read and display long numbers in c# from CSV

Question

i have a csv file like so

CSV FILE

Peter,5.00052E+11

and in my c# i am reading and then displaying them like so:

C#

using (StreamReader sr = new StreamReader(pathFileName))
 {
    string[] cols ;
    while (sr.Peek() != -1)
    {
       cols = split(",")      
    }
      MessageBox.Show(cols[1]);
  }

the output i get is 5.00052E+11 but the number that shows up in my excel is 500051882871

i have tried converting it into double in c# but it gives me just a bunch of zeros i am also fairly new to c# so any help would be appreciated