sending a list from one indicator to another

[blarouche]

Hi all,


I have a question concerning the exchange of data between two indicators.

I have an indicator that have a list of price levels that I would like to use to draw in another chart with another indicator.

In my first indicator ( the one that owns the list of double) I have exposed the list like that :

[Browsable(false)]
[XmlIgnore()]
public List<double> Zone
{
get { Update(); return zone; }
}

In my second indicator ( the one that receives the list and use it to draw lines and rectangles I have the following structure :

First in my Variables region I have created a list :

#region Variables
List<double> zone = new List<double>();
#endregion

Second in my OnBarUpdate() method I initialize my list to the list of my first indicator and draw some stuff :

protected override void OnBarUpdate()
{

int count = 0;
double temp = 0;

if(Bars.FirstBarOfSession){
zone = MyfirstIndicator().Zone;
}

foreach(double item in zone){
count +=1;

if(count % 2 != 0)
temp = item;
else
DrawRectangle("Zone"+item, false, Bars.BarsSinceSession, temp, 0, item, Color.Bisque, Color.Bisque, 3);

}


I get the following error :

Error on calling 'OnBarUpdate' method on bar1 : Object reference not set to an instance of an object.


What is wrong with my code ?



Thanks


Bernard

[NinjaTrader_JoshP]

Suggest you use try-catch blocks to isolate out which line is causing you problems.

[eDanny]

Bernard, as an alternate way of doing this and using just one indicator, have you considered stream writer? On start up all charts would read from the file. If new data was then entered into parameter settings, it would be written to the file. An F5 refresh of other charts would cause a new read from the file. This would work well if setting up zones once a day but your application may be different.

[blarouche]

Thanks guys


I will try try catch block to isolate the error.

eDanny thanks for the suggestion but this indicator could go to potential clients and I would like to avoid having them pressing F5 key or any others keys to update the indicator. When you deal with the public the simpler it is the better it is...


Thanks

Bernard

[Ralph]

Bernard, you need to instantiate your list in the first indicator. It is not necessary in the second indicator because you use the reference to the first indicator-list only, your instantiation here is just trashed.

Regards
Ralph

[blarouche]

I tried a lot of things and the error starts when I initialize my list.

Ralph I am not sure I know how to code what you are explaining. Could you be more specific.

I have no problem using exposed variables or lists from an indicator to a strategy but my problem lies with the relation between two indicators...



Bernard

[Ralph]

My explanation was related to your code example in conjunction with the error message about usage of a non-initialised reference.
You use in your second indicator MyfirstIndicator().Zone, but I don't see the initialisation of property Zone in the first indicator. If you missed it, it would cause the error message mentioned.

Regards
Ralph

[blarouche]

OK I understand


I am not showing it but my list has been obviously initialized in the first indicator.



Thks



Bernard