Anyone have DevExpress LinqInstantFeedbackSource working with DA Linq?

Data Abstract
1

Trying to get it to work without success so far. I’ve tried variations on the code below. It makes a whole bunch of TOP 128 calls before stopping and doesn’t display any data. Just the rows. When I scroll SQL Profiler starts registering lots of queries again with TOP 201 next, then lots of TOP 1310 calls. Works fine with a regular DataSource but I’d really, really like to get this LinqInstantFeedbackSource working. Using the EntityInstantFeedbackSource with Entity Framework is wonderful, but I need to get a mobile app up and running with a very low maintenance server. Since this is essentially a readonly data pump I don’t want to mess with WCF or WebAPI 2.0. It needs smooth scrolling/paging through potentially large inventories, though, which is why I’d like to see if I can get this working with the linq version.

void linqInstantFeedbackSource1_GetQueryable(object sender, GetQueryableEventArgs e)
{
    e.QueryableSource = fDataModule.DataAdapter.GetTable<Item>().AsQueryable<Item>();
}

TYIA,
Ron

2

Hello

Did you set the “KeyExpression” property of the LinqInstantFeedbackSource component? With this property set I see the exact expected behavior:

  1. A small chunk of data is loaded to display it immediately
  2. When a user starts to scroll down DataSource loads a set of data rows keys and then loads data needed to display using these primary key values
  3. While user scrolls down the bigger and bigger list of primary key values is loaded

I’ve successfully attached a table with over 25k of rows in it and only data needed to display were loaded.

Still I have an additional question for you - what do you mean by “Mobile Application”? I don’t see DeveloperExpress .NET controls support for mobile platforms.

Regards

3

Good to hear! I did set the KeyExpression property, but not in the GetQueryable method. I’ll try and update my version and see if that fixes what I’m seeing since I assume you’re probably testing with the latest version. If it does I should be able to afford to renew the .NET portion or my expired subscription.

Regarding mobile, I have a DevExpress Universal subscription so I have their DevExtreme suite. I’m on my own and can’t afford to develop multiple native versions. I’d prefer to, but time and money… And this is just displaying some tabular data, basic search, and some charts. Things DevExtreme performs well enough on with for current needs.

4

Please note that DevExtreme suite is a HTML5/JS framework. So I’m afraid this will require completely different approach than desktop development using C#/.NET

5

Of course it is. I think you’ve misunderstood that the whole thing will be mobile. I can see how my statement might be misunderstood that way. Both the regular .NET client and the mobile portion will use the same data service, but there’s no expectation that they’ll consume the data by the same means.

6

Ah, my bad. So I suggest you to download latest trial and try to create an app with it. Just don’t forget to set the KeyExpression property. Also

e.QueryableSource = fDataModule.DataAdapter.GetTable<Item>().AsQueryable<Item>();

is equal to

e.QueryableSource = fDataModule.DataAdapter.GetTable<Item>();

(at least in the current implementation of AsQueryable). Still it is better to use the latter notation.

For JS there is a Data Abstract for JavaScript package that probably can be used together with DevExtreme (please start separate talk thread if you’ll decide to use it).

Regards