VB高级编程——VB的多线程

步骤一：建立一个Module添加如下代码：

 

Declare Function GetDC Lib "user32" () Declare Function GetDC Lib "user32" (ByVal hwnd As Long) As Long
Declare Function SetBkColor Lib "gdi32" () Declare Function SetBkColor Lib "gdi32" (ByVal hdc As Long, ByVal crColor As Long) As Long
Declare Function TextOut Lib "gdi32" Alias "TextOutA" () Declare Function TextOut Lib "gdi32" Alias "TextOutA" (ByVal hdc As Long, ByVal x As Long, ByVal y As Long, ByVal lpString As String, ByVal nCount As Long) As Long
Declare Function ReleaseDC Lib "user32" () Declare Function ReleaseDC Lib "user32" (ByVal hwnd As Long, ByVal hdc As Long) As Long

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

Declare Sub Sleep Lib "kernel32" () Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)

'全局的form的句柄！
Public formhandle As Long

OutText1() OutText1()    '过程一
        Dim i As Long
        Dim dc As Long
        Dim s As String
                dc = GetDC(formhandle) '获取窗体句柄的DC
                For i = 1 To 100000
                        s = CStr(i)
                        Call SetBkColor(dc, &HF0F0F0)    '设置绘制区域的背景色，也起清除作用
                        Call TextOut(dc, 10, 10, s, Len(s)) '输出文本！
                        Call Sleep(40) '等待
                Next
                Call ReleaseDC(formhandle, dc)    '释放资源！

End Sub

OutText2() OutText2()    '和过程一类似
        Dim i As Long
        Dim dc As Long
        Dim s As String
                dc = GetDC(formhandle)
                For i = 1 To 100000
                        s = CStr(i)
                        Call SetBkColor(dc, &HF0F0F0)
                        Call TextOut(dc, 10, 80, s, Len(s))    '文本位置改变了
                        Call Sleep(20) '延时改变了
                Next
                Call ReleaseDC(formhandle, dc)
End Sub

 

步骤二：建立一个窗体，添加如下组件，如图所示：

 

 

步骤三：在窗体中添加如下代码：

 

Sub Command1_Click() Sub Command1_Click()
        
        '声明了线程ID
        Dim threadid1 As Long
        Dim threadid2 As Long

        Call CreateThread(Null, ByVal O&, AddressOf Module1.OutText1, VarPtr(0), ByVal 0&, threadid1)
        Call CreateThread(Null, ByVal 0&, AddressOf Module1.OutText2, VarPtr(0), ByVal 0&, threadid2)
        
End Sub

Sub Form_Load() Sub Form_Load()
        '保存窗体句柄全局变量，用于在form 上绘图 
        formhandle = Form1.hwnd
End Sub

 

好，我们再来看运行效果，如图所示：

 

 

好了，本文实现了一个初步的多线程调用的例子！！