-1

在开始之前，我知道这个问题已经有了很多答案，但让我解释一下发生了什么。

我基本上想将一些文本附加到 RichTextBox 元素，它对我来说就像一个记录器来通知用户来自文件处理的每个操作，但是文本通过 for 循环附加到 RichTextBox，如果我在同一类“Form1.vb”UI 冻结，直到循环完成。

我决定在一个单独的线程中运行循环以避免 UI 冻结，这就是我的问题开始的地方。

Form1.vb

Imports System.Threading


Public Class Form1

    Dim myThread As Thread

    Private Sub appendMyText()
        ' Cross-thread operation not valid: Control txtLogger accessed from a thread other than the thread it was created on.
        txtLogger.AppendText("Hello World" & vbNewLine)
    End Sub

    Private Sub btnTest_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnTest.Click
        myThread = New Thread(New ThreadStart(AddressOf appendMyText))
        myThread.Start()
    End Sub

End Class

我无法从另一个线程访问 txtLogger 元素，所以我尝试了 MSDN 示例 https://msdn.microsoft.com/en-us/library/ms171728(v=vs.110).aspx?cs-save-lang =1&cs-lang=vb#code-snippet-2

它向我展示了如何使用委托访问进行线程安全调用的元素。

所以我编辑的代码是

Form1.vb

Imports System.Threading

Public Class Form1

    Dim myThread As Thread
    Delegate Sub AppendMyText(ByVal text As String)

    ' Add the text to RichTextBox
    Private Sub addText(ByVal txt As String)
        If txtLogger.InvokeRequired Then
            Dim myDelegate = New AppendMyText(AddressOf addText)
            Me.Invoke(myDelegate, {txt})
        Else
            txtLogger.AppendText(txt)
        End If
    End Sub

    ' Call the method that add text to RichTextBox
    Private Sub threadSafe()
        Me.addText("Hello World" & vbNewLine)
    End Sub

    Private Sub btnTest_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnTest.Click
        myThread = New Thread(New ThreadStart(AddressOf threadSafe))
        myThread.Start()
    End Sub

End Class

代码确实是这样工作的，文本附加到 RichTextBox，但所有代码都在同一个类 Form1.vb 中

在我原来的项目中，for循环是在另一个类中执行的，在这里我将它命名为“Class1.vb”。

那是代码示例

类1.vb

Public Class Class1

    Public Sub count()
        Dim i As Integer

        For i = 0 To 100
            ' this method will be executed by thread "myThread"
            ' how to append text to txtLogger from here?
            Debug.WriteLine("Index: {0}", i)
        Next
    End Sub

End Class
4

1 回答 1

2

将表单引用传递给类

以你的形式

Dim MyClass as Class1
MyClass = New Class1(Me)

在你的班级

Public Class Class1

     Private Parent_From as Form1
     Public Sub New(Parent as Form1)
           Parent_From = Form
     End sub
     Public Sub count()
        Dim i As Integer
        For i = 0 To 100
            ' this method will be executed by thread "myThread"
            Parent_Form.addTExt("Whatever")
            Debug.WriteLine("Index: {0}", i)
        Next
    End Sub
End CLass
于 2017-02-21T18:20:27.347 回答