How To Get Current Argument And Value?

I'm using the chart control. And set it's zoom and scroll true.

Found a solution.

You will need to define your own derived class of CXTPChartControl, for example myCXTPChartCtrl
and in your derived class, for example, you defined OnLButtonDblClk function,

void myCXTPChartCtrl::OnLButtonDblClk( UINT nFlags, CPoint point )
{
   // here you get which point your mouse click at
   CXTPChartElement* hit =  HitTest ( point );

   // if the hitted element is valid type
   if( hit )
   {
       // if you want to check which data point your clicked on the chart series
       CXTPChartSeriesPoint* pPoint = DYNAMIC_DOWNCAST( CXTPChartSeriesPoint, hit );
      
       // if your hit is actually a point on the series
       if ( pPoint )
       {
            // do whatever you want, for example, get the actual value
           double value = pPoint->GetArgumentValue();
        }
    }
}

In the same way, you can get other types of element in the chart (for example, xAxis, yAxis, labels, chart series, markers, legends etc), remember everything is derived class of CXTPChartElement, so you only need to cast them to the type you want.

Happy coding!