vb.net Visual Basic 2010 检查表单加载时文件是否存在
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Visual basic 2010 Check if file exists on form load
提问by user1955680
I would like my Visual Basic app to run a splash screen with a progress bar and after that to check if file exists, but I have a problem since as soon as I start and the splash screen shows up the file checker fires up, but I would like it to check when form1loads and not splash screen. Here is my code, I could use an advice:
我希望我的 Visual Basic 应用程序运行带有进度条的启动画面，然后检查文件是否存在，但是我遇到了一个问题，因为一旦我启动并且启动画面显示文件检查器就会启动，但是我希望它检查何时form1加载而不是启动屏幕。这是我的代码，我可以使用一个建议：
Splash screen :
启动画面：
Public NotInheritable Class SplashScreen1
'TODO: This form can easily be set as the splash screen for the application by going to the "Application" tab
' of the Project Designer ("Properties" under the "Project" menu).
Private Sub Splashscreen1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim Dte As DateTime = DateTime.Now
Label2.Text = FormatDateTime(Dte, DateFormat.LongDate)
Timer1.Start()
Timer2.Start()
End Sub
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
If ProgressBar1.Value = ProgressBar1.Maximum Then
Form1.Show()
Me.Close()
End If
End Sub
Private Sub Timer2_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer2.Tick
ProgressBar1.PerformStep()
End Sub
End Class
Form 1 :
表格一：
Imports System.Net
Imports System.IO
Public Class Form1
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If My.Computer.FileSystem.FileExists(Application.StartupPath & "/read me.txt") Then
MsgBox("file found")
Else
MsgBox("not found")
End If
End Sub
End Class
回答by Jason Tyler
Try moving your Form1 code from the Load event to the Shown event. Load is run before the form is visible to the user, which is not what you want from what I understand.
尝试将您的 Form1 代码从 Load 事件移动到 Shown 事件。Load 在表单对用户可见之前运行，根据我的理解，这不是您想要的。
回答by Donny McCoy
Your timer1_tick event is causing this issue. Timer1 is enabled at splashscreen load and depending on the timer_interval it may never display before form1 loads. Do you want the user to see something during this time?
您的 timer1_tick 事件导致了此问题。Timer1 在启动画面加载时启用，并且根据 timer_interval 它可能永远不会在 form1 加载之前显示。你想让用户在这段时间内看到什么吗？
The progress bar implies an action or set of actions is taking place. What do you have taking place that requires the progress bar? If you want the illusion of things happening, make sure you timer1 interval is greater than your timer2 interval since timer1 controls how long the splashscreen is visible before form1 is loaded.
进度条暗示正在发生一个动作或一组动作。你有什么事情需要进度条？如果您想要事情发生的错觉，请确保 timer1 间隔大于 timer2 间隔，因为 timer1 控制在加载 form1 之前启动画面可见的时间。
回答by s3ktonic
If ProgressBar1.Value = ProgressBar1.Maximum Then
Form1.Show()
Me.Close()
End If
change to:
改成：
If ProgressBar1.Value = ProgressBar1.Maximum Then
Form1.Visible = True
Me.Visible = False
End If
