You have to advance to the next line, you can use a while
-loop:
using (var sr = new StreamReader(file))
{
string fileLine;
while ((fileLine = sr.ReadLine()) != null)
{
foreach (string piece in fileLine.Split(','))
{
listView1.Items.Add(piece);
}
}
}
Note that you don't need to close the stream manually, that is done by the using-statement.
Another way is using File.ReadLines
or File.ReadAllLines
which can help to simplify your code:
var allPieces = File.ReadLines(file).SelectMany(line => line.Split(','));
foreach(string piece in allPieces)
listView1.Items.Add(piece);