c# - saveFileDialog generates 2 file instead 1? -

i not understand why generates 2 files instead of one: have same names, 1 (that ok) has right extension (extension) , xxxxbytes, while other has no extension (file type is) , 0bytes.

stream my1stream; savefiledialog savefiledialog1 = new savefiledialog();  savefiledialog1.filter = "txt files (*.txt)|*.txt|all files (*.*)|*.*"; savefiledialog1.filterindex = 2; savefiledialog1.restoredirectory = true;  if (savefiledialog1.showdialog() == dialogresult.ok) {     if ((my1stream = savefiledialog1.openfile()) != null)     {         fileout = savefiledialog1.filename + extension;             passwordbytes = getpasswordbytes();         my1stream.close();         aes.encryptfile(filein, fileout, passwordbytes);         messagebox.show("file criptato!");     } } 

the extension derived filein (in openfiledialog) , declared in form: private string extension :

filein = openfiledialog1.filename;  extension = path.getextension(filein); 

from msdn page on savefiledialog.openfile method

for security purposes, method creates new file selected name , opens read/write permissions. can cause unintentional loss of data if select existing file save to

so line

if ((my1stream = savefiledialog1.openfile()) != null) 

creates file name selected , 0 bytes. code continues creating file in aes.encryptfile call tne name of fileout

you write

if (savefiledialog1.showdialog() == dialogresult.ok) {     fileout = savefiledialog1.filename;         passwordbytes = getpasswordbytes();     aes.encryptfile(filein, fileout, passwordbytes);     messagebox.show("file criptato!"); }