Addon with MarketDepth

[cls71]

Hello.

This Add-on displays the Ask side of the DOM. Video with the Addon running:

http://screencast.com/t/t7FEgPKwC3v

It is based on SampleAddon from NinjaTrader_Jesse:

http://ninjatrader.com/support/forum/showpost.php?p=410954&postcount=8

When I create a new tab page looks like if past data remain on memory. ES 12-15 must have ten ladders, but has twenty.
This bug doesn't occurs when the addon starts, but when a new tab page is created.
(If an addon is already displayed and a new addon is created, the bug appears too.)


Snapshots from the debugging:

Here is when the addon is created for first time. marketDepth.Asks.Count = 0. Correct.





Here the following times. marketDepth.Asks.Count = 20. Incorrect.




I attach the code.

Thanks.

[NinjaTrader_Jesse]

Hello,

I am currently looking through the code to see how this could be happening. Based on the video I do see how the list was "duplicated", I am unsure if this was the underlying collection that contained more items at that time or if this is the way the DataGrid is being refreshed manually/time it is refreshed.

It appears the underlying collections are not notifying on collection changed events so this would likely be why you are using Items.Refresh(), I am unsure if that is also connected here. I will post back once I have had further time to research this.

I look forward to being of further assistance.

[NinjaTrader_Jesse]

Hello,

I looked over the code but have been unable reproduce this on my end.

I tried using a Observable collection rather than the actual collection to prevent using Refresh arbitrarily, I would like to see if you could try this approach instead and see if you still have the same outcome.

Rather than setting the ItemSource directly to the Ask collection, I had added the following code:

private ObservableCollection<MarketDepthRow> askCollection = new ObservableCollection<MarketDepthRow>();

datagridAsks.ItemsSource = askCollection;

private void marketDepth_Update(object sender, MarketDepthEventArgs e)
{
	if(e.MarketDataType == MarketDataType.Ask )
	{
              askCollection.Clear();
	      foreach (MarketDepthRow marketDepthRow in marketDepth.Asks)
	      {
                   askCollection.Add(marketDepthRow);
                }
	}
}

Rather than having to manually reload the datagrid, this would notify the grid of the changes in the collection each time it is updated. I have not had any duplication of the list using either method, this would just be another way of accomplishing the same task although this uses the standard notify approach.

I look forward to being of further assistance.

[cls71]

Yes, the outcome is correct now. The original code works well also.
Maybe the issue was only with beta5. I don't remember if I did with beta5 or beta6, sorry.

Thanks very much.