vb.net threading.thread传递变量的地址 [英] vb.net threading.thread addressof passing variables

问题描述

我正在尝试将某些状态从共享子项中的IP呼叫传递到表单上的标签.

I am trying to pass some status from a IP call in a shared sub to a label on my form.

这是我正在使用的当前代码:

This is the current code that i am using:

Class Server
    <STAThread()> Public Shared Sub Main()
        Dim aTcpMessaging As IMessagingSystemFactory = New TcpMessagingSystemFactory()
        Dim anInputChannel As IInputChannel = aTcpMessaging.CreateInputChannel(theIPforLocal & ":" & thePort)
        Dim aStringMessagesFactory As IStringMessagesFactory = New StringMessagesFactory()
        Dim aStringMessageReceiver As IStringMessageReceiver = aStringMessagesFactory.CreateStringMessageReceiver()
        AddHandler aStringMessageReceiver.MessageReceived, AddressOf StringMessageReceived

        aStringMessageReceiver.AttachInputChannel(anInputChannel)
    End Sub

    Private Shared Sub StringMessageReceived(ByVal sender As Object, ByVal e As StringMessageEventArgs)
        LANResponse = Convert.ToString(e.Message)
        Dim lanSent As String() = Nothing
        Dim sep(3) As Char
        Dim s As String = ""

        sep(0) = "~"
        'sep(1) = ","
        lanSent = LANResponse.Split(sep, 2)

        Dim a As New Threading.Thread(AddressOf getStatus)

        a.SetApartmentState(Threading.ApartmentState.STA)
        a.Start(Trim(lanSent(0)) & Trim(lanSent(1)))
  End Sub
End Class

Private Shared Sub getStatus(ByVal data As Object)
    lblStatus.text = ("Static: " & data)
End Sub

它给我的错误在行上 lblStatus.text =("Static:"& data)

错误1如果没有该类的显式实例，则无法从共享方法或共享成员初始化程序中引用该类的实例成员.

Error 1 Cannot refer to an instance member of a class from within a shared method or shared member initializer without an explicit instance of the class.

任何帮助都会很棒！

大卫

更新

添加后:

Private Sub getStatus(ByVal data As Object)
    If InvokeRequired Then
        Invoke(New Action(Of Object)(AddressOf getStatus), data)
    Else
        lblStatus.Text = ("Static: " & data)
    End If
End Sub

我没有一行得到此错误将新的Threading.Thread(AddressOf getStatus)昏暗

I get this error no one line Dim a As New Threading.Thread(AddressOf getStatus)

错误1重载解析失败，因为无法使用以下参数调用可访问的新建": 'Public Sub New(以System.Threading.ParameterizedThreadStart开头):对非共享成员的引用需要一个对象引用. 'Public Sub New(从System.Threading.ThreadStart开始):方法'Private Sub getStatus(作为对象的数据)'不具有与委托'Delegate Sub ThreadStart()'兼容的签名.

Error 1 Overload resolution failed because no accessible 'New' can be called with these arguments: 'Public Sub New(start As System.Threading.ParameterizedThreadStart)': Reference to a non-shared member requires an object reference. 'Public Sub New(start As System.Threading.ThreadStart)': Method 'Private Sub getStatus(data As Object)' does not have a signature compatible with delegate 'Delegate Sub ThreadStart()'.

推荐答案

我注意到您正在尝试使用Shared成员来完成这项工作.这可能是有问题的，原因如下:

I've noticed you're trying to make this work using Shared members. That may be problematic for the following reasons:

(1)在没有Shared的情况下，在后台创建了一个引用变量，该变量称为Me.通过Me，您可以进入lblStatus，例如Me.lblStatus，实际上不必一定要放入Me，一个人可以自己指定lblStatus.但是，即使单独使用Me，它也隐含在其中，并且仍在使用.

(1) Without the Shared, behind the scenes a reference variable is created, and it is called Me. Via Me you can get to lblStatus, such as Me.lblStatus, and actually one doesn't necessarily need to put in the Me, one could specify lblStatus by itself. But, even by itself, the Me is implied there, and is still used.

(2)对于Shared，没有Me.没有Me，编译器就没有lblStatus实例可以识别-因此出错. 您将需要找到某种方式来传递对您的表格的引用，以从中访问lblStatus.但是，我需要警告您，直接从除主线程之外的其他线程更新Label或其他用户界面类被认为是不好的-这是因为WinForms并不是线程安全的.从.NET Framework 2开始，如果尝试尝试将收到错误消息(尽管有可能自行退出此错误，但后果自负).

(2) With the Shared, there is no Me. Without the Me, there is no lblStatus instance for the compiler to identify - hence the error. You will need to find some way to pass in a reference to your Form from which to access lblStatus. I need to warn you, though, that updating a Label or other user interface class directly from a thread other than the main thread is regarded as something bad - this is because WinForms is not thread-safe. Beginning with .NET Framework 2, you'll get an error if you try (although it is possible to opt-out of this error, at your own peril).

这些用于C#，但可能会为您提供一些有关如何进行的想法:

These are for C#, but it may give you some ideas on how to proceed:

如何从C#中的另一个线程更新GUI?

http://www.codeproject.com/Articles/23517/How-to-Properly-Handle-Cross-thread-Events-and-Upd

所以第一步是使getStatus不是共享成员-这将带回Me.

So step one is to make getStatus not a shared member - that will bring back the Me.

第二步是将getStatus重新设计为线程安全的形式，以将文本获取到Label中，例如:

Step two is to redesign getStatus into a thread-safe form for getting the text into the Label, such as:

Private Sub getStatus(ByVal data As Object)
    If InvokeRequired Then
        Invoke(New Action(Of Object)(AddressOf getStatus), data)
    Else
        lblStatus.Text = ("Static: " & data)
    End If
End Sub

第三步是找到某种方法来获取对您的Form的引用到Server中-可能是通过共享的ArrayList?还是只是共享引用了Form?

Step three is to find some way to get a reference to your Form into Server - may be via a shared ArrayList? Or just some shared reference to Form?

第四步是对StringMessageReceived的重新设计，以使AddressOf部分现在采用AddressOf refToMyForm.getStatus的形式.

Step four is a redesign of StringMessageReceived so that the AddressOf portion is now in the form of AddressOf refToMyForm.getStatus.

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