Most MQL5 coders construct their buying and selling robots round a core trio of features: OnInit() , OnDeinit() , and OnTick() . Whereas this basis is important, it is like making an attempt to cook dinner a connoisseur meal with solely a pot, a pan, and a single burner. The MQL5 atmosphere affords a wealthy occasion mannequin with specialised handlers that may make your Skilled Advisors (EAs) and indicators extra environment friendly, interactive, and highly effective.
By venturing past the fundamentals, you may construct EAs that do not depend on each single tick, create dynamic person interfaces immediately on the chart, and even monitor and react to buying and selling exercise from different sources. Let’s discover three of essentially the most highly effective—and underutilized—occasion handlers: OnTimer() , OnChartEvent() , and OnTradeTransaction() .
Ditch the Tick: Constructing EAs with OnTimer()
The OnTick() occasion handler is the default workhorse for many EAs, executing its logic each time a brand new value quote arrives. That is nice for high-frequency methods however is extremely inefficient and pointless for methods designed for greater timeframes like H1, H4, or D1. Why verify your logic a number of instances a second if you solely care in regards to the state of a brand new bar as soon as an hour?
The OnTimer() occasion handler solves this downside. It permits you to create a customized, periodic set off on your code, utterly impartial of incoming ticks. 🕒
How It Works
Set the Timer: In your OnInit() perform, you name EventSetTimer(seconds) . This tells the terminal to begin producing a timer occasion each specified variety of seconds.
Execute the Logic: You place your buying and selling logic contained in the OnTimer() perform. This perform will now be referred to as on the interval you outlined.
Kill the Timer: In your OnDeinit() perform, you will need to name EventKillTimer() to cease the timer occasion when the EA is faraway from the chart. That is essential for stopping useful resource leaks.
Instance: A Non-Ticking EA for Increased Timeframes
Let’s construct a easy EA that checks for a brand new bar on the H1 timeframe each minute, relatively than on each tick.
#property copyright “Copyright 2025, EAHQ”
#property hyperlink “https://www.mql5.com/en/customers/michael4308”
#property model “1.00”
datetime lastBarTime = 0;
int OnInit()
{
EventSetTimer(60);
Print(“Timer EA Initialized. Checking for brand spanking new H1 bar each minute.”);
return(INIT_SUCCEEDED);
}
void OnDeinit(const int cause)
{
EventKillTimer();
Print(“Timer EA Eliminated. Timer stopped.”);
}
void OnTimer()
{
datetime newBarTime = (datetime)SeriesInfoInteger(_Symbol, PERIOD_H1, SERIES_LASTBAR_DATE);
if(newBarTime > lastBarTime)
{
lastBarTime = newBarTime;
Print(“New H1 Bar Detected at: “, TimeToString(newBarTime));
}
}
void OnTick()
{
}
By utilizing OnTimer() , this EA is much extra environment friendly. It solely consumes CPU sources as soon as a minute, leaving your terminal extra responsive and decreasing the processing load, which is particularly vital when working a number of EAs.
Making Charts Interactive with OnChartEvent()
Have you ever ever wished to let a person draw a line on a chart to set a take-profit stage or drag a rectangle to outline a buying and selling zone? The OnChartEvent() handler is your gateway to creating wealthy, interactive chart instruments. 🎨
This perform is a grasp listener that captures a variety of person interactions with the chart, akin to mouse clicks, key presses, and—most powerfully—interactions with graphical objects.
How It Works
The OnChartEvent() perform receives a number of parameters, however a very powerful are:
id : The kind of occasion that occurred (e.g., a key was pressed, an object was created).
lparam , dparam , sparam : Parameters containing detailed details about the occasion. Their which means relies on the id .
For object interactions, you will typically verify for these occasion IDs:
CHARTEVENT_OBJECT_CREATE : Fired when a person finishes drawing a brand new object.
CHARTEVENT_OBJECT_DRAG : Fired when a person drags an object throughout the chart.
CHARTEVENT_OBJECT_CLICK : Fired when a person clicks on an object.
Instance: Setting a Take-Revenue Degree with a Line
Let’s create an indicator that enables the person to attract a horizontal line. The indicator will then learn the worth stage of that line and print it to the Specialists log, simulating how an EA might use it to set a Take-Revenue.
#property copyright “Copyright 2025, EAHQ”
#property indicator_chart_window
void OnChartEvent(const int id,
const lengthy &lparam,
const double &dparam,
const string &sparam)
{
if(id == CHARTEVENT_OBJECT_CREATE)
{
Print(“Object Created: “, sparam);
if(ObjectType(sparam) == OBJ_HLINE)
{
double priceLevel = ObjectGetDouble(0, sparam, OBJPROP_PRICE, 0);
Print(“Take-Revenue stage set by HLine ‘”, sparam, “‘ at value: “, DoubleToString(priceLevel, _Digits));
}
}
if(id == CHARTEVENT_OBJECT_DRAG)
{
if(ObjectType(sparam) == OBJ_HLINE)
{
double priceLevel = ObjectGetDouble(0, sparam, OBJPROP_PRICE, 0);
Remark(“Present TP Degree: “, DoubleToString(priceLevel, _Digits));
}
}
}
This easy instance opens up a world of potentialities for creating intuitive, user-friendly buying and selling instruments that bridge the hole between handbook evaluation and automatic execution.
The Final Watchdog: OnTradeTransaction()
What in case your EA must learn about all the things taking place in your buying and selling account? This consists of handbook trades you place, trades executed by different EAs, and even actions taken by your dealer. The OnTradeTransaction() occasion handler is the final word watchdog, supplying you with real-time perception into all buying and selling exercise. 🕵️
This handler is triggered at any time when a commerce transaction happens on the account, akin to putting an order, modifying a stop-loss, closing a place, or a deal being executed.
How It Works
The OnTradeTransaction() perform receives three arguments:
trans : An MqlTradeTransaction construction containing detailed details about the transaction (kind, order ticket, value, quantity, and many others.).
request : The unique MqlTradeRequest that initiated this transaction.
consequence : The MqlTradeResult of executing the request.
You possibly can examine the trans.kind discipline to know what sort of transaction simply occurred. A typical and really helpful kind is TRADE_TRANSACTION_DEAL_ADD , which indicators {that a} new deal has been added to the account historical past (i.e., a commerce was executed).
Instance: Monitoring and Logging All New Trades
This is an EA that does nothing however monitor the account. When any new commerce (deal) is executed—whether or not by this EA, one other EA, or manually—it logs the main points.
#property copyright “Copyright 2025, EAHQ”
#property model “1.00”
void OnTradeTransaction(const MqlTradeTransaction &trans,
const MqlTradeRequest &request,
const MqlTradeResult &consequence)
{
if(trans.kind == TRADE_TRANSACTION_DEAL_ADD)
{
ulong deal_ticket = trans.deal;
if(HistoryDealSelect(deal_ticket))
{
lengthy deal_type = HistoryDealGetInteger(deal_ticket, DEAL_TYPE);
lengthy deal_magic = HistoryDealGetInteger(deal_ticket, DEAL_MAGIC);
double deal_volume = HistoryDealGetDouble(deal_ticket, DEAL_VOLUME);
string deal_symbol = HistoryDealGetString(deal_ticket, DEAL_SYMBOL);
PrintFormat(“New Deal Executed: Ticket #%d, Image: %s, Sort: %s, Quantity: %.2f, Magic: %d”,
deal_ticket,
deal_symbol,
(deal_type == DEAL_TYPE_BUY ? “Purchase” : “Promote”),
deal_volume,
deal_magic);
}
}
}
void OnInit() {}
void OnDeinit(const int cause) {}
void OnTick() {}
This handler is extremely highly effective. You possibly can construct:
A Commerce Supervisor: An EA that mechanically applies stop-loss and take-profit ranges to any commerce opened on the account, no matter its supply.
An Fairness Protector: An EA that displays for brand spanking new offers and closes all open positions if the account drawdown exceeds a sure threshold.
A Synchronization Software: An EA that copies trades from one account to a different in real-time.
By mastering these superior occasion handlers, you elevate your MQL5 coding from easy automation to creating really clever, environment friendly, and interactive buying and selling programs. Go forward and experiment—your buying and selling instruments won’t ever be the identical once more.
