Price movement chart using text file as database

Hello, im looking for someone to make me a function in C#, so i can feed it a text file with prices and dates, ({PRICE}|{DATES}) this is how each of my text file lines looks like, so i want this function, to give average price per day (some days have more than 1 price in the entire day) so it can write in the chart the average price per day, thanks.