Question

我想从已经在数据库中输入的日期开始每两周创建一个任务提醒（用户将其添加到具有开始日期点的数据库）。根据一周中的一天的位置，我试了一下，但没有用，如果有人有想法我会很感激

cmd5.CommandText = "select * from task where frequence='2W' "
    da5.SelectCommand = cmd1
    da5.Fill(ds5, "0")
    DataGridView6.Columns.Add("fr", "fr")
    DataGridView6.Columns.Add("class", "class")

    For i As Integer = 0 To ds5.Tables(0).Rows.Count - 1
        If Date.Now.DayOfWeek > 3 Then
            If CType(ds5.Tables(0).Rows(i).Item(3), Date).DayOfWeek = Date.Now.DayOfWeek Or CType(ds5.Tables(0).Rows(i).Item(3), Date).DayOfWeek - ???? = Date.Now.DayOfWeek Then
                DataGridView6.Rows.Add(ds5.Tables(0).Rows(i).Item(4), CType(ds5.Tables(0).Rows(i).Item(3), Date).DayOfWeek)
            End If
        End If
        If Date.Now.DayOfWeek < 4 And Date.Now.DayOfWeek <> 0 Then
            If CType(ds5.Tables(0).Rows(i).Item(3), Date).DayOfWeek = Date.Now.DayOfWeek Or CType(ds5.Tables(0).Rows(i).Item(3), Date).DayOfWeek + ???? = Date.Now.DayOfWeek Then
                DataGridView6.Rows.Add(ds5.Tables(0).Rows(i).Item(4), CType(ds5.Tables(0).Rows(i).Item(3), Date).DayOfWeek)
            End If
        End If
    Next

in“??????”我不知道我能拿什么来获得正确的结果!!请有人帮帮我！

Answer 1

正如我从您的评论中所理解的，您只对区间分析部分感兴趣，即确定今天的日期是否在数据库中定义的给定条件之前/之后（使用start_date和{ {1}}）。这里有一个示例代码来处理这个问题：

frequency

上面的代码会检查当前日期是否等于（或晚于）Dim start_date As Date = Now.AddDays(-14) 'start_date value to be taken from the DB Dim frequency As TimeSpan = TimeSpan.FromDays(14) 'Number of days as a function of the given frequency in your DB; this is for 2W. Dim elapsedDays As TimeSpan = Now.Subtract(start_date) If (elapsedDays >= frequency) Then 'NOTIFY USER -> it has passed, at least, "frequency" number of days from "start_date" If (elapsedDays > frequency) Then Dim addDays As Integer = elapsedDays.Subtract(frequency).Days Dim dateWhenTargetMet As Date = Now.AddDays(-addDays) 'Tell user that the target was met "addDays" ago, on "dateWhenTargetMet" End If End If + start_date天数。

我如何在vb.net中创建每两周一次任务的提醒

1 个答案: