读取文件到List

I am needing to create a list of numbers from an uploaded file, if the numbers have "-" representing a range, I need to split the numbers, making the first number a start, iterate through til it gets to the second number. I know I will be storing the numbers in a List, I'm just not sure on how to break out the numbers in the file with "-", Here is an example of the file:I am needing to create a list of numbers from a