VB 2010 Первый шанс исключение типа «System.InvalidCastException» произошло в Microsoft.VisualBasic.dll

Question

Я новичок в программировании в Visual Basic 2010. я получил эти ошибки:

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

Вот мой код.

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 

Answer 1

An InvalidCastException означает, что вы пытались обрабатывать объект как нечто иное, чем это не может быть. Например, вы не можете обрабатывать строку как целое число. Я бы сказал, что это связано с TabPage2. Я не вижу для этого никаких заявлений.