WPF vb.net 线程更新UI

最新推荐文章于 2024-05-04 17:14:16 发布

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最新推荐文章于 2024-05-04 17:14:16 发布 · 888 阅读

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本文详细探讨了在WPF应用程序中，如何使用VB.NET进行多线程操作并安全地更新用户界面（UI）。内容涵盖了解决UI线程同步问题的策略，如Dispatcher对象的使用，以及在后台线程中更新UI组件的技巧。

    '定义委托
    Delegate Sub Gxdjs(ByVal data As String)
    Private Sub UpdateStatus(ByVal n As String)
        Dispatcher.Invoke(New Gxdjs(AddressOf Cdjs), n) '用Invoke跨线程更新UI
    End Sub
    Private Sub Cdjs(ByVal data As String) '这里要和委托定义时的参数保持一致
        lb_Status.Text = data
    End Sub

'引用
Dim Msg As String = "正在下载" + filename + "......"
UpdateStatus(Msg)
APP.DoEvents()

Imports System.Windows.Threading

Partial Class APP
    Inherits Application
    Private Shared exitFrameCallback As New DispatcherOperationCallback(AddressOf ExitFrame)
    Public Shared Sub DoEvents()

        Dim nestedFrame = New DispatcherFrame()
        Dim exitOperation = Dispatcher.CurrentDispatcher.BeginInvoke(DispatcherPriority.Background, exitFrameCallback, nestedFrame)
        Dispatcher.PushFrame(nestedFrame)

        If exitOperation.Status <> DispatcherOperationStatus.Completed Then
            exitOp