1

我需要一个适合我的 Visual Basic 中的等待命令。

我知道：

Declare Sub Sleep Lib "kernel32.dll" (ByVal milliseconds As Long)
sleep 5000

但这会使程序无响应。

System.Threading.Thread.Sleep(5000) 'The window doesn't load until the timing is over (useless)

我的代码：

Imports Microsoft.Win32 'To check if is 64Bit or 32Bit

Public Class Loading
  Private Sub Loading_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    If Registry.LocalMachine.OpenSubKey("Hardware\Description\System\CentralProcessor\0").GetValue("Identifier").ToString.Contains("x86") Then
      My.Settings.Is64 = False
    Else
      My.Settings.Is64 = True
    End If

    'I need command here

    If My.Settings.Is64 = True Then
      Form64.Show()
      Me.Close()
    Else
      MsgBox("No version developed for 32-bit computers.")
      End
    End If
  End Sub
End Class

错误：

@Idle_Mind

1. function 'OnInitialize' cannot be declared 'Overrides' because it does not override a function in a base class.
2.  'MinimumSplashScreenDisplayTime' is not a member of 'App.Loading.MyApplication'.
    3.  'OnInitialize' is not a member of 'Object'.
4

5 回答 5

7

从评论：

在此处输入图像描述

进入项目属性并将您的主窗体保留为启动窗体。将启动屏幕表单设置为底部的启动屏幕条目。现在单击右侧的“查看应用程序事件”按钮并覆盖OnIntialize，以便您可以像这样设置MinimumSplashScreenDisplayTime()：

Namespace My

    ' The following events are available for MyApplication:
    ' 
    ' Startup: Raised when the application starts, before the startup form is created.
    ' Shutdown: Raised after all application forms are closed.  This event is not raised if the application terminates abnormally.
    ' UnhandledException: Raised if the application encounters an unhandled exception.
    ' StartupNextInstance: Raised when launching a single-instance application and the application is already active. 
    ' NetworkAvailabilityChanged: Raised when the network connection is connected or disconnected.
    Partial Friend Class MyApplication

        Protected Overrides Function OnInitialize(ByVal commandLineArgs As System.Collections.ObjectModel.ReadOnlyCollection(Of String)) As Boolean
            ' Set the display time to 5000 milliseconds (5 seconds). 
            Me.MinimumSplashScreenDisplayTime = 5000
            Return MyBase.OnInitialize(commandLineArgs)
        End Function

    End Class


End Namespace
于 2013-07-12T14:31:07.173 回答
3

如果您想在 5 秒后执行其余代码，为什么不创建一个单独的线程/任务，它会等待 5 秒，然后通过对主线程的回调触发其余代码运行？这种方法不会挂起您的 UI。

编辑：如果你想要一个启动画面，放下一个 Timer 控件，将间隔设置为 5 秒，然后在 Tick 事件处理程序中运行其余代码。

假设您已经设置了 Timer，请将您的加载代码移动到Timer1_Tick处理程序中：

Public Class Loading
  Private Sub Timer1_Tick(sender As System.Object, e As System.EventArgs) Handles Timer1.Tick
    'part 1
    If Registry.LocalMachine.OpenSubKey("Hardware\Description\System\CentralProcessor\0").GetValue("Identifier").ToString.Contains("x86") Then
      My.Settings.Is64 = False
    Else
      My.Settings.Is64 = True
    End If

    'part 2
    If My.Settings.Is64 = True Then
      Form64.Show()
      Me.Close()
    Else
      MsgBox("No version developed for 32-bit computers.")
      End
    End If
  End Sub
End Class

或将第 1 部分留在 中Load，将第 2 部分移入Tick。对于语义，我更喜欢这个选项。

也不要忘记设置Timer.Enabled = True。

于 2013-07-12T14:12:20.730 回答
2

如果你想要一个地方来取消应用程序，你可以使用Application.Startup事件并e.Cancel = True从那里设置。完成后，主窗体甚至不会出现；应用程序将简单地退出。这可能看起来像：

Namespace My

    ' The following events are available for MyApplication:
    ' 
    ' Startup: Raised when the application starts, before the startup form is created.
    ' Shutdown: Raised after all application forms are closed.  This event is not raised if the application terminates abnormally.
    ' UnhandledException: Raised if the application encounters an unhandled exception.
    ' StartupNextInstance: Raised when launching a single-instance application and the application is already active. 
    ' NetworkAvailabilityChanged: Raised when the network connection is connected or disconnected.
    Partial Friend Class MyApplication

        Private Sub MyApplication_Startup(sender As Object, e As Microsoft.VisualBasic.ApplicationServices.StartupEventArgs) Handles Me.Startup
            If someCondition Then
                MessageBox.Show("oops")
                e.Cancel = True ' <-- main form will NOT show, app will simply exit
            End If
        End Sub

    End Class


End Namespace
于 2013-07-12T15:03:03.223 回答
1

这样做：

    For i As Integer = 1 To 500
        System.Threading.Thread.Sleep(10)
        System.Windows.Forms.Application.DoEvents()
    Next

编辑：小心 DoEvents；如果用户单击某些内容或处理不应该处理的事件，则可能会导致问题。见 http://www.codinghorror.com/blog/2004/12/is-doevents-evil.html

于 2013-07-12T13:25:35.853 回答
0

由于睡觉和忙着等待通常是不受欢迎的，你可以做一些事情AutoResetEvent：

Private ReadOnly _resetEvent As AutoResetEvent = New AutoResetEvent(False)

Sub Pause(ByVal milliseconds As Long)
    Dim waitInterval As TimeSpan = TimeSpan.FromMilliseconds(milliseconds)
    While Not _resetEvent.WaitOne(waitInterval)
         ' Waiting!
    End While
End Sub

不建议这样做，但这里有一个使用System.Diagnostics.Stopwatch类的示例：

Sub Pause(ByVal milliseconds As Long)
    If milliseconds <= 0 Then Return
    Dim sw As New Stopwatch()
    sw.Start()
    Dim i As Long = 0
    Do
        If i Mod 50000 = 0 Then ' Check the timer every 50,000th iteration
            sw.Stop()
            If sw.ElapsedMilliseconds >= milliseconds Then
                Exit Do
            Else
                sw.Start()
            End If
        End If
        i += 1
    Loop
End Sub

然后在需要暂停的地方，调用这个Pause()方法：

Pause(5000) ' Pause for 5 seconds
于 2013-07-12T13:23:17.113 回答