如果条件为真，则中断或关闭 sqlDatareader 并退出使用 (SqlDataReader rdr = cmd.E

本文关键字：退出 SqlDataReader rdr cmd sqlDatareader 条件 中断 如果 | 更新日期: 2023-09-27 17:56:47

using (SqlDataReader rdr = cmd.ExecuteReader())
{
    while(rdr.Read())
    {
        DateTime dt2 = Convert.ToDateTime(rdr["Date"]);
        int Classroom = Convert.ToInt32(rdr["ClassroomNo"]);
        TimeSpan ST = (TimeSpan)rdr["StartingTime"];
        TimeSpan ET = (TimeSpan)rdr["EndingTime"];
        TimeSpan span = ET.Subtract(ST);
        double Minutesdifference = span.TotalMinutes;
        TimeSpan NewTime = (TimeSpan)rdr["StartingTIme"];
        for (int i = 1; i <= Minutesdifference; i++)
        {
            NewTime = NewTime.Add(TimeSpan.FromMinutes(1));
            // Response.Write(NewTime + "<br>");
            Response.Write(Classroom + "<br>");
            Response.Write(ClassroomNo + "<br>");
            Response.Write(dt + "<br>");
            Response.Write(dt2 + "<br>");
            Response.Write(StartTime + "<br>");
            Response.Write(NewTime + "<br>");
            Response.Write(ST + "<br>");
            if ((Classroom == ClassroomNo && dt == dt2 && StartTime == NewTime) || (Classroom == ClassroomNo && dt == dt2 && StartTime == ST))
            {
                flag = 1;
                break;
            }
            else
            {
                flag = 0;
            }
        }
    }
}
if (flag == 0)
{
    SqlCommand cmd2 = new SqlCommand("spStoreTimeSlotDetails2", con);
    cmd2.CommandType = CommandType.StoredProcedure;
    cmd2.Parameters.AddWithValue("@Username", hfUsername.Value);
    cmd2.Parameters.AddWithValue("@EmpName", lblFacultyName.Text);
    cmd2.Parameters.AddWithValue("@Date", dt);
    cmd2.Parameters.AddWithValue("@Day", day);
    cmd2.Parameters.AddWithValue("@ST", StartTime);
    cmd2.Parameters.AddWithValue("@ET", EndTime);
    cmd2.Parameters.AddWithValue("@TimeSlot", hfTmeSlot.Value);
    cmd2.Parameters.AddWithValue("@Topic", txtTopic.Text);
    cmd2.Parameters.AddWithValue("@ClassroomNo", ClassroomNo);
    cmd2.ExecuteNonQuery();
    lblMessage.ForeColor = System.Drawing.Color.Green;
    lblMessage.Text = "Data Saved Successfully";
}
else if (flag == 1)
{
    lblMessage.ForeColor = System.Drawing.Color.Red;
    lblMessage.Text = "Time Slot already allocated by some other Employee. Please choose another";
}

我将 If 条件写入 for 循环。如果该条件为 true，则中断 for 循环，但while(rdr.Read())方法仍在执行。我只想关闭 Reader 方法并直接从using(sqlDataReader rdr=cmd.ExecuteReader)方法中出来并执行 if（flag==0）。

如果条件为真，则中断或关闭 sqlDatareader 并退出使用 (SqlDataReader rdr = cmd.E

我的假设是，在脱离for循环后，你仍然想在if loop of flag中执行代码，所以只需添加这段代码就可以打破rdr.Read() while循环

else if (flag == 1)
{
  lblMessage.ForeColor = System.Drawing.Color.Red;
  lblMessage.Text = "Time Slot already allocated by some other Employee. Please choose another";
   break;
 }

此代码将确保释放和关闭 Reader 对象：

using (SqlDataReader rdr = cmd.ExecuteReader())

因此，除了建议的更改之外，不需要太多

while (reader.Read() && !flag)
{
     ....
     for (int i = 1; i <= Minutesdifference; i++)
     {
           if ((Classroom == ClassroomNo && dt == dt2 && StartTime == NewTime) || (Classroom == ClassroomNo && dt == dt2 && StartTime == ST))
                            {
                                flag = 1;
                                break;
                            }
                           else
                           {flag=0;}
                        ...
     }
}

正如谢尔盖·叶夫拉科夫所建议的，在 while 循环之前将标志变量设置为 0，如下所示。

using (SqlDataReader rdr = cmd.ExecuteReader())
{
    flag=0;
    while (reader.Read() && !flag)
    {
          .....
           for (int i = 1; i <= Minutesdifference; i++)
           {
                    if ((Classroom == ClassroomNo && dt == dt2 && 
                    StartTime== NewTime) || (Classroom == ClassroomNo && 
                    dt == dt2 && StartTime == ST))
                    {
                            flag = 1;
                            break;
                    }
                    //no need of else part here now.
                    ...
            }
    }
}
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