How to draw a horizontal line in OnCalculate function

External question — Stack Overflow Stack Exchange Author: user1451111 Original post: https://stackoverflow.com/questions/78098102 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. The question is about MQL4 language for MetaTraders 4 platform. I want to draw a horizontal line. I found the below mentioned snippet somewhere online and am trying to use it inside OnCaculate() function to draw a horizontal line on, let's say the maximum value in last 5 minutes. int i; //let's assume it has a valid value for the highest value index if (!ObjectCreate(0, "HLine", OBJ_HLINE, 0, 0, High[i])) { Print(__FUNCTION__, ": Failed to create a horizontal line! Error code =", GetLastError()); return (false); } I see this error in the log window: OnCalculate: Failed to create a horizontal line! Error code = 4200 What is wrong in this snippet? If it is incorrect, please guide me with a correct way.

External answer — Stack Overflow Stack Exchange Author: Mark SdS Original post: https://stackoverflow.com/a/78105519 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. Error 4200 means Object already exists : see error codes So you'll need to ObjectDelete(0, "HLine") first.