我采用了一种更 OOP 的方法,就 Timers 而言可能更经济,但界面非常简单。核心是一个跟踪作业和时间的TaskItem,然后是一个集合类来公开它们、启动它们和停止它们。通过将尽可能多的功能隐藏在尽可能低的级别,事情会变得更简单。
我只使用了一个计时器,但不明白为什么您需要多个计时器来完成一项任务。如果 TaskItem 记录了DateTime
它的启动时间(这在我的创建时会自动发生),那么您根本不需要任何计时器。Elapsed 始终使用StartedTime
and DateTime.Now
(对于正在运行的任务)或CompletedTime
已完成的任务来计算。我看不到计时器在哪里添加了任何东西。
你必须为你的目的制作许多模组。这不会保存已完成的项目,也不会从列表中删除它们,但可能会给您一个开始的地方。这也是第一次通过的事情;这里和那里肯定存在问题。
Imports System.Collections.ObjectModel
Public Class Tasks
' slight overkill
Private Enum LVGroups
Running
Completed
End Enum
Public Enum TaskJobs
SweepFloor
BuildRobot
CleanOven
RepairRobot
EmptyTrash
TeachRobotToTalk
MakeCoffee
TeachRobotToWalk
WashDishes
TeachRobotVisualBasic
End Enum
' class for a single task
Public Class TaskItem
' these ought to be readonly; so no cheating
Public Property ID As String
Public Property EmpName As String
Public Property StartedTime As DateTime
Public Property CompletedTime As DateTime
' or job code...
Public Property Job As TaskJobs
' put in a ClassLib or Namespace
Friend Sub New(sName As String, tj As TaskJobs)
EmpName = sName
Job = tj
StartedTime = DateTime.Now
CompletedTime = DateTime.MaxValue
ID = System.Guid.NewGuid.ToString
End Sub
Public Function IsActive() As Boolean
Return (CompletedTime = DateTime.MaxValue)
End Function
Public Sub EndTask()
CompletedTime = DateTime.Now
End Sub
Public Function GetElapsed() As String
Dim t As TimeSpan
If IsActive() Then
t = DateTime.Now - StartedTime
Else
t = CompletedTime - StartedTime
End If
Return String.Format("{0:00}:{1:00}:{2:00}", Math.Floor(t.TotalHours),
t.Minutes, t.Seconds)
End Function
Public Overrides Function ToString() As String
Return String.Format("{0} {1} {2}", EmpName, Job.ToString, GetElapsed)
End Function
End Class
Private col As Collection(Of TaskItem)
Private myLV As ListView
' assign the LV when tasks are created
Public Sub New(lvTask As ListView)
myLV = lvTask
col = New Collection(Of TaskItem)
End Sub
' add new task with EmpName and JobCode
Public Sub NewTask(sName As String, tj As TaskJobs)
Dim ti As New TaskItem(sName, tj)
col.Add(ti)
' LV layout: empname, job, elapsed, ID
' but only 3 columns so that ID is "hidden"
Dim lvi As New ListViewItem(ti.EmpName)
lvi.SubItems.Add(ti.Job.ToString)
lvi.SubItems.Add(ti.GetElapsed)
lvi.SubItems.Add(ti.ID)
lvi.Group = myLV.Groups(LVGroups.Running.ToString)
myLV.Items.Add(lvi)
End Sub
' called from dbl click on a running task item
Public Sub StopTask(lvi As ListViewItem)
Dim ti As TaskItem = (From t In col Where t.ID = lvi.SubItems(3).Text).First
' the form doesnt check the status, so we must
If ti.IsActive Then
ti.EndTask()
lvi.Group = myLV.Groups(LVGroups.Completed.ToString)
End If
End Sub
' called from the form timer tick event
Public Sub UpdateDisplay()
Dim ti As TaskItem
' iterate items to get ID of runners
For Each lvi As ListViewItem In myLV.Groups(LVGroups.Running.ToString).Items
' ToDo add error checking
ti = (From t In col Where t.ID = lvi.SubItems(3).Text).First
lvi.SubItems(2).Text = ti.GetElapsed
Next
End Sub
Public Function RunnersCount() As Integer
Return GetActiveList.Count
End Function
Public Function GetCompletedList() As List(Of TaskItem)
' long form
Dim tList As New List(Of TaskItem)
For Each ti As TaskItem In col
If ti.IsActive = False Then
tList.Add(ti)
End If
Next
Return tList
' short form
'Dim list = (From t In col Where t.IsActive = False).ToList
End Function
Public Function GetActiveList() As List(Of TaskItem)
' long form
'Dim tList As New List(Of TaskItem)
'For Each ti As TaskItem In col
' If ti.IsActive Then
' tList.Add(ti)
' End If
'Next
'Return tList
' short form
Dim list = (From t In col Where t.IsActive).ToList
Return list
End Function
End Class
用法:
Public Class Form1
Private myTasks As Tasks
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
myTasks = New Tasks(Me.lvTask)
cboTask.Items.AddRange([Enum].GetNames(GetType(Tasks.TaskJobs)))
End Sub
添加任务:
myTasks.NewTask(cboEmp.Text, CType(cboTask.SelectedIndex, Tasks.TaskJobs))
停止任务:
' called from LV mousedoubleclick, so determine the item
Dim lvi As ListViewItem = lvTask.GetItemAt(e.X, e.Y)
myTasks.StopTask(lvi)
显然,停止任务可能会自动将数据附加到导出文件中。该功能将在任务集合类中,它将在任务从集合中删除之前完成(可选 - 只要您可以从已完成的任务中区分活动,它们就不会伤害那里的任何东西)。
定时器滴答事件:
myTasks.UpdateDisplay()

最后,特别是打开,Option Strict
因为人们将根据项目的输出做出决策。