c# - Avoid "file in use by another process" IO exception -

the code have included below writes csv file. if csv file writing happens open in excel, system.io.exception indicates "the file being used process."

how can change code program continuing running , wait until csv no longer open in excel?

private void timer1_tick(object sender, eventargs e)     {         int actmonth, actyear, actsecond;         system.datetime fecha = system.datetime.now;         actmonth = fecha.month;         actyear = fecha.year;         if (actmonth <= 9)         {             valorfechaact = system.convert.tostring(actyear) + "00" + system.convert.tostring(actmonth);         }         else         {             valorfechaact = system.convert.tostring(actyear) + "0" + system.convert.tostring(actmonth);         }          actsecond = fecha.second;          string label;         label = label1.text;         string @ = "@";         string filename = valorfechaact + ".csv";          string ruta3 = system.io.path.combine(at, label, filename);          if (directory.exists(label1.text))         {             streamwriter wr = new streamwriter(ruta3, true);             wr.writeline("1asd" + actsecond);             wr.close();             wr.dispose();         }         else         {             system.console.writeline("no se puede escribir en el archivo");             timer1.stop();         }     } 

you can write methode try open file filestream , return boolean flag

a possible solution

public static class fileinfoextension {     public static bool islocked(this fileinfo file)     {         filestream stream = null;         try         {             stream = file.open(filemode.open, fileaccess.read, fileshare.none);         }         catch (ioexception)         {             return true;         }                 {             stream?.close();         }         return false;     } } 

then can use

    var fileinfo = new fileinfo(ruta3);     if (!fileinfo.islocked())     {        // code     } 

a simple (and bad) solution wait is

    while (file.islocked())     {        thread.sleep(100);     } 

general code unclear , difficult read.

you have redudant code , few variable bad named. maybe guidline can https://github.com/dennisdoomen/csharpguidelines

maybe little bit clearer solution is

    private void timer1_tick(object sender, eventargs e)     {         var directory = label1.text;         if (!directory.exists(directory))         {             console.writeline("no se puede escribir en el archivo");             timer1.stop();             return;         }         var = datetime.now;         _valorfechaact = now.month <= 9 ? $"{now.year}00{now.month}" : $"{now.year}0{now.month}";         var fullname = path.combine("@", directory, $"{_valorfechaact}.csv");         var fileinfo = new fileinfo(fullname);         if (fileinfo.islocked())         {             console.writeline($"the file {fullname} locked!");             return;         }         using (var wr = new streamwriter(fullname, true))         {             wr.writeline("1asd" + now.second);         }     } 

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