自定义类事件触发后，表单不会更新 [英] Form is not updating, after custom class event is fired
问题描述
我遇到一个问题，即我的主要表单不更新，即使我看到事件的火了。让我解释一下这个情况，并分享我的一些代码，我相信这将是可怕的，因为我是一个业余。
我创建了一个类来接受设置用于在后台运行进程。我在该类中添加了一些自定义事件，所以我可以在我的形式而不是一个计时器。
我把休息一下，我看到他们一开始安装就会被启动。
我看看数据，它遇到，没有异常抛出。
最初我认为这是因为datagridview有一些延迟问题。我设置为双缓冲通过一些技巧，我发现，但它没有关系。在数据显示在数据网格之前，仍然有大约10秒的延迟。
我想了一下，决定我真的不需要datagridview，与多行文本框，但它没有什么区别。仍然需要10秒或更长时间才能显示表单/文字框的更新。
我已经在下面加入了部分代码。
公共共享WithEvents np As NewProcess
Private Sub Form1_Load（ByVal sender As Object，ByVal e As System.EventArgs）Handles Me.Load
Try
np = New NewProcess
AddHandler np.InstallFinished，AddressOf np_InstallFinished
AddHandler np.InstallStarted，AddressOf np_InstallStarted
Catch ex As Exception
结束尝试
End Sub
保护子np_InstallFinished（ByVal描述As String，ByVal ExitCode As Integer）
InstallInProcess = False
如果不是说明=没有然后
如果不是ExitCode =没有然后
AddLog（String.Format（{0}（{1}）。，说明，ExitCode的完成安装））
Else
AddLog（String.Format（{0} ，Description））
End If
End If
RefreshButtons（）
UpdateListofApps（）
np.Dispose（）
End Sub
受保护子np_InstallStarted描述As String）
InstallInProcess = True
如果不是描述=没有然后AddLog（String.Format（开始安装{0}。，说明））
End Sub
public class NewProcess
Dim ProcessName As String
Dim ProcessVisibile As Boolean
Dim Arguments As String
Dim WaitforExit As Boolean
Dim说明As String
Dim ShellExecute As布尔
Dim EC As Integer = Nothing'退出代码
私有IsBusy作为布尔值=无
Dim th As Threading.Thread
公共事件InstallFinished（ByVal描述As String ，ByVal ExitCode As Integer）
公共事件InstallStarted（ByVal描述As String）
公共函数Busy（）As Boolean
如果IsBusy = Nothing then Return False
返回IsBusy
结束函数
公共函数ExitCode（）As Integer
返回EC
结束函数
公共函数ProcessDescription ）As String
返回说明
结束函数
'''< summary>
'''启动新的多线程进程。
'''< / summary>
'''< param name =path>要运行的文件的路径< / param>
'''< param name =Visible>应用程序是否可见？< / param&
'''< param name =Arg>参数< / param>
'''< param name =WaitforExit>等待应用程序退出？< / param>
'''< param name =Description>描述将显示在日志中< / param>
'''< remarks>开始一个新的多线程进程。< / remarks>
Public Sub StartProcess（ByVal path As String，ByVal Visible As Boolean，可选ByVal Arg As String = Nothing，可选ByVal WaitforExit As Boolean = False，可选ByVal描述As String = Nothing）
尝试
Me.ProcessName = path
Me.ProcessVisibile = Visible
如果Arguments = Nothing然后Me.Arguments = Arg
Me.Description =说明
Me.WaitforExit = WaitforExit
如果IsBusy和WaitforExit然后
MessageBox.Show（另一个安装已经在进行中，请等待上一次安装完成。，警告，MessageBoxButtons.OK，MessageBoxIcon。警告）
退出子
结束如果
如果不是fn_FileExists（ProcessName）然后
MessageBox.Show（找不到文件& ProcessName&。 ，Could not start process because file is missing。，MessageBoxButtons.OK，MessageBoxIcon.Error）
退出Sub
结束如果
th = New Threading.Thread（AddressOf NewThread）
使用th
.IsBackground = True
如果不是说明没有则说明.Name =说明
.Start（）
End With
Catch ex As Exception
结束尝试
结束子
Private Sub NewThread（）
Dim p作为进程
尝试
p =新进程
使用p
.EnableRaisingEvents = True
.StartInfo.Arguments = Arguments
.StartInfo.FileName = ProcessName
.StartInfo.CreateNoWindow = ProcessVisibile
使用
结束
如果ProcessVisibile则
p.StartInfo.WindowStyle = ProcessWindowStyle.Normal
Else
p.StartInfo。 WindowStyle = ProcessWindowStyle.Hidden
结束如果
p.Start（）
IsBusy = True
RaiseEvent InstallStarted（说明）
如果WaitforExit然后
Do While p.HasExited = False
Threading.Thread.Sleep（500）
Loop
IsBusy = False
RaiseEvent InstallFinished（说明，p.ExitCode）
End If
EC = p.ExitCode
Catch ex As Exception
结束尝试
结束子
Public Sub Dispose（）
ProcessName = Nothing
ProcessVisibile = Nothing
Arguments = Nothing
WaitforExit = Nothing
说明= Nothing
EC =没有
InstallInProcess =没有
th.Join（）
MemoryManagement.FlushMemory（）
结束子
结束类
Sub AddLog（ByVal s As String）
Try
s = String.Format（[{0}] {1}，TimeOfDay.ToShortTimeString，s）
Form1.tbLogs.AppendText ; vbCrLf）
使用st As New StreamWriter（LogFilePath，True）
st.WriteLine（s）
st.Flush（）
结束使用
Catch ex As Exception
结束尝试
结束子
？我完全失去了。
我试过添加application.doevents，me.refresh和很多其他事情：（
解决方案
Form1.tbLogs.AppendText（s& vbCrLf）/ pre>
标准VB.NET陷阱Form1是一个类名，而不是对表单的引用不幸的是，VB.NET从VB6中实现了一个时间错误当你使用线程时，它会崩溃，你会得到另一个自动创建的表单对象，因为它的Show（）方法从未被调用而不可见。线程不是一个消息循环。
你需要传递一个引用到用户正在查看的工作类的实际表单对象。我在Form1代码中，你还必须使用Control.Invoke，因为它是不合法的更新控件从另一个线程。我建议你启动一个事件，而Form1可以订阅，所以你的工作类是' t感染UI的实现细节。
I'm having an issue where my main form isn't updating even though I see the event fire off. Let me explain the situation and share some of my code which I'm sure will be horrible since I'm an amateur.
I created a class to take in the settings for running a process in the background. I add some custom events in that class so I could use that in my form instead of a timer.
I put a break on the two subs for that handle those events and I see them get kicked off as soon as an install starts.
I look at the data and it's coming across and no exceptions are thrown.
At first I thought it was because the datagridview had some latency issues. I set that to be double buffered through some tricks I found but it didn't matter. There was still a roughly 10 second delay before the data showed up in the datagrid.
I thought about it and decided I really didn't need a datagridview and replaced the control with a multiline textbox, but it didn't make a difference. It's still taking 10 seconds or longer to show updates to the form/textbox.
I've included some of my code below.
Public Shared WithEvents np As NewProcess
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Try np = New NewProcess AddHandler np.InstallFinished, AddressOf np_InstallFinished AddHandler np.InstallStarted, AddressOf np_InstallStarted Catch ex As Exception End Try End Sub
Protected Sub np_InstallFinished(ByVal Description As String, ByVal ExitCode As Integer) InstallInProcess = False If Not Description = Nothing Then If Not ExitCode = Nothing Then AddLog(String.Format("Completed install of {0} ({1}).", Description, ExitCode)) Else AddLog(String.Format("Completed install of {0}.", Description)) End If End If RefreshButtons() UpdateListofApps() np.Dispose() End Sub
Protected Sub np_InstallStarted(ByVal Description As String) InstallInProcess = True If Not Description = Nothing Then AddLog(String.Format("Started the install of {0}.", Description)) End Sub
Public Class NewProcess Dim ProcessName As String Dim ProcessVisibile As Boolean Dim Arguments As String Dim WaitforExit As Boolean Dim Description As String Dim ShellExecute As Boolean Dim EC As Integer = Nothing 'Exit Code Private IsBusy As Boolean = Nothing Dim th As Threading.Thread Public Event InstallFinished(ByVal Description As String, ByVal ExitCode As Integer) Public Event InstallStarted(ByVal Description As String) Public Function Busy() As Boolean If IsBusy = Nothing Then Return False Return IsBusy End Function Public Function ExitCode() As Integer Return EC End Function Public Function ProcessDescription() As String Return Description End Function ''' <summary> ''' Starts a new multithreaded process. ''' </summary> ''' <param name="path">Path of the File to run</param> ''' <param name="Visible">Should application be visible?</param> ''' <param name="Arg">Arguments</param> ''' <param name="WaitforExit">Wait for application to exit?</param> ''' <param name="Description">Description that will show up in logs</param> ''' <remarks>Starts a new multithreaded process.</remarks> Public Sub StartProcess(ByVal path As String, ByVal Visible As Boolean, Optional ByVal Arg As String = Nothing, Optional ByVal WaitforExit As Boolean = False, Optional ByVal Description As String = Nothing) Try Me.ProcessName = path Me.ProcessVisibile = Visible If Arguments = Nothing Then Me.Arguments = Arg Me.Description = Description Me.WaitforExit = WaitforExit If IsBusy And WaitforExit Then MessageBox.Show("Another install is already in process, please wait for previous install to finish.", "Warning", MessageBoxButtons.OK, MessageBoxIcon.Warning) Exit Sub End If If Not fn_FileExists(ProcessName) Then MessageBox.Show("Could not find file " & ProcessName & ".", "Could not start process because file is missing.", MessageBoxButtons.OK, MessageBoxIcon.Error) Exit Sub End If th = New Threading.Thread(AddressOf NewThread) With th .IsBackground = True If Not Description Is Nothing Then .Name = Description .Start() End With Catch ex As Exception End Try End Sub Private Sub NewThread() Dim p As Process Try p = New Process With p .EnableRaisingEvents = True .StartInfo.Arguments = Arguments .StartInfo.FileName = ProcessName .StartInfo.CreateNoWindow = ProcessVisibile End With If ProcessVisibile Then p.StartInfo.WindowStyle = ProcessWindowStyle.Normal Else p.StartInfo.WindowStyle = ProcessWindowStyle.Hidden End If p.Start() IsBusy = True RaiseEvent InstallStarted(Description) If WaitforExit Then Do While p.HasExited = False Threading.Thread.Sleep(500) Loop IsBusy = False RaiseEvent InstallFinished(Description, p.ExitCode) End If EC = p.ExitCode Catch ex As Exception End Try End Sub Public Sub Dispose() ProcessName = Nothing ProcessVisibile = Nothing Arguments = Nothing WaitforExit = Nothing Description = Nothing EC = Nothing InstallInProcess = Nothing th.Join() MemoryManagement.FlushMemory() End Sub End Class
Sub AddLog(ByVal s As String) Try s = String.Format("[{0}] {1}", TimeOfDay.ToShortTimeString, s) Form1.tbLogs.AppendText(s & vbCrLf) Using st As New StreamWriter(LogFilePath, True) st.WriteLine(s) st.Flush() End Using Catch ex As Exception End Try End SubAny idea's? I'm at a complete loss.
I've tried adding application.doevents, me.refresh and quite a few other things :(
解决方案Form1.tbLogs.AppendText(s & vbCrLf)Standard VB.NET trap. Form1 is a class name, not a reference to the form. Unfortunately, VB.NET implemented an anachronism from VB6 where that was legal. It however falls apart when you use threads. You'll get another form object automatically created, one that isn't visible because its Show() method was never called. Otherwise dead as a doornail since the thread is not pumping a message loop.
You'll need to pass a reference to the actual form object that the user is looking at to the worker class. The value of Me in the Form1 code. You will also have to use Control.Invoke since it isn't legal to update controls from another thread. I recommend you fire an event instead, one that Form1 can subscribe to, so that your worker class isn't infected with implementation details of the UI.
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