Reference not set to an instance of an object

Desktop SDK - Indicators
1

Hello!

I have a short code as test of an indicator based on 5 minutes time frame and I want this indicator to be ploted on a tick chart.

When I plot this indicator on the chart, the plateforme freezees and I obtaine an error message: Object reference not set to an instance of an object.

Usually, the such message comes, that means there is a variable that is not initialized.
But I am not seeing a variable in my code that is not initialized. I would really appreciate if someone could point out where I am mistaking.

I have the following code:

private EMA EMA1;
…
else if (State == State.Configure)
{
AddDataSeries(Data.BarsPeriodType.Minute, 5);
}
else if (State == State.DataLoaded)
{
EMA1 = EMA(BarsArray[1], 21);
}

protected override void OnBarUpdate()
{
if (CurrentBars[0] < 1 || CurrentBars[1] < 20)
return;

if(BarsInProgress == 0)
Value[0] = EMA1[0];
}

Thanks in advance!

2

You’re crossing over logic. Your EMA is on the 5 minute series so it updates every 5 minutes, but you’re assigning it from the other series which can start running as soon as there’s 1 bar on the chart. So if there’s 1 bar on the primary series, there perhaps isn’t any bar on the secondary.

I think that’s it.

3

Many thanks Several for your reply!

Event after modifying the following condition
protected override void OnBarUpdate()
{
if (CurrentBars[0] < 500 || CurrentBars[1] < 500)
return;

if(BarsInProgress == 0)
Value[0] = EMA1[0];
}

the same error essage appears again and the plateforme freezes.

4

Does it work if you remove this line:

Value[0] = EMA1[0];

5

When I remove the line
Value[0] = EMA1[0];
and attach the indicator on the chart, as expected, there is no line on the chart.
The plateforme does not freeze again.

6

How are you adding your plot?

	if (State == State.SetDefaults)
		{
		AddPlot(Brushes.Orange, "Plot1");
		}
		else if (State == State.Configure)
		{
			AddDataSeries(Data.BarsPeriodType.Minute, 5);
		}
		else if (State== State.DataLoaded)
		{
			EMA1 = EMA(BarsArray[1], 21);
		}
	}

	protected override void OnBarUpdate()
	{
	
		if (CurrentBars[1] < 22)
			return;
		
		if (BarsInProgress == 0 && CurrentBars[0] > 0)
    		Value[0] = EMA1[0];

	}

works for me

7

Many thanks Several for your help!
I have the line now on the chart with your modification!

...&& CurrentBars[0] > 0 was very important. Thanks again!

But the line on the chart is weird. It looks like stairs!!! Is that so OK?

8

It’s like that because you have 2 series with different intervals.

If you had a 1m primary and a 5m secondary, drawing the line as you are. You’d would see only a change in value every 5 bars so you would see flat line > jump > flat line > jump.