If the date is saved in the title of the file then you can use the following code to search for it:
var appStorage = IsolatedStorageFile.GetUserStoreForApplication();
string date = appStorage.GetFileNames("the date you are looking for")
In answer to your other question if you use .Write()
when writing text to a file, then it will create one long stream of data, if you use .WriteLine()
then you will write the information, then a new line reference will be added at the end.
I'm not sure as you weren't very clear, but just in-case, here is a general procedure for reading files from IsolatedStorage:
var appStorage = IsolatedStorageFile.GetUserStoreForApplication();
using (StreamReader reader = new StreamReader(appStorage.OpenFile(fileName, FileMode.Open, FileAccess.Read)))
{
fileContent = reader.ReadToEnd();
}