Excel read cell is empty?

Hey guys my Problem is when i read the cell and in the cell is nothing i have an error how can i check that?

var aExcel = sh.Cells[26, 2].Value.ToString();
 double test = Convert.ToDouble(aExcel);

and a other question how can i read more cells ? because my code is so long …

var aExcel = sh.Cells[26, 2].Value.ToString();
var bExcel = sh.Cells[27, 2].Value.ToString();
var cExcel = sh.Cells[28, 2].Value.ToString();
var dExcel = sh.Cells[29, 2].Value.ToString();
var eExcel = sh.Cells[30, 2].Value.ToString();
var fExcel = sh.Cells[31, 2].Value.ToString();
double test1 = Convert.ToDouble(aExcel);
double test2 = Convert.ToDouble(bExcel);
double test3 = Convert.ToDouble(cExcel);
double test4 = Convert.ToDouble(dExcel);
double test5 = Convert.ToDouble(aExcel);

>Solution :

You can check like this:

 if(sh.Cells[26, 2] != null)
{
//do something
}

code:

double test;
var aExcel = sh.Cells[26, 2];
if(aExcel != null){
test = Convert.ToDouble(aExcel.Value.ToString());
}