I have this project where the software communicates with a remote hardware.
Based on the visible rows, I need to read only the visible section inside a buffer in the hardware and update the grid accordingly (this is to prevent reading load of irrelevant data which is currently not visible to the user).
There is no easy way of telling what are the visible rows in the GridView (I have read that there was, but now we have to dig in).

I have tried using the method in the example that was given here:
http://www.telerik.com/community/forums/wpf/gridview/firstvisiblechildindex.aspx

However, for some reason in my project it will never find the last row, therefore causing an exception.

I have used a different method of getting all the rows from the virtualizing stack panel and then iterating them to see what is the lowest item index and using the rows count at the num of rows:




This does work (although it seems to return a little more rows than expected when the scrollviewer is visible....


Still, when the UI starts I try getting the visible rows on several occasions:
radGridView_Loaded
radGridView_DataLoaded
and also: radGridView_ScrollChanged

The problem is that it is not enough...
When I get the DataLoaded event, the rowsList is still empty... I need to wait for the next LayoutUpdated event and only then call the recalculateFirstAndLastVisibleIndexes function.

If I try to rely only on the ScrollChanged event then if there are for example 10 rows and the window are can contain 20 row, then if I add or remove rows then this event is never being called.


I did not find any way to get notified when the visible rows change. Is there any solution?

Thanks.

I get the following error when trying to view the Grid demo:

The database 'C:\PROGRAM FILES (X86)\TELERIK\RADCONTROLS FOR ASP.NET AJAX Q3 2012\LIVE DEMOS\APP_DATA\NORTHWIND.MDF' cannot be opened because it is version 655. This server supports version 612 and earlier. A downgrade path is not supported.
Could not open new database 'C:\PROGRAM FILES (X86)\TELERIK\RADCONTROLS FOR ASP.NET AJAX Q3 2012\LIVE DEMOS\APP_DATA\NORTHWIND.MDF'. CREATE DATABASE is aborted.
An attempt to attach an auto-named database for file C:\Program Files (x86)\Telerik\RadControls for ASP.NET AJAX Q3 2012\Live Demos\App_Data\Northwind.mdf failed. A database with the same name exists, or specified file cannot be opened, or it is located on UNC share.

Please advise

Hi,

I want to use the Telerik grid to show a read only live feed of millions of records (while still supporting sorting, filtering, etc.).
Is it supported (I will also want to use the DataFilter to filter the live feed)? 

I have two questions:
1. I went over the documentation and couldn't find any performance guidance on how to populate the grid with millions of records of live data.
Should I feed the grid one row at a time by adding it to the Items collection? 
Should I use ObservableCollection and add rows to it when they are available?
Should I add single rows or should I add batches of rows?
If I'm using an ObservableCollection, I can't add records to it from a worker thread. I need to use the Dispatcher to actually feed the collection, which seems to slow down everything... What is the right way to do so?
I tried implementing the ObservableCollection approach, adding 3000 rows every second (while using the Dispacher and DeferRefresh), but it is a bit slow and not so responsive. 

2. When implementing the ObservableCollection and the Dispatcher, I noticed a strange scrolling issue. Every time there is an update (adding rows to the collection) the grid scrolls back to the first row.
I actually want a different behavior and I can't figure out how to do that.
I want the grid to automatically scroll to the last row, but if the user is manually scrolling, I want the automatic scrolling to stop and the grid to stay where the user scrolled to.
I can probably implement the auto scrolling myself, but I can't find how to tell the grid not to scroll to the first line. How can I do that?

Thank you,
Yoav.

How can I implement blur in MainWindow when I opened ModalWindow?
See attached file. Tnank You.

Hello, I have got Window with modalWindow.
I face issue.
When I am opening the modal window and after clicking on iconApp on taskbar, modal window is disappears and I can't do anything with my app (only end app in task manager). See attached files

 

I created the mainWindow by this way.
in CS code I call method as


I created a modal window in exactly the same way.

and call following method

I'm doing something wrong or this is a bug?
Thank you.


I use the following code to show the icon in the system tray (taskbar).
Is there any best way?

I am binding a RadSparkline against an INotifyCollectionChanged object. This object is NOT an ObservableCollection<>. It is raising CollectionChanged, with Action: Add, with StartingIndex as -1. This should be allowed when the collection is unordered, as mine is. However, RadSparkline is throwing an exception:

ArgumentOutOfRangeException Index must be within the bounds of the List.
   at System.ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument argument, ExceptionResource resource)
   at System.Collections.Generic.List`1.Insert(Int32 index, T item)
   at Telerik.Windows.Controls.ProjectedView`1.ObservableSourceListCollectionChanged(Object sender, NotifyCollectionChangedEventArgs e) in c:\TB\105\WPF_Scrum\Release_WPF\Sources\Development\Controls\DataVisualization\Common\DataProjection\ProjectedView.cs:line 179

I am going to solve this problem by making a temporary ObservableCollection, and adding new items to the end of it as they arrive. However, this should not be required.

Hi
I would like to use a single property grid to present a class that is selectable by a user. Also, I want to control what properties are presented for each class. To be more specific, I have currently five tables in SQL Server that are mapped using OpenAccessORM. In the future the number of tables may increase so I would only want to update the entity model component. I want the user to be able to select which table they want to view in the propertygrid and I also want to limit the columns of each table that are presented in the propertygrid.

With regards to the subset of properties, is there a way to use AutogeneratePropertyDefinitions="True" for a subset of columns? If not, would I have to add the property definitions I want to present in code rather than XAML?

To be able to use a single property grid, would I need to use DynamicObject?

I'm using RadControls Q3 (2012.03.1017) and OpenaccessORM Q3 (2012.03.1012).

Regards
Craig

Dear Telerik Team!

I use custom appointment which inherits from EntityObject. What I want to achieve is to place a button on an appointment, so I placed following code on the custom appointment template:

I'm able to click the button and execute its command, but when I change "Approved" property the UI is not updating. When I try to bind the content of the button to some other property, like "Subject" it is working fine. The problem is with custom properties, the ones which are not part of original appointment class. Could you please suggest some solution for that problem? I'd be very grateful.

Many thanks and best regards
Krzysztof Kaźmierczak

Hi,

I'm using Telerik RadControls Q3 2012. After the update, I plan to add a Bollinger Band to a ChartView. However, after several trials, it always hangs the application by System.NullReferenceException: Object reference not set to an instance of an object.

The ChartView I'm using is a simple LineSeries chart in XAML:

This is how I add the Bollinger Band to the chart:

 

 

 

 

And this is the StackTrace for the Exception caught:
  

Any help will be welcome.
Many thanks!

Frankie

Hi!

I've tried to add a custom function to the functions list and haven'd found any way to do it. In Win Forms, this is possible by extending

Telerik.Data.Expressions.ExpressionContext

class. However, in WPF i haven't found any similar class.
Can you help, please?
Alex