VB.NET如果ElseIf發生在計時器

-1

我試圖運行3個計時器使用一個按鈕，每次點擊1計時器將運行。它在第二次計時器中運行平穩，但在第三次點擊第三次計時器沒有運行。任何人都可以幫我解決這個問題嗎？VB.NET如果ElseIf發生在計時器

這裏是我的代碼

Public Class Form1 

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click 

     If Timer1.Enabled = False Then 
      Timer1.Start() 
     ElseIf Timer1.Enabled = True Then 
      Timer2.Start() 
     ElseIf Timer1.Enabled = True And 
      Timer2.Enabled = true Then 
      Timer3.Start() 

     End If 

    End Sub 

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick 
     Label1.Text = Label1.Text + 1 
     If Label1.Text = 60 Then 
      Label1.Text = 0 
      Label2.Text += 1 
     ElseIf Label2.Text = 60 Then 
      Label2.Text = 0 
      Label3.Text += 1 
     End If 

    End Sub 

    Private Sub Timer2_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer2.Tick 
     Label6.Text = Label6.Text + 1 
     If Label6.Text = 60 Then 
      Label6.Text = 0 
      Label5.Text += 1 
     ElseIf Label5.Text = 60 Then 
      Label5.Text = 0 
      Label4.Text += 1 
     End If 

    End Sub 
    Private Sub Timer3_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer3.Tick 
     Label12.Text = Label12.Text + 1 
     If Label12.Text = 60 Then 
      Label12.Text = 0 
      Label11.Text += 1 
     ElseIf Label11.Text = 60 Then 
      Label11.Text = 0 
      Label10.Text += 1 
     End If 

    End Sub 

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 

    End Sub 
End Class

來源

2015-10-16 Dean

哎喲，看你的鍵盤隊友！關閉CAPS鎖只是輕輕一點。 – fujiFX

不看C＃給我。請說明C＃如何與您的問題相關。 –

在第三次點擊代碼時會再次觸發'Timer2.Enabled'行，因此您應該重新安排'IF'條件。 – fujiFX

你的第二個elseif的條件和第三elseif的第一部分是相同的，這意味着第三個永遠不會執行它裏面的代碼，因爲它總是落入第二個條件。

這將使你的代碼更容易保持一個變量來跟蹤你需要啓動哪個計時器。此外，如果您使用case語句，那麼addig更多定時器是一項簡單的任務。

事情是這樣的：

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click 
     'declare a static variable which keeps its value 
     Static whichTimer As Integer = 0 
     'every time the button is clicked increment the value 
     whichTimer += 1 

     'now start the appropriate timer 
     Select Case whichTimer 
      Case 1 
       Timer1.Start() 
      Case 2 
       Timer2.Start() 
      Case 3 
       Timer3.Start() 
      Case Else 
       'don't care 
     End Select 

End Sub

來源

2015-10-16 07:40:37

您需要了解

如果和ELSEIF

之間的區別：第一條件匹配時，就不會去下一個條件在這種情況下該代碼必須檢查等等被替換這樣

If Timer1.Enabled = False Then 
    Timer1.Start() 
End If 

If Timer1.Enabled = True Then 
    Timer2.Start() 
End If 

If Timer1.Enabled = True And Timer2.Enabled = true Then 
    Timer3.Start() 
End If

編輯

根據你的評論，你可以做這樣的事情

Public Class Form1 
    Dim ClickCount as Integer 
    ClickCount = 0 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click 
     ClickCount = ClickCount + 1 
     If Timer1.Enabled = False and ClickCount = 1 Then 
      Timer1.Start() 
     ElseIf Timer1.Enabled = True and ClickCount = 2 Then 
      Timer2.Start() 
     ElseIf Timer1.Enabled = True And Timer2.Enabled = true and ClickCount = 3 Then 
      Timer3.Start() 
      ClickCount = 0; 
     End If 
    End Sub

來源

2015-10-16 04:16:11

我剛纔嘗試過，當我點擊按鈕時，所有3個計時器將同時運行。 – Dean

好吧，你想當你點擊第一次運行第一次計時器，然後點擊它運行第二次，並在第三次運行第三次..是嗎？ –

在你的代碼的問題是對的範圍，在這裏，如果一個條件在裏面找到（IF，ELSE IF，ELSE IF，ELSE）語句，然後代碼將進入該範圍，並且不會檢查其他條件。例如，

IF (CONDITION) 
..some code 
ELSE IF(CONDITION) // if this condition is found true, then compiler will not check other condtion 
..some code // this code will be executed only 
ELSE IF(CONDITION) 
..some code 
ELSE 
..some code

首先確保所有被啓用true或false，如下修改代碼：

 If Timer1.Enabled = False And Timer2.Enabled = False And Timer3.Enabled=False Then 
      Timer1.Start() 
    End If 
    If Timer1.Enabled = True And Timer2.Enabled = False And Timer3.Enabled=False Then 
      Timer2.Start() 
    End If 
    If Timer1.Enabled = True And Timer2.Enabled=True And Timer3.Enabled=False Then 
      Timer3.Start() 
    End If

來源

2015-10-16 04:27:42

您的代碼不會繼續執行第二ElseIf。由於第三次點擊該按鈕，語句Timer1.Enabled = True仍然爲真，它將輸入該代碼段。這使該部分啓用第三個計時器不可訪問。

你真正尋找：

Public Class Form1 

    Private Sub Button1_Click(ByVal sender As System.Object, _ 
      ByVal e As System.EventArgs) Handles Button1.Click 

     If Timer1.Enabled = True And Timer2.Enabled = True Then 
      Timer3.Start() 
     ElseIf Timer1.Enabled = True Then 
      Timer2.Start() 
     Else 
      Timer1.Start() 
     End If 

    End Sub 

    Private Sub Timer1_Tick(ByVal sender As System.Object, _ 
      ByVal e As System.EventArgs) Handles Timer1.Tick 

     Label1.Text = Label1.Text + 1 
     If Label1.Text = 60 Then 
      Label1.Text = 0 
      Label2.Text += 1 
     ElseIf Label2.Text = 60 Then 
      Label2.Text = 0 
      Label3.Text += 1 
     End If 

    End Sub 

    Private Sub Timer2_Tick(ByVal sender As System.Object, _ 
      ByVal e As System.EventArgs) Handles Timer2.Tick 

     Label6.Text = Label6.Text + 1 
     If Label6.Text = 60 Then 
      Label6.Text = 0 
      Label5.Text += 1 
     ElseIf Label5.Text = 60 Then 
      Label5.Text = 0 
      Label4.Text += 1 
     End If 

    End Sub 
    Private Sub Timer3_Tick(ByVal sender As System.Object, _ 
      ByVal e As System.EventArgs) Handles Timer3.Tick 

     Label12.Text = Label12.Text + 1 
     If Label12.Text = 60 Then 
      Label12.Text = 0 
      Label11.Text += 1 
     ElseIf Label11.Text = 60 Then 
      Label11.Text = 0 
      Label10.Text += 1 
     End If 

    End Sub 

    Private Sub Form1_Load(ByVal sender As System.Object, _ 
      ByVal e As System.EventArgs) Handles MyBase.Load 

    End Sub 
End Class

來源

2015-10-16 04:28:34

VB.NET如果ElseIf發生在計時器

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