form1.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 CodeForChapter4vb_DLL.CodeForChapter4cs_DLL
Imports System.Diagnostics
Imports System.IO
Imports System.Collections
Imports System.Reflection

Namespace CodeForChapter4cs
  Public Partial Class Form1
	  Inherits Form
	Public Sub New()
	  InitializeComponent()
	End Sub

	Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
	 ' bool b;
	  Try

	  Catch e1 As Exception
		'ex.StackTrace
		Throw
	  End Try

	  Dim s As String = "start"
	  For i As Integer = 0 To 29
		s &= "let's kill our perf"
	  Next i

	  Me.ReturnSomething()
	End Sub

	Public Function ReturnSomething() As Integer
	  Return 5
	End Function

	Private Sub menuItem1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles menuItem1.Click
	  'this.SomeMethod();
	  Me.AnotherMethod(New SomeClass())
	End Sub

	Private Sub SomeMethod()
	  ' 1. let any exception bubble up
	  Me.MethodThatMayThrow()

	  ' 2. rethrow
	  Try
		Me.MethodThatMayThrow()
	  Catch e1 As Exception
		' do something with the exception object
		' or do something else as cleanup in this code block
		Throw 'rethrows
	  End Try

	  ' 3. Catch exception
	  Try
		Me.MethodThatMayThrow()
	  Catch e2 As Exception
		' FULLY deal with this exception
		'ex.st
	  End Try

	  ' 4. Swallow
	  Try
		Me.MethodThatMayThrow()
	  Catch e3 As Exception
		' swallow, just so it doesn't go up to other methods
		' DO NOT do this!
	  End Try
	End Sub


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

	Private Sub AnotherMethod(ByVal obj As SomeClass)
	  Try
		CType(obj, ISomeInterface).DoIt()
	  Catch ex As InvalidCastException
		' log the exception to file
		Debug.WriteLine("The stacktrace: " & Constants.vbCrLf & ex.StackTrace)
		' take some real recovery action!
	  End Try
	End Sub

	Private Sub menuItem2_Click(ByVal sender As Object, ByVal e As EventArgs) Handles menuItem2.Click
	  Dim obj As SomeType = Nothing
	  obj.SomeMethod() ' NullReferenceException
	End Sub

	Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles button1.Click
	  'this.DoSomethinginterestingWith(@"\testFile.txt");

	  Dim ar As ArrayList=Nothing
	  'ar.
	  ar.Capacity = 1
	  Me.WorkWithSomeList(ar)
	End Sub

	Private Sub DoSomethinginterestingWith(ByVal path As String)
	  Try
		Dim fs As FileStream = File.Open(path, FileMode.Open) 'FileNotFoundException
		' do something interesting with fs
	  Catch ex As FileNotFoundException
		' TODO deal with the invalid input
	  End Try
	End Sub


	'private void DoSomethinginterestingWith(string path)
	'{
	'  if (File.Exists(path))
	'  {
	'    FileStream fs = File.Open(path, FileMode.Open); //FileNotFoundException
	'    // do something interesting with fs
	'  }
	'  else
	'  {
	'    // TODO deal with the invalid input
	'  }
	'}

	'private void AnotherMethod(SomeClass obj)
	'{
	'  ISomeInterface i = obj as ISomeInterface;
	'  if (i != null)
	'  {
	'    ((ISomeInterface)obj).DoIt();
	'  }
	'  else
	'  {
	'    // Do something else!
	'  }
	'}

	Private Sub WorkWithSomeList(ByVal ar As ArrayList)
		ar.Add(New Object())
	  If Not(ar.IsFixedSize OrElse ar.IsReadOnly) Then
	  Else
		' do some sensible alternative
	  End If

	End Sub

	Private Sub button2_Click(ByVal sender As Object, ByVal e As EventArgs) Handles button2.Click
	  Dim t As Type = Me.GetType()
	  Dim m As MethodInfo = t.GetMethod("DoIt")
	  m.Invoke(Me, Nothing)
	End Sub

	Public Sub DoIt()
	  Throw New InvalidOperationException("my msg")
	End Sub
  End Class

  Public Class SomeType
	Public Sub SomeMethod()
	End Sub
  End Class
End Namespace