File.Delete,删除文件时出现文件被另一个进程在用，无法删除?

Question

删除文件时出现文件被另一个进程在用，无法删除?
for (int j = 0; j < index; j++)
            {
                string path = @"D:\mail\MyTest" + j + ".txt";
                File.Delete(path);
            }

Answer 1

查一下代码，看哪里读了文件流，没有调用close方法关闭

Answer 2

已经关闭流了 
using (StreamWriter sw = new StreamWriter(dir, false, System.Text.Encoding.GetEncoding("GB2312")))
            {
                for (int i = 0; i < index; i++)
                {
                    string path = @"D:\mail\MyTest" + i + ".txt";
                    if (File.Exists(path))
                    {
                        StreamReader sr = new StreamReader(path, System.Text.Encoding.GetEncoding("GB2312"));
                        string line = "";
                        while ((line = sr.ReadLine()) != null)
                        {
                           if (line.StartsWith("date:"))
                            {
                                date = line.Trim().Replace("date", "发件日期") + "|";
                                sb.Append(date);
                            }
                            if (line.StartsWith("from:"))
                            {
                                from = line.Trim().Replace("from", "发件人邮箱") + "|";
                                sb.Append(from);
                            }
                            if (line.StartsWith("to:"))
                            {
                                to = line.Trim().Replace("to", "收件人邮箱") + "|";
                                sb.Append(to);
                            }
                            if (line.StartsWith("subject:"))
                            {
                                subject = line.Trim().Replace("subject:", "邮件名称:未送达") + "|";
                                sb.Append(subject);
                            }
                        }
                        strRep[0] = sb.ToString().Split('|')[2].ToString() + "|";//发件日期
                        strRep[1] = sb.ToString().Split('|')[0].ToString() + "|";//发件人邮箱
                        strRep[2] = sb.ToString().Split('|')[1].ToString() + "|";//收件人邮箱
                        strRep[3] = sb.ToString().Split('|')[3].ToString() + "|";//邮件名称
                        strRep[4] = "错误信息：" + strBody[0];                        sbNew.Append(strRep[0]);
                        sbNew.Append(strRep[1]);
                        sbNew.Append(strRep[2]);
                        sbNew.Append(strRep[3]);
                        sbNew.Append(strRep[4]);
                      
                        sw.Write(sbNew.ToString());
                        sb.Remove(0, sb.Length);
                        sbNew.Remove(0, sbNew.Length);
                        sw.WriteLine();
                    }
                }
                sw.Flush();
                sw.Close();
                sw.Dispose(); 
                          
            }
            for (int j = 0; j < index; j++)
            {
                string path = @"D:\mail\MyTest" + j + ".txt";
                File.Delete(path);
            }

Answer 3

你那个sw关闭了，那个sr并没有关闭啊
StreamReader sr = new StreamReader(path, System.Text.Encoding.GetEncoding("GB2312")); 
上面找不到关闭的语句