Question

我试图以线程安全的方式将一个子项添加到listview。

在单线程应用程序中，它的工作原理如下：

    For i As Integer = 0 to lvMembers.Items.Count - 1
    Dim lv As ListViewItem = lvMembers.Items(i)
    Dim str As String = lv.Text.ToString
    If str.Contains("value")
    lv.SubItems.Add("OK")
    lv.SubItems(0).ForeColor = Color.Green

    Else
    lv.SubItems.Add("FAILED")
    lv.SubItems(0).ForeColor = Color.Red

    End If
    Next

但是，如果在另一个线程中运行，则会导致交叉线程错误。

我已经查看了使用Invoke的委托子的示例，但是我看到的所有示例都涉及更新对象的text属性，而我无法理解如何应用该概念来实际向listview添加子项

非常感谢任何帮助。

Answer 1

这是一个我一遍又一遍地用于自己用途的例子。它支持传递变量。此示例中的列表视图包含1个项目和2个子项目（site，group，pagerank），因此请根据自己的需要进行修改：

代表：

Private Delegate Sub ListViewAddItem_delegate(ByVal name As String, ByVal group As String, ByVal pagerank As String)
Private Sub ListViewAddItem(ByVal name As String, ByVal group As String, ByVal pagerank As String)
    If Me.ListView1.InvokeRequired Then
        Dim d As New ListViewAddItem_delegate(AddressOf ListViewAddItem)
        Me.ListView1.BeginInvoke(d, {name, group, pagerank})
    Else
        Dim lvi As New ListViewItem(name)
        lvi.SubItems.Add(group)
        lvi.SubItems.Add(pagerank)
        ListView1.Items.AddRange(New ListViewItem() {lvi})
        ListView1.Update()
    End If
End Sub

如何称呼它：

Dim Name as string = "Test"
Dim Group As String = "TestGroup"
Dim PR As String = "10"
ListViewAddItem(Name, Group, PR)

我添加了“dim xxx as string”这些东西只是为了表明在调用ListViewAddItem（）

时Name Group PR是字符串

我注意到没有选择任何答案。帮我们一个忙，选择一个！谢谢！

Answer 2

将新ListViewItem添加到ListView的线程安全简化方法：

<?xml version='1.0' encoding='utf-8' standalone='yes' ?>
<map>
<string name="COUNT_KEY">235</string>
</map>

Answer 3

Private delegate sub deladdtolist

Private sub addtolist
  If InvokeRequired Then
    del.Invoke( new deladdtolist(AddressOf addtolist))
  else
    For i As Integer = 0 to lvMembers.Items.Count - 1
    Dim lv As ListViewItem = lvMembers.Items(i)
    Dim str As String = lv.Text.ToString
    If str.Contains("value")
    lv.SubItems.Add("OK")
    lv.SubItems(0).ForeColor = Color.Green

    Else
    lv.SubItems.Add("FAILED")
    lv.SubItems(0).ForeColor = Color.Red

    End If
    Next
  End If 
End Sub

Answer 4

一个简单的例子

Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, _
                           ByVal e As System.EventArgs) Handles MyBase.Load

        'sample data for the ListView
        Dim ipsumA() As String = New String() {"Lorem", "ipsum", "dolor", "sit", _
                                               "amet", "consectetur", "adipisicing", _
                                               "elit", "sed", "do", "eiusmod", _
                                               "tempor", "incididunt", "ut", "labore", _
                                               "et", "dolore", "magna", "aliqua", "Ut", _
                                               "enim", "ad", "minim", "veniam", "quis", _
                                               "nostrud", "exercitation", "ullamco", _
                                               "laboris", "nisi", "ut", "aliquip", "ex", _
                                               "ea", "commodo", "consequat", "Duis", "aute", _
                                               "irure", "dolor", "in", "reprehenderit", "in", _
                                               "voluptate", "velit", "esse", "cillum", "dolore", _
                                               "eu", "fugiat", "nulla", "pariatur", "Excepteur", _
                                               "sint", "occaecat", "cupidatat", "non", "proident", _
                                               "sunt", "in", "culpa", "qui", "officia", "deserunt", _
                                               "mollit", "anim", "id", "est", "laborum"}

        Dim lvi As New List(Of ListViewItem)

        For Each s As String In ipsumA
            Dim nLVI As New ListViewItem(s)
            lvi.Add(nLVI)
        Next

        ListView1.Items.AddRange(lvi.ToArray)

        'colorize from another thread
        Dim t As New Threading.Thread(AddressOf thrd)
        t.Start()

    End Sub

    Private Sub thrd()
        If ListView1.InvokeRequired Then
            ListView1.BeginInvoke(New MethodInvoker(AddressOf thrd))
        Else
            For i As Integer = 0 To ListView1.Items.Count - 1
                Dim lv As ListViewItem = ListView1.Items(i)
                Dim str As String = lv.Text.ToString
                If str.ToLower.Contains("ut") Then
                    lv.SubItems.Add("OK")
                    lv.SubItems(0).ForeColor = Color.Green

                Else
                    lv.SubItems.Add("FAILED")
                    lv.SubItems(0).ForeColor = Color.Red
                End If
            Next
        End If
    End Sub
End Class

VB.net线程安全方法添加listview子项？

4 个答案: