How to know if an arrow exists on the previous bar?

[sixteencorners]

My indicator occasionally draws up arrows like this:

DrawArrowUp("MyArrowUp" + CurrentBar, false, 0, y, Color.Black);

I would like to know if there is such an arrow on the previous bar, and if yes, do something.

Something like:
if (DrawArrowUp("MyArrowUp" + CurrentBar - 1) exists
then do something

Thanks

[bltdavid]

My indicator occasionally draws up arrows like this:

DrawArrowUp("MyArrowUp" + CurrentBar, false, 0, y, Color.Black);

I would like to know if there is such an arrow on the previous bar, and if yes, do something.

Something like:
if (DrawArrowUp("MyArrowUp" + CurrentBar - 1) exists
then do something

In what context?

From within the same indicator?
From within a different indicator?
From within a strategy?

Did you write this indicator?
Can you attach the source of your indicator?

Drawing an Up arrow or Down arrow does not, by definition, leave a "breadcrumb" for you to interrogate later to see if an arrow was drawn. You'll have to design your own "breadcrumb" code so that you can check if an arrow exists, and on what bar (if you need that, too).

Such code is not hard, but the design can vary based upon the context in which you want to do the future interrogation. For example, if you want to check this from a strategy, the usual way is leave "breadcrumbs" using a DataSeries or a BoolSeries.

If someone else wrote the indicator, chances are this "breadcrumb" code may already be in there. But if you're the sole author, then you'll need to write it yourself.

[NinjaTrader_PaulH]

Hello sixteencorners,

Thanks for your post.

Member bltdavid has offered some valued considerations.

One approach you could take would be to create an int variable to store the bar number of where the last arrow was drawn and then your code would test to see if the current bar minus the saved bar is equal to 1 indicating that indeed an arrow was applied on the previous bar. The value of CurrentBar is the bar number (Reference: http://ninjatrader.com/support/helpG...currentbar.htm) of the bar being processed.

For example, assume you have created an integer variable called savedBar.

if (Your conditions to draw arrow)
{
DrawArrowUp("MyArrowUp" + CurrentBar, false, 0, y, Color.Black);
savedBar = CurrentBar; // store the bar the latest arrow is drawn on
}

if ((CurrentBar - savedBar) == 1)
{
// do something here
}

[sixteencorners]

Thank you, problem solved. So easy it is embarrassing!