Question

我有一些有效的代码，但是将结果返回到文本框需要很长时间。输出可能需要20秒钟才能输出，而且我没有太多数据可以筛查。

我得到正确的输出，但是效果不好。

    Global variable:string newLine = Environment.NewLine;

    public List<string> AppointmentTypesForReport(int month)
    {
        List<string> appointments = new List<string>();

        string CS = ConfigurationManager.ConnectionStrings["U04i5a"].ConnectionString;
        using (MySqlConnection con = new MySqlConnection(CS))
        {
            try
            {
                con.Open();
                MySqlCommand cmd = con.CreateCommand();
                cmd.CommandText = "SELECT type FROM appointment WHERE MONTH(start) = @month";
                cmd.Parameters.AddWithValue("@month", month);
                cmd.ExecuteNonQuery();

                using (MySqlDataReader reader = cmd.ExecuteReader())
                {
                    while (reader.Read())
                    {
                        appointments.Add(reader["type"].ToString());
                    }
                }
            }
            catch (Exception)
            {
                throw;
            }
        }
        return appointments;
    }

    private void TypesByMonthRadioButton_CheckedChanged(object sender, EventArgs e)
    {
        ReportsTextBox.Clear();
        //resultTextBox.Text = string.Empty;

        var typesOutput = "";

        for (int m = 1; m <= 6; m++)
        {
            List<string> list = AppointmentTypesForReport(m);

            var j = from t in list
                    group t by t into g
                    let totalNumber = g.Count()
                    orderby totalNumber descending
                    select new { Returned = g.Key, Tally = totalNumber };

            typesOutput += newLine + DateTimeFormatInfo.CurrentInfo.GetMonthName(m) + newLine;

            //convert to lambda
            foreach (var t in j)
            {
                typesOutput += "Type of appointment scheduled: " + t.Returned + "   " + "-Appointments of this type: " + t.Tally + newLine;
            }
        }
        ReportsTextBox.Text = typesOutput;
    }

代码运行时，以下是文本框中的输出。

一月预定的约会类型：xyz-此类型的约会：2

2月

三月

四月

五月预定的约会类型：普通医生-此类型的约会：1

六月预定的约会类型：普通医生-此类型的约会：1

Answer 1

至少您应该使用StringBuilder来构建结果字符串：

 var typesOutput = new StringBuilder();
 ...
 //typesOutput += newLine + DateTimeFormatInfo.CurrentInfo.GetMonthName(m) + newLine;
 typesOutput.AppendLine();
 typesOutput.AppendLine(DateTimeFormatInfo.CurrentInfo.GetMonthName(m));
 ...
 //typesOutput += "Type of appointment scheduled: " + t.Returned + "   " + "-Appointments of this type: " + t.Tally + newLine;
 typesOutput.AppendFormat("Type of appointment scheduled: {0} - Appointments of this type:  {1}\n", t.Returned, t.Tally);
 ...
 ReportsTextBox.Text = typesOutput.ToString();

需要重构工作代码以提高速度

1 个答案: