private void btnImport_Click(object sender, EventArgs e)
        {
            string filePath = textBox1.Text;
            string importPwd = txtPwd.Text;
            if (string.IsNullOrEmpty(filePath) || string.IsNullOrEmpty(importPwd))
            {
                MessageBox.Show("请先导入文件,填写操作密码后,再操作！");
            }
            else
            {
                btnImport.Text = "正在导入...";
                btnImport.Enabled = false;
                string[] allLines = File.ReadAllLines(filePath);
                using (SQLiteConnection con = new SQLiteConnection(connStr))
                {
                    con.Open();
                    DbTransaction trans = con.BeginTransaction();//开始事务   
                    SQLiteCommand cmd = new SQLiteCommand(con);
                    try
                    {
                        for (int n = 0; n < allLines.Length; n++)
                        {
                            cmd.CommandText = "insert into imei(imei) values(@imei)";
                            cmd.Parameters.Add(new SQLiteParameter("@imei", DbType.String));
                            cmd.Parameters["@imei"].Value = allLines[n];
                            cmd.ExecuteNonQuery();
                        }
                        trans.Commit();//提交事务   
                        MessageBox.Show("文件导入成功！");
                    }
                    catch (Exception ex)
                    {
                        trans.Rollback();
                        MessageBox.Show("文件导入错误，请检查是否重复导入或其它原因！");

                    }
                    finally
                    {
                        btnImport.Text = "导  入";
                        btnImport.Enabled = true;
                    }
                }
            }
        }