VB创建多线程应用程序(二)

2005-2-28　月光软件站

源代码如下：

窗体中的代码：

Option Explicit

'开始

Private Sub Command1_Click()

   On Error Resume Next

   With myThreadleft

        .Initialize AddressOf Fillleft            '传递过程地址给线程

        .ThreadEnabled = True

   End With

   With myThreadright

        .Initialize AddressOf Fillright

        .ThreadEnabled = True

   End With

   With myThreadbottom

        .Initialize AddressOf Fillbottom

        .ThreadEnabled = True

   End With

   MsgBox "多线程正在运行...，看看图片框控件的变色效果！", 64, "信息"

   '终止线程运行

   Set myThreadleft = Nothing

   Set myThreadright = Nothing

   Set myThreadbottom = Nothing

End Sub

'结束

Private Sub Command2_Click()

   Unload Me

End Sub

模块中的代码：

Option Explicit

'时间计数API

Private Declare Function GetTickCount Lib "kernel32" () As Long

'声明cls_thread类的对象变量

Public myThreadleft As New cls_thread, myThreadright As New cls_thread, myThreadbottom As New cls_thread

Sub Main()

   Load Form1

   Form1.Show

End Sub

Public Sub Fillleft()

       Static Bkgcolor As Long

       Dim LongTick As Long, Longcounter As Long

       On Error Resume Next

       For Longcounter = 0 To 3000

           DoEvents

           Bkgcolor = Longcounter Mod 256

           Form1.Picture1.BackColor = RGB(Bkgcolor, 0, 0)

           LongTick = GetTickCount

           While GetTickCount - LongTick < 10             '延时10毫秒,下同

           Wend

       Next

       Set myThreadleft = Nothing  '如果循环结束则终止当前线程运行，下同

End Sub

Public Sub Fillright()

       Static Bkgcolor As Long

       Dim LongTickValue As Long, Longcounter As Long

       On Error Resume Next

       For Longcounter = 0 To 3000

           DoEvents

           Bkgcolor = Longcounter Mod 256

           Form1.Picture2.BackColor = RGB(0, Bkgcolor, 0)

           LongTickValue = GetTickCount

           While GetTickCount - LongTickValue < 10

           Wend

       Next

Set myThreadright = Nothing

End Sub

Public Sub Fillbottom()

       Static Bkgcolor As Long

       Dim LongTick As Long, Longcounter As Long

       On Error Resume Next

       For Longcounter = 0 To 3000

           DoEvents

           Bkgcolor = Longcounter Mod 256

           Form1.Picture3.BackColor = RGB(0, 0, Bkgcolor)

           LongTick = GetTickCount

           While GetTickCount - LongTick < 10

           Wend

       Next

       Set myThreadright = Nothing

End Sub

类模块中的代码：

'功能：创建多线程类，用于初始化线程。   类名：cls_Thread 

'参数：LongPointFunction 用于接收主调过程传递过来的函数地址值

'调用方法：1.声明线程类对象变量 Dim mythread as cls_Thread

'          2.调用形式：With mythread

'                         .Initialize AddressOf 自定义过程或函数名 '(初始化线程) .

'                         .ThreadEnabled = True                  '(设置线程是否激活)

'                      End With                                       

'          3.终止调用： Set mythread = Nothing                                                                           

'   Crate By : 陈宇 On 2004.5.10     Copyright(C).Ldt By CY-soft 2001--2004                       

'   Email:4y4ycoco@163.com　 　　　　　　　　　                                                   

'   Test On： VB6.0+Win98  AND  VB6.0+WinXP     It's Pass ！                                   

Option Explicit

'创建线程API

'此API经过改造，lpThreadAttributes改为Any型，lpStartAddress改为传值引用：

'因为函数的入口地址由形参变量传递，如果用传址那将传递形参变量的地址而不是函数的入口地址

Private Declare Function CreateThread Lib "kernel32" (ByVal lpThreadAttributes As Any, ByVal dwStackSize As Long, ByVal lpStartAddress As Long, lpParameter As Any, ByVal dwCreationFlags As Long, LpthreadId As Long) As Long

'终止线程API

Private Declare Function TerminateThread Lib "kernel32" (ByVal hThread As Long, ByVal dwExitCode As Long) As Long

'激活线程API

Private Declare Function ResumeThread Lib "kernel32" (ByVal hThread As Long) As Long

'挂起线程API

Private Declare Function SuspendThread Lib "kernel32" (ByVal hThread As Long) As Long

Private Const CREATE_SUSPENDED = &H4    '线程挂起常量

'自定义线程结构类型

Private Type udtThread

        Handle As Long

        Enabled As Boolean

End Type

Private meTheard As udtThread

'初始化线程

Public Sub Initialize(ByVal LongPointFunction As Long)

       Dim LongStackSize As Long, LongCreationFlags As Long, LpthreadId As Long, LongNull As Long

       On Error Resume Next

       LongNull = 0

       LongStackSize = 0

       LongCreationFlags = CREATE_SUSPENDED         '创建线程后先挂起，由程序激活线程

       '创建线程并返线程句柄

       meTheard.Handle = CreateThread(LongNull, LongStackSize, ByVal LongPointFunction, LongNull, LongCreationFlags, LpthreadId)

       If meTheard.Handle = LongNull Then

          MsgBox "线程创建失败！", 48, "错误"

       End If

End Sub

'获取线程是否激活属性

Public Property Get ThreadEnabled() As Boolean

       On Error Resume Next

       Enabled = meTheard.Enabled

End Property

'设置线程是否激活属性

Public Property Let ThreadEnabled(ByVal Newvalue As Boolean)

       On Error Resume Next

       '若激活线程（Newvalue为真）设为TRUE且此线程原来没有激活时激活此线程

       If Newvalue And (Not meTheard.Enabled) Then

          ResumeThread meTheard.Handle

          meTheard.Enabled = True

       Else          '若激活线程（Newvalue为真）且此线程原来已激活则挂起此线程

          If meTheard.Enabled Then

             SuspendThread meTheard.Handle

             meTheard.Enabled = False

          End If

       End If

End Property

'终止线程事件

Private Sub Class_Terminate()

        On Error Resume Next

        Call TerminateThread(meTheard.Handle, 0)

End Sub

总结：

本程序的缺点是程序运行时CPU占用率高。

至此全部源代码结束，在实例的基础上可以根据个人需要做出不同的多线程应用程序，可以用此类模块创建ActiveX DLL，然后引用这个DLL来进行调用。希望对大家有用，若大家找到一种更好的实现方法且CPU占用率低的程序请通知我，程序中有什么Bug请Email，谢谢。