CODEWITHSUNDEEP
vb.netmultithreadingwinformsloops
user2932566
user2932566

Reputation: 97

Invoking For Loops VB.Net

How do I invoke a for loop in VB.Net?

Example:

    For Each listViewItem As ListViewItem In Me.TaskListView.Items
        Me.ExecuteTask(listViewItem, False)
    Next

So that needs to be invoked, but how do I go about that? I am not sure how. This is inside my background worker handler and causes an InvalidOperationException when inside it. The extra information for the error is: "Cross-thread operation not valid: Control 'TaskListView' accessed from a thread other than the thread it was created on."

The error occurs on this line:

    For Each listViewItem As ListViewItem In Me.TaskListView.Items

Upvotes: 1

Views: 207

Answers (1)

Rustam
Rustam

Reputation: 1776

I overcome problems with threads in winforms using the following subroutine

Public Sub GuiAsync(ByVal frm As Form, ByVal action As Action)
    If action IsNot Nothing Then
        If frm.InvokeRequired Then
            frm.Invoke(action)
        Else
            action()
        End If
    End If
End Sub

I'd use it as follows (in case your code runs in a Form and Me is reference to the Form):

 GuiAsync(Me,
    Sub()
       For Each listViewItem As ListViewItem In Me.TaskListView.Items
           Me.ExecuteTask(listViewItem, False)
       Next
    End Sub)

Upvotes: 1

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