Question

我将值传递给后台工作者和从后台工作者传递值。为此，我使用以下类来存储变量：

Class MyParameters
        Friend _QueryStr As String
        Friend _Value_CreatedDate As Object
        Friend _AccountID As Object
        Friend _Last_Login As Object
        Friend _Motto As Object
        Friend _Bio As Object
        Friend _pFavourite_Game As Object
        Friend _pFacebookLink As Object
        Friend _pInstagram As Object
        Friend _pTwitterLink As Object
        Friend _pTumblerLink As Object
        Friend _pYoutubeLink As Object
        Friend _lblpYoutubeLink As String
        Friend _lblpTumblerLink As String
        Friend _lblpTwitterLink As String
        Friend _lblpInstagram As String
        Friend _lblFacebookLink As String
        Friend _lblpFavourite_Game As String
        Friend _lblBio As String
        Friend _lblMotto As String
        Friend _lblLast_Login As String
        Friend _AccessCode As String
        Friend _TargetUGPoints As String
        Friend _Stream As New MemoryStream()
        Friend _Image As Byte()
        Friend _DoB_Value As Object
        Friend _DoB As Date
        Friend _Years As Integer
        Friend _Months As Integer
        Friend _Cautions_Value As Integer
        Friend _Cautions As Integer
        Friend _Bitmap As New Bitmap(_Stream)
        Friend _Con As New SqlConnection("Data Source =" & My.Settings.ServerIP & ";Initial Catalog=Atlas;Integrated Security=False;User=" & My.Settings.UserName & ";Password=leaders132;")
        Friend _MyCMD As New SqlCommand(_QueryStr, _Con)
    End Class

我在表单加载事件中调用了这样的后台工作程序：

 Private Sub cdb_ProfileViewer_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Loadinglbl.Visible = True
        SpinningProgress1.Visible = True
        MsgBox("Starting MyParamters")
        Dim m As New MyParameters
        MsgBox("My Parameters set to m")
        bw.RunWorkerAsync(m)
    End Sub

但是，该应用程序似乎无法到达后台工作人员。没有冻结或错误，它什么都不做。我仍然像背景工作者一样控制着这个形式，但我认为它甚至没有开始，因为它没有运行任何msgbox。例如，我在代码中添加了Msgbox，以便让我知道代码已到达哪个阶段。如果我将放在 Dim m as New Parameter之前，，而不是之后，它就可以了。

我的背景工作者，请注意我已经省略了我的代码，因为它太过分了：

Private Sub bw_DoWork(ByVal sender As Object, ByVal e As DoWorkEventArgs) Dim m As MyParameters = DirectCast(e.Argument, MyParameters) 'Convert the generic Object back into a MyParameters object Dim worker As BackgroundWorker = CType(sender, BackgroundWorker) e.Result = m 'Do some time-consuming work on this thread end sub

My WorkerCompleted Event，也没有代码：

Private Sub bw_RunWorkerCompleted(ByVal sender As Object, ByVal e As RunWorkerCompletedEventArgs) Dim m As MyParameters = DirectCast(e.Result, MyParameters) 'Convert the generic Object back into a MyParameters object MsgBox("Reached Worker Complete") 'Called when the BackgroundWorker is completed. end sub

我的BW公共类代码：

Private bw As BackgroundWorker = New BackgroundWorker Private Delegate Sub ButtonClick(ByVal sender As Object, ByVal e As EventArgs)

负责BW的Public Sub：

Public Sub New() InitializeComponent() bw.WorkerReportsProgress = False bw.WorkerSupportsCancellation = False AddHandler bw.DoWork, AddressOf bw_DoWork AddHandler bw.RunWorkerCompleted, AddressOf bw_RunWorkerCompleted End Sub

有什么东西可以跳出来吗？正如我所说，我觉得这是Class MyParamters中的一些东西。

Answer 1

不幸的是，Load（）事件吞噬了您的异常。将该代码移动到Constructor或Shown（）事件，问题变得明显：

    Friend _Bitmap As New Bitmap(_Stream)

您无法从空流中创建位图...

要重现的最少代码：

Public Class MyParameters
    Friend _Stream As New MemoryStream()
    Friend _Bitmap As New Bitmap(_Stream)
End Class

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim M As New MyParameters
End Sub

VB MyParameters类似乎停止了

1 个答案: