RemoveDrawObject does not remove User objects from the Chart

permalink · February 14th, 2015, 05:06 PM

Hi,

can it be the function RemoveDrawObject() does not delete objects which the user has added manually to the chart? I checked it many times and that far I do not see any problem/bug in the code. I can remove objects which the indicator created but when I try to remove an object which has been added by the user to the chart it does not work. Neither when I reference it by the tag, nor by the object id directly [RemoveDrawObject() has 2 overloads].

The behaving does not change if I lock/unlock the object or to what ever I assign it.

It looks for me NinjaTrader framework does not allow the C# code delete objects which have been created by the user.

Any ideas?

permalink · February 14th, 2015, 06:41 PM

AlBundy

Hi,

can it be the function RemoveDrawObject() does not delete objects which the user has added manually to the chart? I checked it many times and that far I do not see any problem/bug in the code. I can remove objects which the indicator created but when I try to remove an object which has been added by the user to the chart it does not work. Neither when I reference it by the tag, nor by the object id directly [RemoveDrawObject() has 2 overloads].

The behaving does not change if I lock/unlock the object or to what ever I assign it.

It looks for me NinjaTrader framework does not allow the C# code delete objects which have been created by the user.

Any ideas?

You can apply different indicators to your chart. When you use RemoveDrawObjects() within one indicator, it will not

- remove draw objects created via any other indicator or strategy
- remove draw objects that you have manually added

This is as expected.

You can remove manually added draw objects manually.

permalink · February 14th, 2015, 07:34 PM

Fat Tails

You can apply different indicators to your chart. When you use RemoveDrawObjects() within one indicator, it will not

- remove draw objects created via any other indicator or strategy
- remove draw objects that you have manually added

This is as expected.

You can remove manually added draw objects manually.

Good. This is the official function. Due the fact NT can delete all objects and it is not running as an OS in a privileged mode there is a function which can delete manually added draw objects.

Has somebody a control in mind I can start to check? It must be a non public method...

permalink · February 16th, 2015, 04:52 AM

SOLVED!

aiforus

1) Use Reflection to get extra information on undocumented methods and fields at runtime (write your own code in indicator)
2) Try to get extra information from NT .NET assemblies using software such as Reflector

Yes, Reflector was the key to success. I found a solution how to remove manually drawn objects from the chart:

Code

BindingFlags bfObject = BindingFlags.Instance | BindingFlags.NonPublic;
MethodInfo methodNT = typeof(ChartControl).GetMethod("RemoveDrawingObjectsAfterBar", bfObject);
methodNT.Invoke(this.ChartControl, new Object [] { 0 });

This method may not be for all suitable because it is deleting all drawn objects [also the objects drawn from any indicator] from the chart. I did not want to spend more time to investigate because it works for me.

Due the fact I have all drawn objects created by the indicator in an internal structure I just repaint them after calling the Invoke method and then I invalidate and refresh the chart. It goes that fast that it looks very smooth and indeed only the manually drawn objects are deleted.

If somebody finds a better solution please post it.

permalink · February 25th, 2017, 11:31 AM

Hi AlBundy,

I'm looking for a solution for the same problem. I would like to delete manually drawn traingle by indicator. Would you give me your code?

permalink · April 26th, 2020, 04:04 AM

AlBundy

Hi,

can it be the function RemoveDrawObject() does not delete objects which the user has added manually to the chart? I checked it many times and that far I do not see any problem/bug in the code. I can remove objects which the indicator created but when I try to remove an object which has been added by the user to the chart it does not work. Neither when I reference it by the tag, nor by the object id directly [RemoveDrawObject() has 2 overloads].

The behaving does not change if I lock/unlock the object or to what ever I assign it.

It looks for me NinjaTrader framework does not allow the C# code delete objects which have been created by the user.

Any ideas?

Hi

You can remove drawobjects individually.
If you use say "XYZ" +Current bar as your tag you can do the following
int numprior = num -1;
StringBuilder newstring = new StringBuilder();
newstring.Append("XYZ" + numprior);
string stringconvert = newstring.ToString();
RemoveDrawObject(stringconvert);
this removes the prior bar object.

I am sure there is a more elegant way but it's like using NT8 - beyond me!!

permalink · May 8th, 2020, 01:03 AM

Mindset

Hi

You can remove drawobjects individually.
If you use say "XYZ" +Current bar as your tag you can do the following
int numprior = num -1;
StringBuilder newstring = new StringBuilder();
newstring.Append("XYZ" + numprior);
string stringconvert = newstring.ToString();
RemoveDrawObject(stringconvert);
this removes the prior bar object.

I am sure there is a more elegant way but it's like using NT8 - beyond me!!

Edit - Sorry this doesn't quite work as expected - my bad.

RemoveDrawObject does not remove User objects from the Chart

Discussion in NinjaTrader

RemoveDrawObject does not remove User objects from the Chart