VB.net实例
1 生成txt文件。
创新互联建站服务紧随时代发展步伐，进行技术革新和技术进步，经过十年的发展和积累，已经汇集了一批资深网站策划师、设计师、专业的网站实施团队以及高素质售后服务人员，并且完全形成了一套成熟的业务流程，能够完全依照客户要求对网站进行网站设计制作、成都网站建设、建设、维护、更新和改版，实现客户网站对外宣传展示的首要目的，并为客户企业品牌互联网化提供全面的解决方案。
DimSaveFileDialog1AsNewSaveFileDialog() '创建一个保存对话框
SaveFileDialog1.Filter ="txt files (*.txt)|*.txt" '设置扩展名
IfSaveFileDialog1.ShowDialog() = System.Windows.Forms.DialogResult.OKThen '如果确定保存
My.Computer.FileSystem.WriteAllText(SaveFileDialog1.Filename, Textbox1.Text,False) '保存文本,False表示不追加文本，直接覆盖其内容
EndIf
原文链接：
求vb.net句柄实例，实现操作其他程序窗口。如我给的例子
Imports System.Text
Imports System.Runtime.InteropServices
Public Class Form1
' 相关API函数声明,注释掉的这里没用到，但是也比较常用吧，这些函数的功能都能搜到。
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As IntPtr
Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As IntPtr, ByVal hWnd2 As IntPtr, ByVal lpsz1 As String, ByVal lpsz2 As String) As IntPtr
Private Delegate Function EnumChildProc(ByVal hWnd As IntPtr, ByVal lParam As Integer) As Boolean
Private Declare Function EnumChildWindows Lib "user32.dll" (ByVal hWndParent As IntPtr, ByVal lpEnumFunc As EnumChildProc, ByVal lParam As Integer) As Boolean
Private Declare Auto Function SendMessage Lib "User32.dll" (ByVal hWnd As IntPtr, ByVal Msg As Integer, ByVal wParam As Integer, ByVal lParam As String) As Integer
'Private Declare Function CheckDlgButton Lib "user32" Alias "CheckDLGButtonA" (ByVal hDlg As IntPtr, ByVal nIDButton As IntPtr, ByVal wCheck As Integer) As Integer
Private Declare Function GetClassName Lib "user32" Alias "GetClassNameA" (ByVal hWnd As IntPtr, ByVal lpClassName As StringBuilder, ByVal nMaxCount As Integer) As Integer
'Private Declare Function GetWindowThreadProcessId Lib "user32" Alias "GetWindowThreadProcessId" (ByVal hwnd As IntPtr, ByVal lpdwProcessId As Long) As Integer
Private Declare Auto Function GetWindowTextLength Lib "user32" Alias "GetWindowTextLength" (ByVal hwnd As IntPtr) As Integer
Private Declare Function GetWindowText Lib "user32" Alias "GetWindowTextA" (ByVal hwnd As IntPtr, ByVal lpString As StringBuilder, ByVal cch As Integer) As Integer
' 相关消息定义，也有没用到的
Const WM_SETTEXT = HC
Const WM_GETTEXT = HD
'Const WM_SETFOCUS = H7
'Const WM_KILLFOCUS = H8
'Const WM_CLOSE = H10
'Const WM_SYSCOMMAND = H112
'Const SC_CLOSE = HF060
'Const SC_MINIMIZE = HF020
Const BM_GETCHECK = HF0
Const BM_SETCHECK = HF1
Const BM_GETSTATE = HF2
Const BM_SETSTATE = HF3
Const BM_SETSTYLE = HF4
Const BM_CLICK = HF5
'Const BM_GETIMAGE = HF6
'Const BM_SETIMAGE = HF7
Const BST_UNCHECKED = O0
Const BST_CHECKED = O1
Const BST_INDETERMINATE = O2
' 储存窗口句柄
Dim WindowHandle As IntPtr
' 储存两个（或者多个）编辑框句柄
Dim EditHandle As New List(Of IntPtr)
Dim EditWindowsText As List(Of String)
' 储存复选框句柄
Dim CheckHandle As IntPtr = 0
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Button1_Click(sender, e)
End Sub
' EnumChildWindows 回调函数，该函数名作为API函数EnumChildWindows 的一个参数
' 该函数实现了枚举各个子窗口，找出编辑框属性的功能
Public Function EnumChildProcC(ByVal hwnd As IntPtr, ByVal lParam As Integer) As Boolean
Dim dwWindowClass As StringBuilder = New StringBuilder(100)
' 获得某一个句柄的类名
GetClassName(hwnd, dwWindowClass, 100)
If dwWindowClass.ToString.Contains("EDIT") Or dwWindowClass.ToString.Contains("Edit") Then ' 类名包含EDIT的为编辑框
EditHandle.Add(hwnd) ' 存储该句柄
End If
' 返回 True 一直枚举完
Return True
End Function
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
WindowHandle = FindWindow(vbNullString, "登陆")
If WindowHandle.ToInt32 = 0 Then
MsgBox("未捕获到窗口" + "登陆")
Return
End If
' 枚举所有主窗口的子窗口（控件），枚举时自动调用回调函数，完成编辑框句柄的获取
EnumChildWindows(WindowHandle, AddressOf EnumChildProcC, 0)
' 寻找复选框
CheckHandle = FindWindowEx(WindowHandle, IntPtr.Zero, vbNullString, "记住密码")
Dim str As New StringBuilder
Dim j As Integer = 0
' 对编辑框文本赋值
For j = 0 To EditHandle.Count - 1
SendMessage(EditHandle(j), WM_SETTEXT, 0, "Text")
'GetWindowText(EditHandle(j), str, 20)
'EditWindowsText.Add(Str.ToString)
'Str.Clear()
Next
If EditHandle.Count = 0 Then
MsgBox("未找到输入框！")
End If
If CheckHandle.ToInt32 0 Then
'CheckDlgButton(WindowHandle, id, 1)
' 对复选框进行鼠标单击操作
SendMessage(CheckHandle, BM_CLICK, 0, 0)
'SendMessage(CheckHandle, BM_SETCHECK, True, 0)
End If
End Sub
End Class
VB.net中如何用timer控件编出一个简单的倒计时器？
用Timer控件吧，设置1秒执行1次。然后直接在Timer中写代码，将全全局的值来
减减1，如果值为0，则停止Timer
跳出提示框
以下示例：
int
Tatal
=
100;
Timer.Inveral
=
1000;
Timer_()
{
if
(
Tatal
==
0)
{
MessageBox.Show("完成！");
Timer.Stop();
}
else
{
Tatal
--;
}
}
用最简单的代码介绍一下指针在VB.net里面的用法？
例1：以下程序我们申请几个指向不同类型的指针：
’使用StructLayout(LayoutKind.Sequential)属性告诉net编译器:结构的元素在内存中按其出现的顺序排列
StructLayout(LayoutKind.Sequential) _
Public Structure DEFUDT_Test
Public bytb As Byte
Public i32a As Int32
End Structure
Public Function fnGetIntptr1() As IntPtr
’取得一个4字节数组指针
Dim tabytTest(3) As Byte
’以下语句告诉net垃圾回收进程不对tabytTest进行处理，也就是说tabytTest占用的内存区域固定不变。
Dim thObject As GCHandle = GCHandle.Alloc(tabytTest, GCHandleType.Pinned)
Dim tpObject As IntPtr = thObject.AddrOfPinnedObject() ’取得指向字节数组的指针
’取得一个指向32位内存数据的指针,
’由于使用gchandle取指针的方法只能对引用的对象有效，
’所以对如int32等值类型必须使用将其封装成为一个对象的方法以变为引用类型
Dim ti32Test As Object = Convert.ToInt32(0)
’以下语句告诉net垃圾回收进程不对ti32test进行处理，也就是说ti32Test的内存位置固定不变。
Dim thObject1 As GCHandle = GCHandle.Alloc(ti32Test, GCHandleType.Pinned)
Dim tpObject1 As IntPtr = thObject1.AddrOfPinnedObject() ’取得ti32Test的首地址
Dim tudtTest1 As DEFUDT_Test
’由于结构是一种值类型变量，为保证指针申请方便，我们申请
’取得一个和结构tudtTest1大小一致的字节数组指针,只要空间占用长度和结构一样就可以了
’由于net在结构封装中会插入额外的数据位，所以一定要用sizeof方法得到结构在非托管使用时的实际大小
Dim tudtTest(Marshal.SizeOf(tudtTest1)) As Byte
Dim thObject2 As GCHandle = GCHandle.Alloc(tudtTest, GCHandleType.Pinned)
Dim tpObject2 As IntPtr = thObject2.AddrOfPinnedObject() ’取得指向结构的指针
’在这儿你可以写对指针处理的任意代码(在例2中会给予补充)……
’在使用完毕后一定要释放指针指向的内存块，让垃圾回收器可对这个内存块回收处理
If thObject.IsAllocated Then
thObject.Free()
End If
If thObject1.IsAllocated Then
thObject1.Free()
End If
If thObject2.IsAllocated Then
thObject2.Free()
End If
End Function
上例中指针流程处理可以归纳为：
1、 定义一个具有合适内存长度的引用变量（关于引用变量和值变量的差异可以参观VB.NET的书籍）
2、使用GCHandle.Alloc方法将变量的内存区域固定下来。
3、使用GCHandle对象的AddrOfPinnedObject取得该内存区域的首地址并赋值给指针变量.
4、对指针进行操作
5、使用GCHandle对象的free方法释放指针指向的内存区域以便net垃圾回收器可以回收这个内存空间
2、指针所指向数据的存取
在.net中，对指针指向数据的存储函数都封装在marshal类中，主要的函数包括：Copy、PtrToStringUni 、PtrToStructure 、OffsetOf、WriteXXX,RreadXXX等，其中WriteXXX的表示向指针所表示的地址中写入XXX类型的数据，而ReadXXX中作用就是将指针所在地址的数据以XXX类型方式读出。看例程2，我们使用这些方法演示对例1那几个指向不同类型数据的指针作数据存/取操作。
例2：演示向例1申请得到的几个指针执行写入及读取数据的操作.
Marshal.WriteInt32(tpObject1, 0, Convert.ToInt32(77)) ’向ti32Test变量指向的地址写入32位整数77
MsgBox("现在ti32Test的值为:" ti32Test) ’因为变量存储地址的数据已改为77，所以显示为77
’以下这句之所以可行，因为ti32Test是32位整数，而tpObject指向的tabytTest数组刚好有4个元素
’而每一个byte元素都占用8位，合起来就是32位，和ti32Test占用的空间一样。这就印证了前面提’
’到的net中指针没有指向类型的说明。
Marshal.WriteInt32(tpObject, 0, ti32Test)
’以下代码再将tabytTest字节数组的内容理解为一个int32整数，
’并将值赋值给tudtTest结构中的int32元素
’我们使用Marshal.OffsetOf(GetType(DEFUDT_Test), "i32a").ToInt32以取得i32a元素在结构中的内存偏移位置
’所以New IntPtr(tpObject2.ToInt32 + Marshal.OffsetOf(GetType(DEFUDT_Test), "i32a").ToInt32)就临时产生了
’一个指针并指向i32a所在的内存地址(, 这个方法也说明了指针可以以字节为单位进行加减计算以指向合适的变量。
’Marshal.ReadInt32的作用是从指针中读取一个32整数。
Marshal.WriteInt32(New IntPtr(tpObject2.ToInt32 + Marshal.OffsetOf(GetType(DEFUDT_Test), "i32a").ToInt32), _
0, Marshal.ReadInt32(tpObject))
’这儿可以将字节数组的内容复制到真正的结构中
MsgBox(Marshal.OffsetOf(tudtTest1.GetType, "i32a").ToInt32)
tudtTest1 = CType(Marshal.PtrToStructure(tpObject2, GetType(DEFUDT_Test)), DEFUDT_Test)
MsgBox("结构tidtTest1中i32a元素的值为:" tudtTest1.i32a) ’此处将显示刚赋的值77
vb.net中如何用事件和委托，会C#中的事件和委托，但不知VB.net中的语法，望给个简单的例子熟悉语法。
一委托：此示例演示如何将方法与委托关联然后通过委托调用该方法。
创建委托和匹配过程
创建一个名为 MySubDelegate 的委托。
Delegate Sub MySubDelegate(ByVal x As Integer)
声明一个类，该类包含与该委托具有相同签名的方法。
Class class1
Sub Sub1(ByVal x As Integer)
MsgBox("The value of x is: " CStr(x))
End Sub
End Class
定义一个方法，该方法创建该委托的实例并通过调用内置的 Invoke 方法调用与该委托关联的方法。
Protected Sub DelegateTest()
Dim c1 As New class1
' Create an instance of the delegate.
Dim msd As MySubDelegate = AddressOf c1.Sub1
' Call the method.
msd.Invoke(10)
End Sub
二、事件
下面的示例程序阐释如何在一个类中引发一个事件，然后在另一个类中处理该事件。AlarmClock 类定义公共事件 Alarm，并提供引发该事件的方法。AlarmEventArgs 类派生自 EventArgs，并定义 Alarm 事件特定的数据。WakeMeUp 类定义处理 Alarm 事件的 AlarmRang 方法。AlarmDriver 类一起使用类，将使用 WakeMeUp 的 AlarmRang 方法设置为处理 AlarmClock 的 Alarm 事件。
该示例程序使用事件和委托和引发事件中详细说明的概念。
示例
' EventSample.vb.
'
Option Explicit
Option Strict
Imports System
Imports System.ComponentModel
Imports Microsoft.VisualBasic
Namespace EventSample
' Class that contains the data for
' the alarm event. Derives from System.EventArgs.
'
Public Class AlarmEventArgs
Inherits EventArgs
Private _snoozePressed As Boolean
Private nrings As Integer
'Constructor.
'
Public Sub New(snoozePressed As Boolean, nrings As Integer)
Me._snoozePressed = snoozePressed
Me.nrings = nrings
End Sub
' The NumRings property returns the number of rings
' that the alarm clock has sounded when the alarm event
' is generated.
'
Public ReadOnly Property NumRings() As Integer
Get
Return nrings
End Get
End Property
' The SnoozePressed property indicates whether the snooze
' button is pressed on the alarm when the alarm event is generated.
'
Public ReadOnly Property SnoozePressed() As Boolean
Get
Return _snoozePressed
End Get
End Property
' The AlarmText property that contains the wake-up message.
'
Public ReadOnly Property AlarmText() As String
Get
If _snoozePressed Then
Return "Wake Up!!! Snooze time is over."
Else
Return "Wake Up!"
End If
End Get
End Property
End Class
' Delegate declaration.
'
Public Delegate Sub AlarmEventHandler(sender As Object, _
e As AlarmEventArgs)
' The Alarm class that raises the alarm event.
'
Public Class AlarmClock
Private _snoozePressed As Boolean = False
Private nrings As Integer = 0
Private stopFlag As Boolean = False
' The Stop property indicates whether the
' alarm should be turned off.
'
Public Property [Stop]() As Boolean
Get
Return stopFlag
End Get
Set
stopFlag = value
End Set
End Property
' The SnoozePressed property indicates whether the snooze
' button is pressed on the alarm when the alarm event is generated.
'
Public Property SnoozePressed() As Boolean
Get
Return _snoozePressed
End Get
Set
_snoozePressed = value
End Set
End Property
' The event member that is of type AlarmEventHandler.
'
Public Event Alarm As AlarmEventHandler
' The protected OnAlarm method raises the event by invoking
' the delegates. The sender is always this, the current instance
' of the class.
'
Protected Overridable Sub OnAlarm(e As AlarmEventArgs)
RaiseEvent Alarm(Me, e)
End Sub
' This alarm clock does not have
' a user interface.
' To simulate the alarm mechanism it has a loop
' that raises the alarm event at every iteration
' with a time delay of 300 milliseconds,
' if snooze is not pressed. If snooze is pressed,
' the time delay is 1000 milliseconds.
'
Public Sub Start()
Do
nrings += 1
If stopFlag Then
Exit Do
Else
If _snoozePressed Then
System.Threading.Thread.Sleep(1000)
If (True) Then
Dim e As New AlarmEventArgs(_snoozePressed, nrings)
OnAlarm(e)
End If
Else
System.Threading.Thread.Sleep(300)
Dim e As New AlarmEventArgs(_snoozePressed, nrings)
OnAlarm(e)
End If
End If
Loop
End Sub
End Class
' The WakeMeUp class has a method AlarmRang that handles the
' alarm event.
'
Public Class WakeMeUp
Public Sub AlarmRang(sender As Object, e As AlarmEventArgs)
Console.WriteLine((e.AlarmText + ControlChars.Cr))
If Not e.SnoozePressed Then
If e.NumRings Mod 10 = 0 Then
Console.WriteLine(" Let alarm ring? Enter Y")
Console.WriteLine(" Press Snooze? Enter N")
Console.WriteLine(" Stop Alarm? Enter Q")
Dim input As String = Console.ReadLine()
If input.Equals("Y") Or input.Equals("y") Then
Return
Else
If input.Equals("N") Or input.Equals("n") Then
CType(sender, AlarmClock).SnoozePressed = True
Return
Else
CType(sender, AlarmClock).Stop = True
Return
End If
End If
End If
Else
Console.WriteLine(" Let alarm ring? Enter Y")
Console.WriteLine(" Stop Alarm? Enter Q")
Dim input As String = Console.ReadLine()
If input.Equals("Y") Or input.Equals("y") Then
Return
Else
CType(sender, AlarmClock).Stop = True
Return
End If
End If
End Sub
End Class
' The driver class that hooks up the event handling method of
' WakeMeUp to the alarm event of an Alarm object using a delegate.
' In a forms-based application, the driver class is the
' form.
'
Public Class AlarmDriver
Public Shared Sub Main()
' Instantiates the event receiver.
Dim w As New WakeMeUp()
' Instantiates the event source.
Dim clock As New AlarmClock()
' Wires the AlarmRang method to the Alarm event.
AddHandler clock.Alarm, AddressOf w.AlarmRang
clock.Start()
End Sub
End Class
End Namespace
vb.net 调用其他文件 如 dll
DLL（动态链接库）是一个很有用的东西，在开发大项目的时候显得非常重要，因为多人合作开发时，可以给每个人分配一个任务，用DLL完成，最后组合起来，就不会出现互相冲突的问题。这里给出最简单的DLL编写与调用的示例
首先，我们打开VB.NET，选择类库，名称改为test
然后输入以下代码
Public Class test
Public Function test(ByVal a As Long, ByVal b As Long) As Long
Return a + b
End Function
End Class
保存后，生成DLL文件。
这就是最简单的一个DLL，下面是调用该DLL的示例
新建一个工程，单击“项目” -- 添加引用
找到刚才生成的DLL，双击它
添加引用以后，似乎什么也没发生，这时我们输入以下代码：
Imports test.test
这样，就包含了该DLL的类。
然后我们定义一个类
Dim test As New test.test
这样，就可以使用里面的函数了，下面是程序示例
Imports test.test
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim test As New test.test
MsgBox(test.test(1, 2))
End Sub
End Class
运行该程序，可以看到，调用了DLL内的函数。
这就是最简单的DLL示例，可以将一些复杂的代码集成到DLL里，以后升级或重用都比较方便。
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