大败在这一个自己写的类上，原来是对一些OOP的基本概念仍不清楚

最新推荐文章于 2025-06-07 19:24:53 发布

fenglei11

最新推荐文章于 2025-06-07 19:24:53 发布

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文章标签： oop integer string class database

本文链接：https://blog.youkuaiyun.com/fenglei11/article/details/5998178

本文介绍了一个使用Visual Basic .NET实现的公共类，该类根据当前时间动态生成不同的数据库连接字符串及SQL查询语句。具体包括根据分钟数选择不同数据库源及根据不同时间段构造特定的气象站数据查询。

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Public Class Class1 Private Shared min As Integer '定义一个静态数据成员 'Shared Sub New() ' min = System.DateTime.Now.Minute 'End Sub Private Sub New() End Sub Public Shared ReadOnly Property str_conn() As String Get Dim min As Integer = System.DateTime.Now.Minute 'min = System.DateTime.Now.Minute If min < 10 Then Return "Provider=SQLOLEDB;Data Source=172.23.64.146;" _ & "Database=elementinfo;User ID=aws;Password=aws1" Else Return "Provider=MSDAORA;Data Source=DXS;User ID=aws;Password=aws1234" End If End Get End Property Public Shared ReadOnly Property str_select() As String Get Dim obs_time As String Dim min As Integer = System.DateTime.Now.Minute If min < 10 Then obs_time = Now.ToString("yyyyMMddHH") Return "select longitude,latitude,precipitation,drybultemp,stationname " _ & "from tabstation,tabTimedata " _ & "where tabstation.stationnum = tabTimedata.stationNum " _ & "and tabStation.CityId=10 " _ & "and tabTimedata.ObservTimes=" _ & "'" & obs_time & "'" Else obs_time = Now.AddMinutes(-min Mod 10).ToString("yyyyMMddHHmm") Return "select lon,lat,precipitation,drybultemp,sname " _ & "from rdb_insert.t_base_station,rdb_insert.aws_Timedata " _ & "where rdb_insert.t_base_station.sno = rdb_insert.aws_Timedata.stationNum " _ & "and rdb_insert.t_base_station.area='西安地区' " _ & "and rdb_insert.aws_timedata.ObservTimes=" _ & "'" & obs_time & "'" End If End Get End Property End Class