类型＆＃39; System.NullReferenceException＆＃39;的例外情况发生在WebApplication13.dll中但未在用户代码中处理

Question

for (i in uitgaven)
{

   for(n=0;n<data.length;++n)// iterate row by row and examine data in column A
   { 

     if(data[n][3].toString().match(uitgaven[i][0])==uitgaven[i][0]){ data[n][4] = uitgaven[i][1]
   };

}