How to Delete the last line of a file.txt

问题:

I'm reading a file.txt using StreamReader and writing using streamWriter.

? i'm inserting lines, but sometimes one of these inserts arestring.empty. Then It goes to anexception`that I created... In this exception, I want to delete that line I just inserted.

But I recreate the file, or something like that, I need just to remove/erase/delete the last line. May I do that ?

MyCode: IF you guys have another way to do this, i'd be very thankfull !

using (StreamWriter streamW = new StreamWriter(fileFinal, true)) { if (contador == numeroCampos) { contador = 0; }

  foreach (string s in clb_frente_impressao.Items)      {                                 if (camposEscritos >= 10 * numeroCampos)        {         streamW.WriteLine();         streamW.WriteLine("-------------------------------------------------------");         streamW.Write(nomearquivo + x.ToString());         streamW.WriteLine();         x++;         camposEscritos = 0;        }         if (contador >= clb_frente_impressao.Items.Count)           {             contador = 0;           }        switch (s)          {             case "numero_carteira":             if (campos_obrigatorios.Contains("numero_carteira") && campo.numero_carteira == "")                {                  dados_inexistentes++;                  skipToNext = true;                  break;                 }                 else if (campo.numero_carteira != "")                    {                       string aux = "";                       qtdZeros = Txt_qtdZeros.Text;                       if (qtdZeros == "")                         {                            qtdZeros = "8";                         }                    while (campo.numero_carteira.Length < Convert.ToInt32(qtdZeros))                        {                          campo.numero_carteira = campo.numero_carteira.Insert(0, "0");                        }                      if (usaC == "sim")                         {                       campos += @"\" + "*C" + aux + campo.numero_carteira + "*" + @"\";                                                 camposEscritos++;                          }                                             else                                             {                                                 campos += @"\" + "*" + aux + campo.numero_carteira + "*" + @"\";                                                 camposEscritos++;                                             }                                              if (contador == 0)                                             {                                                 streamW.WriteLine();                                                 streamW.Write("{0,-15}", campo.numero_carteira);                                                 contador++;                                             }                                             else                                             {                                                 streamW.Write("{0,-15}", campo.numero_carteira);                                                 contador++;                                             }                                         }                                        break;                                      case "matricula":                                        if (campos_obrigatorios.Contains("matricula") && campo.matricula == "")                                        {                                            dados_inexistentes++;                                            skipToNext = true;                                            break;                                        }                                         camposEscritos++;                                         if (campo.matricula != "")                                         {                                             if (campo.tipo_pessoa == "3")                                             {                                                 campos += @"\" + campo.matricula + "-" + campo.cod_dependente + @"\";                                              }                                             else                                             {                                                 campos += @"\" + campo.matricula + @"\";                                              }                                         }                                         if (contador > 0)                                         {                                             if (campo.cod_dependente != "")                                             {                                                 streamW.Write("{0,-10}", campo.matricula + "-" + campo.cod_dependente);                                                                                             contador++;                                             }                                             else                                             {                                                                                             streamW.Write("{0,-10}", campo.matricula);                                                 contador++;                                             }                                         }                                         else                                         {                                             if (campo.cod_dependente != "")                                             {                                                 streamW.WriteLine();                                                 streamW.Write("{0,-10}", campo.matricula + "-" + campo.cod_dependente);                                                 contador++;                                             }                                             else                                             {                                                 streamW.WriteLine();                                                 streamW.Write("{0,-10}", campo.matricula);                                                 contador++;                                             }                                         }                                         break;   if (skipToNext) break;                          } //Final do ForEach                          if (skipToNext)                         {                             //HERE IS WHERE I WANT TO DELETE THE LAST LINE THAT WAS WRITED BY streamW                             continue;                         } 

e.g: When It gets into case:"numero_carteira" and it's not empty,then it writes ok, but when I get to the matricula AND its empty, it will break and go to the exception I created. I want to delete the line there ;s Hope I could be clear !

回答1:

If the file is not too large, you can simply use this code:

var lines = File.ReadAllLines(pathToFile); File.WriteAllLines(pathToFile, lines.Take(lines.Length - 1)); 

So you have to write all lines except the last.

文章来源: How to Delete the last line of a file.txt