指标不自动更新？搞了几天实在不知代码哪里不对？求助.....

belief

#property strict
#property indicator_chart_window
#property indicator_buffers 2
#property indicator_plots 2
//--- plot shuzu1
#property indicator_label1  "shuzu1"
#property indicator_type1 DRAW_ARROW
#property indicator_color1  clrRed
#property indicator_style1  STYLE_SOLID
#property indicator_width1  3
//--- plot shuzu2
#property indicator_label2  "shuzu2"
#property indicator_type2 DRAW_ARROW
#property indicator_color2  clrGreen
#property indicator_style2  STYLE_SOLID
#property indicator_width2  3
//--- indicator buffers
double       shuzu1Buffer[];
double       shuzu2Buffer[];
//+------------------------------------------------------------------+
//| Custom indicator initialization function                      |
//+------------------------------------------------------------------+
int OnInit()
  {
//--- indicator buffers mapping
SetIndexBuffer(0,shuzu1Buffer);
SetIndexBuffer(1,shuzu2Buffer);
//--- setting a code from the Wingdings charset as the property of PLOT_ARROW
PlotIndexSetInteger(0,PLOT_ARROW,159);
PlotIndexSetInteger(1,PLOT_ARROW,159);
SetIndexEmptyValue(0,-1);
SetIndexEmptyValue(1,-1);
//---
return(INIT_SUCCEEDED);
  }

int OnCalculate(const int rates_total,
            const int prev_calculated,
            const datetime &time[],
            const double &open[],
            const double &high[],
            const double &low[],
            const double &close[],
            const long &tick_volume[],
            const long &volume[],
            const int &spread[])
  {
if(rates_total<=4) return(0);
int limit=rates_total-prev_calculated;
if(prev_calculated>0)  limit++;

for(int i=limit-3; i>=0; i--)
   {
   //shuzu1Buffer[i+1] = EMPTY_VALUE;
   //shuzu2Buffer[i+1] = EMPTY_VALUE;
   if(close[i+1]>close[i+2] && close[i]<open[i])
      {
      shuzu1Buffer[i+1]=high[i+1];
      }
   else
   {
      shuzu1Buffer[i+1]=0;
   }

   if(close[i+1]<close[i+2] && close[i]>open[i])
      {
      shuzu2Buffer[i+1]=low[i+1];
      }
   else
   {
      shuzu2Buffer[i+1]=0;
   }
   }
//  ChartSetSymbolPeriod
return(rates_total);
  }