I have to build a C# program that makes CSV files and puts long numbers (as string in my program). The problem is, when I open this CSV file in Excel the numbers appear like this:

1234E+ or 1234560000000 (the end of the number is 0)

How I retain the formatting of the numbers? If I open the file as a text file, the numbers are formatted correctly.

Thanks in advance.

c# excel
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