Assuming the only time the space character can be used as the delimiter you can read your flat file one line at a time, then split by Space
using (StreamReader sr = File.OpenText(Filepath))
{
string line = String.Empty;
while ((line = sr.ReadLine()) != null)
{
string[] values = line.Split(' ');
MessageBox.Show(values[0])
MessageBox.Show(values[1])
MessageBox.Show(values[2])
}