EVENT handling function not fund, help-me

[le0max12]

I cant found the error, here is the code. i want to use this file to import in another 

string CheckSignal()
{
MqlRates PriceInfo[];
ArraySetAsSeries(PriceInfo,true);
int Data = CopyRates(Symbol(),Period(),0,3,PriceInfo);
string signal="";
double MiddleBandArray[];
double UpperBandArray[];
double LowerBandArray[];

ArraySetAsSeries(MiddleBandArray,true);
ArraySetAsSeries(UpperBandArray,true);
ArraySetAsSeries(LowerBandArray,true);

int BollingerBandsDefinition = iBands(_Symbol,_Period,20,0,2,PRICE_CLOSE);

CopyBuffer(BollingerBandsDefinition,0,0,3,MiddleBandArray);
CopyBuffer(BollingerBandsDefinition,1,0,3,UpperBandArray);
CopyBuffer(BollingerBandsDefinition,2,0,3,LowerBandArray);

double myMiddleBandValue0=MiddleBandArray[0];
double myUpperBandValue0= UpperBandArray[0];
double myLowerBandValue0=LowerBandArray[0];
 if(myMiddleBandValue0<PriceInfo[0].open)
   {
      signal="buy";
   }
return signal;

[WindmillMQL]

le0max12:
I cant found the error, here is the code. i want to use this file to import in another 

I don't think that anybody can help you if you don't specify what error message you received.

[William Roeder]

le0max12: I cant found the error,

int BollingerBandsDefinition = iBands(_Symbol,_Period,20,0,2,PRICE_CLOSE);
CopyBuffer(BollingerBandsDefinition,0,0,3,MiddleBandArray);

Perhaps you should read the manual, especially the examples. They all (including iCustom) return a handle (an int.) You get that in OnInit. In OnTick (after the indicator has updated its buffers,) you use the handle, shift and count to get the data.
          Technical Indicators - Reference on algorithmic/automated trading language for MetaTrader 5
          Timeseries and Indicators Access / CopyBuffer - Reference on algorithmic/automated trading language for MetaTrader 5
          How to start with MQL5 - General - MQL5 programming forum - Page 3 #22 2020.03.08
          How to call indicators in MQL5 - MQL5 Articles 12 March 2010

Also see my example for encapsulating calls
          Detailed explanation of iCustom - MQL4 programming forum 2017.05.23