Getting the max and min price of current chart - mql4

Question

After performing
ChartNavigate(0, CHART_END, -5142);
I want to get the max and min price of that particular chart.
I tried
ChartGetDouble(0,CHART_PRICE_MAX,0,top)
ChartGetDouble(0,CHART_PRICE_MIN,0,top)
WindowPriceMax
WindowPriceMin
None of them gives me the price after the ChartNavigate.
What is the right way to do this?

Answer 1

New-MQL4.56789 features may surprise, nevertheless:
Step 0: always catch Chart_OkFLAG
bool Chart_OkFLAG;
double Chart_min,
Chart_MAX;
int Chart_ToBeMODIFIED = ChartID();
int Chart_ToBeMODIFIED_SubWinID = 0;
int Chart_nBarsRelativeSHIFT = 0;
Chart_OkFLAG = ChartNavigate( Chart_ToBeMODIFIED,
< CHART_BEGIN |
CHART_END |
CHART_CURRENT_POS >,
Chart_nBarsRelativeSHIFT
);
If OK: you won the first round, the GUI command has been accepted for being syntactically & context-wise correct. That does not mean, it was executed by the GUI processor. It was just let in, to the tail of the GUI-command-QUEUE.
Step 1: Enforce it's execution ( wise to think about deferring such processing to some safe place, after mission-critical elements have been fulfilled )
if ( Chart_OkFLAG ){
WindowRedraw(); // ol'-MQL4
ChartRedraw( Chart_ToBeMODIFIED ); // new-MQL4
Chart_min = ChartPriceMin( Chart_ToBeMODIFIED,
Chart_ToBeMODIFIED_SubWinID
);
Chart_MAX = ChartPriceMAX( Chart_ToBeMODIFIED,
Chart_ToBeMODIFIED_SubWinID
);
}
else{
// ERROR HANDLING onChartNavigate(T)ERROR
}
ALWAYS: do not hesitate to inline error handlers, even where MQL4 language seems straightforward ( you never know, when that effort pays off by avoiding hours of bug tracking )
double ChartPriceMin( const long Chart_ID = 0,
const int Chart_SubWindow_ID = 0
) {
double result = EMPTY_VALUE;
ResetLastError();
if ( !ChartGetDouble( Chart_ID,
CHART_PRICE_MIN,
Chart_SubWindow_ID,
result
)
){
PrintFormat( "ERROR: Code(%d) in [%s]",
GetLastError(),
__FUNCTION__,
);
}
return( result );
}
double ChartPriceMAX( const long Chart_ID = 0,
const int Chart_SubWindow_ID = 0
) {
double result = EMPTY_VALUE;
ResetLastError();
if ( !ChartGetDouble( Chart_ID,
CHART_PRICE_MAX,
Chart_SubWindow_ID,
result
)
){
PrintFormat( "ERROR: Code(%d) in [%s]",
GetLastError(),
__FUNCTION__,
);
}
return( result );
}