This is a migrated thread and some comments may be shown as answers.

How to use GridView with VirtualQueryableCollectionView for growing datasource?

6 Answers 217 Views

GridView

This is a migrated thread and some comments may be shown as answers.

6 Answers, 1 is accepted

answered on 13 Sep 2016, 03:53 AM

Stefan, thanks for your quick reply.

I have checked the linked thread you mentioned. The first question in that thread is similar as mine. However, I don't find a final solution for it in that thread.

The solution Vlad given in that thread, use a timer to add a new item to VirtualQueryableCollectionView every second seems not applicable for my case, since the database is updated by other user via another application. And I don't know when and how many rows will be added. So I wonder if there is a way to simply "refresh" the underlying data source (the db query) every second manually, and gridview will automatically fetch the new data?

answered on 18 Sep 2016, 12:22 PM

gridview-issue.png

Thanks, Stefan! I have tried using the Refresh method, but I can't make it working. As shown in the screenshot, the gridview will not show the latest data in the SQLite database. You can see there are only 9 rows in the gridview which does not match the records number in SQLite database.

My code snippet:

public partial class MainWindow : Window

{

private const string _connStringTemplate =

"metadata=res://*/IomapMonitorModel.csdl|res://*/IomapMonitorModel.ssdl|res://*/IomapMonitorModel.msl;provider=System.Data.SQLite.EF6;provider connection string='data source={0}'"

;

private const string _dbPath = "t4.iop";

private VirtualQueryableCollectionView _cv;

private IomapMonitorEntities _context;

private int _tick = 0;

public MainWindow()

{

InitializeComponent();

var _connStr = String.Format(_connStringTemplate, _dbPath);

_context = new IomapMonitorEntities(_connStr);

var query = _context.RawRecords.OrderBy(o => o.Id);

_cv = new VirtualQueryableCollectionView(query) { LoadSize = 100 };

DataContext = _cv;

StartRefresh();

}

private void StartRefresh()

{

var timer = new Timer(1000);

timer.Elapsed += new ElapsedEventHandler((obj, e) =>

{

if (_cv != null)

{

if (_tick < 20)

{

_context.RawRecords.Add(new RawRecord()

{

CardId = 0,

CardType = "422",

ChannelId = 0,

Direction = "RX",

ProtocolType = "422",

Tick = _tick++,

TimeStamp = 11111,

Data = new byte[] { 9, 8, 7 },

Miscellaneous = null

});

_context.SaveChanges();

}

_cv.Refresh();

}

});

timer.AutoReset = true;

timer.Enabled = true;

}