011001000111001011101001
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You should be stick at one place don't try to Cross post. you can use "Have a question or Comment at bottom of answer" to revert back answerer.
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please do not repost
***** Programme comme si dept soutien technique. est plein de tueurs en série et ils savent adresse de votre domicile. *****
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Hi,
I am looking for some recommendations about an application model I need to generate.
This application will be used by multi-users in multiple locations.
I have Database and I need to display around 20 to 30K records in front end application and also wants to show Live Data as well modified data from database.
What are different technologies I can utilize in DotNet FrameWork?
This is what I came across from my thoughts:
Backend Data Source: Database
For logic and data extraction : WCF
Front End App: Multi-Threaded app (not sure about web based or desktop based.)
Can somebody with experience can guide me?
Regards,
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vjs2445 wrote: This application will be used by multi-users in multiple locations
vjs2445 wrote: Can somebody with experience can guide me?
People usually work on a snapshot of the data, and databases usually don't notify the app that there has been a change in the dataset. Sql Server has the Notification Services, might help.
You could keep everything in memory, using the INotifyPropertyChanged interface, and broadcast all changes to each client. Sh*t happens when two people simultaneous edit my name.
How much users, in how many locations? I don't like the idea of updating a 5Mb blob and sending the new version over the network to a 1000+ users, it might cripple the network very fast, whilst most users aren't even working/viewing that particular blob.
Bastard Programmer from Hell 
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Well before this I need to know what are the different concepts and Technologies and different level I can use to fit in this kind of app model.
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This is not a standard application model, due to aforementioned problems, and doesn't happen out-of-the-box.
It'd be wiser to create a webapplication and have it poll using Ajax to show the user the latest snapshot of the data he or she is using right now, as opposed to sending every change to every user, regardless whether they need it or not.
Bastard Programmer from Hell
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Eddy Vluggen wrote: sending every change to every user
One such app I wrote was for monitoring the activity of a dispatching system I wrote and every user did need to see all the same data. So I had a Windows Service produce an XML file that each client downloaded periodically (every ten to thirty seconds or so, configurable). But there were only around 5000 entries per day.
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Fetching data periodically is a bit different from pushing updates.
..and yes, it's possible to have a console-app that hosts a tcp server, and only send the required updates. That's usually not done for a complete database.
Bastard Programmer from Hell
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Eddy Vluggen wrote: pushing updates
Well pushing is never a good idea. Polling is the only way, whatever the implementation.
Eddy Vluggen wrote: not done for a complete database
Oh, heck no, only the pertinent information.
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PIEBALDconsult wrote: Well pushing is never a good idea. Polling is the only way, whatever the implementation.
Life isn't that black and white; we built a realtime visualization of a plant, and it worked nicely under that architecture. Then again, that too is very different from making a database update it's clients.
I'd guess that games like World of Warcraft work in a similar way
Bastard Programmer from Hell
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Pushing is sometimes exactly what you want. Only in a web app is it not an option to consider, and that's because it's impossible. In general pushing uses less bandwidth because you only push when there is a change, whereas polling makes lots of 'has anything changed? no' requests.
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I expect that push requires a bunch of "are you still there? yes" messages, so I don't see the difference. Pull also makes it easier for different clients to poll at different intervals. And also allows a button to "get updates now".
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TCP handles keep-alive on a very low level and the bandwidth usage is negligible. (Actually as recently discussed in another thread, it doesn't necessarily send any messages at all.)
Why would you need to poll at different intervals if you're receiving the data you're interested in continuously? The volume of updates is the same either way, unless your infrequently updated client actually misses out on some updates, but it is more continuous and therefore less peak-intensive if it is pushed rather than pulled.
You don't need a button to 'get updates now' if you're always up to date. Having such a button is a sign that you should be doing real live updating, i.e. push, unless it's a web app where that's impossible.
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vjs2445 wrote: display around 20 to 30K records in front end application
That's probably a bad idea. I know I would never want to see that much data at one time. What do the users want?
vjs2445 wrote: show Live Data
In the past I've used a timer (System.Timers.Timer) to poll for new data; I made the interval user-settable.
vjs2445 wrote: Multi-Threaded app
The Timer takes care of much of that.
We would need to know more about kind of data and application this is.
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Following is the req:
Trade Portfolios needs to be reconcile and if good then the end users (Say about 20-30users) will use it.
If not good then the differences need to updated in the database and should reflect the modified data to all users(kind of live data) and again the same above process.
There will be addition of new data in the database and that also needs to be displayed as Live data.
Please provide the your expertise on the above requirements:
Right now my concern is to to give a proposal How we can achieve with What different technologies?
I am recommending the
back end data source is : sybase or sql server
Front end will be either Excel or CSharp multithreaded application.
Middle portion: Should I use WFC (Web Services) or some thing else not sure?
Please provide your feedback.
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I would write an app that allows a user to get the next portfolio to reconcile, and shows only that one. Once the portfolio is marked as reconciled, the next portfolio can be retrieved.
Yes, use SQL Server.
Yes, use C# -- but it needn't be multi-threaded.
Yes, use WCF.
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Well thats good cuzz we are narrowed down to choices.
What would you recommend from
Front End: with 20 to 30K records of data: web based front end or desktop based front end. Which one makes more sense?
Middle End: WCF: Do you know any good book or valuable resources from Beginning to Advance level on this WCF?
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vjs2445 wrote: with 20 to 30K records of data
NO NO NO NO NO!!!
vjs2445 wrote: desktop based front end
That's what I do, but that's just me.
vjs2445 wrote: WCF: Do you know any good book or valuable resources
I have a copy if this[^], but you could probably get something newer. And there are articles here too (I haven't written mine yet).
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I personally use web based (using Silverlight) now even though I'd prefer to develop desktop with WPF. This opens up the app to Mac users as well. Also there's no installation/deployment issues.
WCF with Silverlight and/or WPF will give you simplified communication development including duplex communication for "pushing" data to clients. Note WCF has nothing to do with data extraction. Everything you need to know with samples can be found in the docs: Windows Communication Foundation[^]
Mark Salsbery
Microsoft MVP - Visual C++
![Java | [Coffee]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/coffee.gif)
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