.net - How to remove all lines in a file, then rewrite the file in Compact Framework 3.5 c# -

in .net framework using windows forms app can purge file, write data want file.

here code use in windows forms:

var openfile = file.opentext(fullfilename);             var fileempty = openfile.readline();             if (fileempty != null)             {                 var lines = file.readalllines(fullfilename).skip(4); //will skip first 4 rewrite file                 openfile.close();//close reading of file                 file.writealllines(fullfilename, lines); //reopen file write lines                 openfile.close();//close rewriting of file             }             openfile.close();             openfile.dispose(); 

i trying same thing compact framework. can keep lines want, , delete lines in file. not able rewrite file.

here compact framework code:

var sb = new stringbuilder();                  using (var sr = new streamreader(fullfilename))                 {                     // read first 4 lines nothing them; basically, skip them                     (int = 0; < 4; i++)                          sr.readline();                      string line1;                      while ((line1 = sr.readline()) != null)                     {                         sb.appendline(line1);                     }                 }                 string allines = sb.tostring();                  openfile.close();//close reading of file                 openfile.dispose();                  //reopen file write lines                 var writer = new streamwriter(fullfilename, false); //don't append!                 foreach (char line2 in allines)                 {                     writer.writeline(line2);                 }                 openfile.close();//close rewriting of file             }             openfile.close();             openfile.dispose(); 

your code

foreach (char line2 in allines) {     writer.writeline(line2); } 

is writing out characters of original file, each on separate line.

remember, allines single string happens have environment.newline between original strings of file.

what intend simply

writer.writeline(allines); 

update

you closing openfile number of times (you should once), not flushing or closing writer.

try

using (var writer = new streamwriter(fullfilename, false)) //don't append! {     writer.writeline(allines); } 

to ensure writer disposed , therefore flushed.