frmcommonexceptions.vb

Microsoft Mobile Development Handbook的代码,有C#,VB,C++的

Imports Microsoft.VisualBasic
Imports System
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Drawing
Imports System.Text
Imports System.Windows.Forms
Imports System.Net
Imports System.Diagnostics
Imports System.Net.Sockets

Namespace CodeForChapter4cs
  Public Partial Class frmCommonExceptions
	  Inherits Form
	Public Sub New()
	  InitializeComponent()
	End Sub

	Private Sub menuItem1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles menuItem1.Click
	  label1.Text = ".."
	  Try
		' Create a web request for a site.
		Dim wr As HttpWebRequest = CType(WebRequest.Create(textBox1.Text), HttpWebRequest)

		' Get the associated response for the above request.
		Dim rsp As HttpWebResponse = CType(wr.GetResponse(), HttpWebResponse)
		label1.Text = rsp.StatusCode.ToString()
		rsp.Close()
	  Catch ex As WebException
		Debug.WriteLine("This program is expected to throw WebException on successful run." & Constants.vbLf + Constants.vbLf & "Exception Message ")
		MessageBox.Show(ex.Message)

		If ex.Status = WebExceptionStatus.ProtocolError Then
		  If Not ex.Response Is Nothing Then
			'label1.Text = ((HttpWebResponse)ex.Response).StatusCode.ToString();
			Debug.WriteLine("Response is null")
			Return
		  End If
		  Debug.WriteLine("Status Code : " & (CType(ex.Response, HttpWebResponse)).StatusCode)
		  Debug.WriteLine("Status Description : " & (CType(ex.Response, HttpWebResponse)).StatusDescription)
		Else
		  Debug.WriteLine(ex.Status.ToString())
		End If

        If ex.InnerException IsNot Nothing Then
          Debug.WriteLine(ex.InnerException.ToString())
        Else
          Debug.WriteLine("was null")
        End If
      Catch ex2 As Exception
        Debug.WriteLine(ex2.Message)
	  End Try
	End Sub

Private Sub menuItem2_Click(ByVal sender As Object, ByVal e As EventArgs) Handles menuItem2.Click
  Try
	Dim ipAddress As IPAddress = Me.GetIpAddressSomehow()

	If ipAddress Is Nothing Then
	  MessageBox.Show("Sorry could not get ip address.")
	  Return
	End If

	Dim port As Integer
	Try
	  port = Convert.ToInt32(textBox1.Text)
	Catch e1 As FormatException
	  MessageBox.Show("Please provide a valid port number.")
	  Return
	End Try

	Dim ipe As IPEndPoint = New IPEndPoint(ipAddress, port)

	Try
	  Me.ConnectToThis(ipe)
	Catch ex As CantConnectException
	  LogException(ex)
	  MessageBox.Show("Sorry, could not connect")
	End Try
  Catch ex As Exception
	LogException(ex)
	MessageBox.Show("Sorry, an unexpected error has occured. Please shutdown this application.")
	ExitApplication()
  End Try
End Sub

	Private Sub ExitApplication()
	  Throw New Exception("The method or operation is not implemented.")
	End Sub

	Private Function GetIpAddressSomehow() As IPAddress
	  'throw new Exception("The method or operation is not implemented.");
	End Function

	Private Sub ConnectToThis(ByVal ep As IPEndPoint)

	End Sub


	Private Function ConnectToThis2(ByVal ep As IPEndPoint) As Boolean
	  Dim s As Socket = New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
	  Try
		s.Connect(ep)
		Return True
	  Catch e1 As SocketException
		' translate exception to return result
		Return False
	  Catch e2 As ArgumentNullException
		' IPEndPoint passed in is null. Pass it up, caller's fault.
		Throw
	  Catch ex As Exception
		LogException(ex) 'ouw own logging method
		Throw
	  End Try
	End Function

	Private Sub LogException(ByVal ex As Exception)
	  'throw new Exception("The method or operation is not implemented.");
	End Sub

	Public Event CantConnect As EventHandler

	Private Sub UpdateTimer(ByRef tmr As System.Threading.Timer)
	  Try
		tmr.Change(2000, 10000)
	  Catch e1 As ObjectDisposedException
		'tmr = new System.Threading.Timer(...);
		tmr.Change(2000, 10000)
	  End Try
	End Sub
  End Class
End Namespace