VB 2010「」類型的第一次機會異常出現在Microsoft.VisualBasic.dll中

-1

我在Visual是新的編程基礎2010年我有這些錯誤：VB 2010「」類型的第一次機會異常出現在Microsoft.VisualBasic.dll中

A first chance exception of type 'System.InvalidCastException' occurred in Microsoft.VisualBasic.dll

這裏的我的代碼。

Public Class Form1 

Private Sub CheckBox1_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckBox1.CheckedChanged 
    If TextBox2.ReadOnly = True Then 
     TextBox2.ReadOnly = False 
    End If 
End Sub 

Private Sub WebBrowser1_DocumentCompleted(ByVal sender As System.Object, ByVal e As System.Windows.Forms.WebBrowserDocumentCompletedEventArgs) 

End Sub 

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
    If TextBox3.ReadOnly = False Then 
     TextBox3.ReadOnly = True 
     TextBox3.Text = "|n/a|" 
    End If 
    If TextBox2.ReadOnly = False Then 
     TextBox2.ReadOnly = True 
    End If 
End Sub 

    Private Sub RadioButton1_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles RadioButton1.CheckedChanged 
    TextBox3.Text = "[1.5.2]" 
End Sub 

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click 
    If CheckBox1.Checked Then 
     Button1.Enabled = False 
     Threading.Thread.Sleep(500) 
     Button2.PerformClick() 
     Button3.PerformClick() 
     Button4.PerformClick() 
     Threading.Thread.Sleep(500) 
     If RichTextBox1.Text = Nothing Then 
      Threading.Thread.Sleep(5000) 
      Button3.PerformClick() 
      Button3.PerformClick() 
      Label4.Text = "Next try in 10 seconds" 
      Threading.Thread.Sleep(10000) 
      Label4.Text = "Trying...." 
      Button1.Enabled = True 
      Button1.PerformClick() 
     End If 
    End If 
End Sub 

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click 
    TabControl1.SelectedTab = TabPage2 
    Threading.Thread.Sleep(1000) 
    WebBrowser2.Navigate("https://login.minecraft.net?user=" + TextBox1.Text + "&password=" + TextBox2.Text + "&version=13") 

End Sub 

Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click 
    RichTextBox1.Text = WebBrowser2.DocumentText 
End Sub 

Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click 
    If WebBrowser2.DocumentText.Contains("Bad login") Then 
     MessageBox.Show("Bad login!") 
    End If 
    If WebBrowser2.DocumentText.Contains("User not premium") Then 
     MessageBox.Show("User not premium! Please buy Minecraft at the http://minecraft.net/ ") 
    End If 
    If RichTextBox1.Text.Contains("Bad login") Then 
     MessageBox.Show("Bad login!") 
    End If 
    If RichTextBox1.Text.Contains("User not premium") Then 
     MessageBox.Show("User not premium! Please buy Minecraft at the http://minecraft.net/ ") 
    End If 
End Sub 

End Class

來源

2013-10-27 user2925725

你在哪裏得到這個例外？我的意思是，任何線路號碼。或方法？ –

有兩件事Stackoverflow不是。代碼轉換器和代碼修復器。人們傾向於對「請將這些代碼轉換爲我」以及「我的代碼有什麼問題？」這樣的問題皺眉。話雖如此，我們通常會幫助人們提供他們最小的努力來研究他們的問題，然後再發布。在上面的例子中，對於錯誤肯定是＃行，並且根據這一點，您可能還想包含周圍變量的狀態。在失敗的行上放置一個斷點，在調試器中檢查這些斷點，並將這些信息包含在您的問題中。 – Neolisk

的InvalidCastException意味着你想處理一個對象以外的東西，它是不能夠被。例如，你不能像一個整數那樣處理一個字符串。我認爲這與TabPage2有關。我沒有看到任何聲明。

來源

2013-10-27 18:45:29 Matthias

VB 2010「」類型的第一次機會異常出現在Microsoft.VisualBasic.dll中

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