主题：[求助]目录树如何与课程表相连？

'报错是因为datetimepicker没有值导致的，可以限制下

Dim dtp As WinForm.DateTimePicker
dtp = e.Form.Controls("DateTimePicker1")
If dtp.Value IsNot Nothing Then
    Dim wday As Integer = dtp.Value.DayOfWeek
    Dim wdays() As Integer={wday-1,wday-2,wday-3,wday-4,wday-5,wday-6,wday-7}
    Dim dweek() As String={"星期一","星期二","星期三","星期四","星期五","星期六","星期日"}
    Dim classTime() As String={"8:00-9:00","9:00-10:00"}
    Dim dt As DataTable
    dt=DataTables("表A")
    For i As Integer=0 To dt.DataRows.Count-1
        For j As Integer=0 To dweek.length-1
            dt.DataRows(i)(dweek(j))=Nothing
        Next
    Next
    For i As Integer=0 To 6
        dt.DataCols(dweek(i)).Caption=dweek(i) & "_" & dtp.Value.AddDays(-wdays(i))
        For j As Integer =0 To classTime.length-1
            Dim drlist As List(of DataRow)=DataTables("排课明细").Select("日期 = #" & dtp.Value.AddDays(-wdays(i)) & "# and 上课时间 = '" & classTime(j) & "'")
            If not drlist Is Nothing Then
                For k As Integer = 0 To drlist.Count-1
                    If k=0 Then
                        dt.DataRows(j)(dweek(i))=drlist(k)("课程名称")
                    Else
                        dt.DataRows(j)(dweek(i))=dt.DataRows(j)(dweek(i)) & "," & drlist(k)("课程名称")
                    End If
                Next
            End If
           
        Next
    Next
    dt.BuildHeader()
End If