c# 4.0 - Writing files in windows phone 8 -

i want read , write data text file in windows phone 8 application. tried code

isolatedstoragefile isf = isolatedstoragefile.getuserstoreforapplication(); streamwriter wr = new streamwriter(new isolatedstoragefilestream("file.txt", filemode.openorcreate, isf)); wr.writelineasync("hello"); wr.close(); 

but nothing. please me out of problem. thanks.

write data file:

isolatedstoragefile myisolatedstorage = isolatedstoragefile.getuserstoreforapplication();  //create new file using (streamwriter writefile = new streamwriter(new isolatedstoragefilestream("myfile.txt", filemode.create, fileaccess.write, myisolatedstorage))) {    string sometextdata = "this text data saved in new text file in isolatedstorage!";    writefile.writeline(sometextdata);    writefile.close(); } 

read data file:

isolatedstoragefile myisolatedstorage = isolatedstoragefile.getuserstoreforapplication(); isolatedstoragefilestream filestream = myisolatedstorage.openfile("myfile.txt", filemode.open, fileaccess.read); using (streamreader reader = new streamreader(filestream)) {          //visualize text data in textblock text      this.text.text = reader.readline(); } 

go through links: http://www.geekchamp.com/tips/all-about-wp7-isolated-storage-read-and-save-text-files

https://www.google.co.in/#q=wp8+isolated+storage+geek