GridCtrl grid;

int minValue = INT_MAX;
int maxValue = INT_MIN;
int row = 5;
for(int i = 0; i < grid.GetColumnsCount(); i++)
{
    int v = grid(row, i);

    if(minValue > v)
       v = minValue;
    else if(maxValue < v)
       v = maxValue;
}

#include <CtrlLib/CtrlLib.h>
#include <GridCtrl/GridCtrl.h>

using namespace Upp;

#define LAYOUTFILE <MyProject/MyProject.lay>
#include <CtrlCore/lay.h>

LAYOUT(MyLayout, 428, 268)
	ITEM(GridCtrl, dv___0, HSizePosZ(116, 162).VSizePosZ(84, 84))
END_LAYOUT

class GridTrial : public WithMyLayout<StaticRect> {
...
};