《在VB中创建独立控制界面的 ActiveX Dll 部件》2000/02/01 的老帖找到还真不容易!

 由 Microsoft 所提出的部件对象模型 (COM) ,包括 Automation 和 ActiveX 规范。通过 ActiveX
部件技术可以把已创建的基于对象的部件组合起来,这些部件可以通过许多不同的工具来创建。应用"部
件软件开发"方法有代码重用、模块功能分明等许多好处。下面以创建独立的界面控制 ActiveX Dll 部
件为题,做进一步分析:

    以下两个 ActiveX Dll 部件均实现了"在部件内部响应事件",即:在类模块内引用带事件的对象,以
及在程序运行阶段动态添加控件(实现的技术细节可参阅《MSDN》)。
例2:在 Delphi 提供了 Splitter 控件,轻而易举就实现了窗体界面的分割视图,而在 VB 中要实现这一
    功能则要编写大量代码。
    可参阅 VB 6 的"树状视图列表视图拆分条"控件集或"VB 应用程序向导 --> 资源管理器样式"代码,
    现将其加工移植为 ActiveX Dll 部件:
        创建ActiveX Dll(命名为:EasyViews)工程,并在类模块(命名为:SplitView)
        添加如下代码:

Option Explicit
Dim mbMoving As Boolean

Const iError = 120
Const iErrorXY = 150
Const SplitterHW = 80

Dim LeftCtl As Control
Dim RightCtl As Control
Dim TopCtl As Control
Dim BottomCtl As Control

Dim WithEvents ImgSplitterH As Image
Dim WithEvents ImgSplitterV As Image

Dim PictureH As PictureBox
Dim PictureV As PictureBox

Dim WithEvents FormX As Form

Dim iMinWidth As Integer
Dim iMinHeight As Integer
Dim iLeftMargin As Integer
Dim iRightMargin As Integer
Dim iTopMargin As Integer
Dim iBottomMargin As Integer

Public Property Get LeftMargin() As Integer
       LeftMargin = iLeftMargin
End Property

Public Property Let LeftMargin(ByVal vNewValue As Integer)
       iLeftMargin = vNewValue
End Property

Public Property Get RightMargin() As Integer
       RightMargin = iRightMargin
End Property

Public Property Let RightMargin(ByVal vNewValue As Integer)
       iRightMargin = vNewValue
End Property

Public Property Get TopMargin() As Integer
       TopMargin = iTopMargin
End Property

Public Property Let TopMargin(ByVal vNewValue As Integer)
       iTopMargin = vNewValue
End Property

Public Property Get BottomMargin() As Integer
       BottomMargin = iBottomMargin
End Property
Public Property Let BottomMargin(ByVal vNewValue As Integer)
       iBottomMargin = vNewValue
End Property

Public Property Get MinWidth() As Integer
MinWidth = iMinWidth
End Property

Public Property Let MinWidth(ByVal vNewValue As Integer)
iMinWidth = vNewValue
End Property

Public Property Get MinHeight() As Integer
MinHeight = iMinHeight
End Property

Public Property Let MinHeight(ByVal vNewValue As Integer)
iMinHeight = vNewValue
End Property

Private Sub FormX_Load()
Dim temp As String

temp = "DynamicImageH"
On Error GoTo ErrorHandler
FormX.Controls.Add "VB.Image", temp, FormX
On Error GoTo 0
With FormX.Controls.Item(temp)
     .Visible = True
End With
Set ImgSplitterH = FormX.Controls.Item(temp)
ImgSplitterH.MousePointer = 7 'ccsizeEW

temp = "DynamicImageV"
On Error GoTo ErrorHandler
FormX.Controls.Add "VB.Image", temp, FormX
On Error GoTo 0
With FormX.Controls.Item(temp)
     .Visible = True
End With
Set ImgSplitterV = FormX.Controls.Item(temp)
ImgSplitterV.MousePointer = 9 'cc2sizeNS

temp = "DynamicPictureH"
On Error GoTo ErrorHandler
FormX.Controls.Add "VB.PictureBox", temp, FormX
On Error GoTo 0
Set PictureH = FormX.Controls.Item(temp)
PictureH.BorderStyle = 0
PictureH.BackColor = vbBlack

temp = "DynamicPictureV"
On Error GoTo ErrorHandler
FormX.Controls.Add "VB.PictureBox", temp, FormX
On Error GoTo 0

Set PictureV = FormX.Controls.Item(temp)

PictureV.BorderStyle = 0
PictureV.BackColor = vbBlack
LeftCtl.Move LeftMargin, TopMargin
ImgSplitterV.Move LeftCtl.Left + LeftCtl.Width, LeftCtl.Top, SplitterHW, LeftCtl.Height
RightCtl.Move ImgSplitterV.Left + SplitterHW, LeftCtl.Top
RightCtl.Height = LeftCtl.Height
ImgSplitterH.Move LeftCtl.Left, LeftCtl.Top + LeftCtl.Height, FormX.Width - LeftMargin - RightMargin, SplitterHW
BottomCtl.Move LeftCtl.Left, LeftCtl.Top + LeftCtl.Height + SplitterHW  'LeftCtl.Height

Exit Sub
ErrorHandler:
temp = temp & "X"
Resume
End Sub

Public Sub Create(LeftCtlX As Object, RightCtlX As Object, BottomCtlX As Object)
Set LeftCtl = LeftCtlX
Set RightCtl = RightCtlX
'Set TopCtl = TopCtlX
Set BottomCtl = BottomCtlX
Set FormX = LeftCtlX.Container
FormX_Load
End Sub

Private Sub FormX_Resize()
If FormX.WindowState <> vbMinimized Then
   If FormX.Width < LeftMargin + RightMargin + SplitterHW + MinWidth + LeftCtl.Width + iErrorXY Then
      FormX.Width = LeftMargin + RightMargin + SplitterHW + MinWidth + LeftCtl.Width + iErrorXY
   End If
   If FormX.Height < TopMargin + BottomMargin + SplitterHW + MinHeight + LeftCtl.Height + iErrorXY + iErrorXY + iErrorXY + 6 Then
      FormX.Height = TopMargin + BottomMargin + SplitterHW + MinHeight + LeftCtl.Height + iErrorXY + iErrorXY + iErrorXY + 6
   End If
   RightCtl.Width = FormX.Width - LeftCtl.Width - SplitterHW - LeftMargin - RightMargin - iErrorXY
   ImgSplitterH.Width = FormX.Width - LeftMargin - RightMargin - iErrorXY
   BottomCtl.Width = ImgSplitterH.Width
   BottomCtl.Height = FormX.Height - ImgSplitterH.Top - BottomMargin - SplitterHW - 405
End If
End Sub

Private Sub ImgSplitterH_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
With ImgSplitterH
     PictureH.Move .Left - 10, .Top, .Width + 30, .Height / 2
End With
PictureH.Visible = True
mbMoving = True
End Sub

Private Sub ImgSplitterH_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
If Button = vbLeftButton Then
   If mbMoving Then
      If Y + ImgSplitterH.Top < LeftCtl.Top + MinHeight Then
         PictureH.Top = LeftCtl.Top + MinHeight
      ElseIf Y + ImgSplitterH.Top > FormX.Height - BottomMargin - SplitterHW - MinHeight - iErrorXY - iErrorXY - iErrorXY Then
         PictureH.Top = FormX.Height - BottomMargin - SplitterHW - MinHeight - iErrorXY - iErrorXY - iErrorXY
      Else
         PictureH.Top = Y + ImgSplitterH.Top
      End If
   End If
 End If
End Sub

Private Sub ImgSplitterH_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single)
    LeftCtl.Height = PictureH.Top - LeftCtl.Top
    ImgSplitterV.Height = LeftCtl.Height
    RightCtl.Height = LeftCtl.Height
    ImgSplitterH.Top = PictureH.Top
    BottomCtl.Height = FormX.Height - ImgSplitterH.Top - BottomMargin - SplitterHW - 400 - 5
    BottomCtl.Top = PictureH.Top + SplitterHW
    PictureH.Visible = False
    mbMoving = False
End Sub

Private Sub ImgSplitterV_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
PictureV.Visible = True
With ImgSplitterV
     PictureV.Move .Left, .Top - 10, .Width / 2, .Height
End With
mbMoving = True
End Sub

Private Sub ImgSplitterV_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
If Button = vbLeftButton Then
   If mbMoving Then
      If X + ImgSplitterV.Left < LeftCtl.Left + MinWidth Then
         PictureV.Left = LeftCtl.Left + MinWidth
      ElseIf X + ImgSplitterV.Left > FormX.Width - SplitterHW - RightMargin - MinWidth - iErrorXY Then
         PictureV.Left = FormX.Width - SplitterHW - RightMargin - MinWidth - iErrorXY
      Else
         PictureV.Left = X + ImgSplitterV.Left
      End If
   End If
   PictureV.Height = LeftCtl.Height
End If
End Sub

Private Sub ImgSplitterV_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single)
ImgSplitterV.Left = PictureV.Left
LeftCtl.Width = PictureV.Left - LeftCtl.Left
RightCtl.Width = FormX.Width - LeftCtl.Width - SplitterHW - LeftMargin - RightMargin - iErrorXY '- iError - 200
RightCtl.Left = PictureV.Left + SplitterHW
PictureV.Visible = False
mbMoving = False
End Sub

至此该部件创建完成。
    接下来创建标准工程,并在窗体上绘制任意三个控件,如: TreeView、ListView、DataGrid,并编写
如下代码测试 EasyViews 部件的类 SplitView:

Option Explicit
Dim x As New EasyViews.SplitView
Private Sub Form_Load()
'...
x.TopMargin = 500 ' Toolbar1.Height + 100
x.LeftMargin = 1000
x.RightMargin = 1000
x.BottomMargin = 500 'StatusBar1.Height
x.MinHeight = 1000
x.MinWidth = 1200
x.Create TreeView1, ListView1, DataGrid1
'...
End Sub

例1:使用过 Delphi 和 PB 的人应该知道,她们的 Form 和 Window 不需编程,即可实现滚动窗口。而在
    VB 中要实现滚动窗口则需要编写一些代码了,可参阅 MSDN:
    《Scroll Bar 控件方案:创建可滚动的图形视口》,现将其加工移植为 ActiveX Dll
    部件:
        创建 ActiveX Dll(命名为: EasyViews )工程,并在类模块 (命名为:ScrollView) 中添加如下
        代码:

Option Explicit
Dim Picture1 As PictureBox
Dim Picture2 As PictureBox
Dim Picture3 As PictureBox

Dim WithEvents HScroll1 As HScrollBar
Dim WithEvents VScroll1 As VScrollBar
Dim WithEvents FormX As Form

Dim iWidth As Integer
Dim iHeight As Integer
Dim iLeft As Integer
Dim iTop As Integer

Dim iLeftMargin As Integer
Dim iRightMargin As Integer
Dim iTopMargin As Integer
Dim iBottomMargin As Integer

Dim bAlignForm As Boolean

Const iErrorXY = 135
Const dXY = 60

Public Sub Create(PictureBox As Object, Optional bAlignFormX As Boolean = True)
Set Picture2 = PictureBox
Set FormX = PictureBox.Container
bAlignForm = bAlignFormX
FormX_Load
End Sub

Private Sub FormX_Load()
Dim temp As String

temp = "DynamicPicture1"
On Error GoTo ErrorHandler
FormX.Controls.Add "VB.PictureBox", temp, FormX
On Error GoTo 0
With FormX.Controls.Item(temp)
     .Visible = True
End With
Set Picture1 = FormX.Controls.Item(temp)

temp = "DynamicPicture3"
On Error GoTo ErrorHandler
FormX.Controls.Add "VB.PictureBox", temp, FormX
On Error GoTo 0
With FormX.Controls.Item(temp)
     .Visible = True
End With
Set Picture3 = FormX.Controls.Item(temp)

temp = "DynamicHScroll1"
On Error GoTo ErrorHandler
FormX.Controls.Add "VB.HScrollBar", temp ', FormX
On Error GoTo 0
With FormX.Controls.Item(temp)
     .Visible = True
End With
Set HScroll1 = FormX.Controls.Item(temp)

temp = "DynamicHScroll1"
On Error GoTo ErrorHandler
FormX.Controls.Add "VB.VScrollBar", temp ', FormX
With FormX.Controls.Item(temp)
     .Visible = True
End With
Set VScroll1 = FormX.Controls.Item(temp)

HScroll1.TabStop = False
VScroll1.TabStop = False
Set Picture1.Container = Picture3
Set HScroll1.Container = Picture3
Set VScroll1.Container = Picture3
Set Picture2.Container = Picture1
'Picture3.BorderStyle = 0
Picture1.BorderStyle = 0
Picture2.BorderStyle = 0
If Not bAlignForm Then
   Picture3.Move Left, Top, Width, Height
   HScroll1.Move 0, Picture3.Height - HScroll1.Height - dXY, Picture3.Width - VScroll1.Width - dXY
   VScroll1.Move Picture3.Width - VScroll1.Width - dXY, 0, VScroll1.Width, Picture3.Height - HScroll1.Height - dXY
   Picture1.Move 0, 0, Picture3.Width - VScroll1.Width - dXY, Picture3.Height - HScroll1.Height - dXY
   Picture2.Move 0, 0
   HScroll1.LargeChange = HScroll1.Max / 5
   VScroll1.LargeChange = VScroll1.Max / 5
   If Picture1.Height >= Picture2.Height Then
      HScroll1.Width = Picture3.Width - dXY
      Picture1.Width = Picture3.Width - dXY
   End If
   If Picture1.Width >= Picture2.Width Then
      VScroll1.Height = Picture3.Height - dXY
      Picture1.Height = Picture3.Height - dXY
   End If
   HScroll1.Max = Picture2.Width - Picture1.Width '+ 10 '+ dXY
   VScroll1.Max = Picture2.Height - Picture1.Height ' + 10 '+ dXY
   HScroll1.SmallChange = 100
   VScroll1.SmallChange = 100
   HScroll1.Visible = (Picture1.Width < Picture2.Width)
   VScroll1.Visible = (Picture1.Height < Picture2.Height)
End If
Exit Sub
ErrorHandler:
temp = temp & "X"
Resume
End Sub

Private Sub FormX_Resize()
On Error Resume Next
If bAlignForm Then
   Picture3.Move LeftMargin, TopMargin, FormX.Width - LeftMargin - RightMargin - iErrorXY, FormX.Height - TopMargin - BottomMargin - iErrorXY - iErrorXY - iErrorXY
   HScroll1.Move 0, Picture3.Height - HScroll1.Height - dXY, Picture3.Width - VScroll1.Width - dXY
   VScroll1.Move Picture3.Width - VScroll1.Width - dXY, 0, VScroll1.Width, Picture3.Height - HScroll1.Height - dXY
   Picture1.Move 0, 0, Picture3.Width - VScroll1.Width - dXY, Picture3.Height - HScroll1.Height - dXY
   Picture2.Move 0, 0
   HScroll1.LargeChange = HScroll1.Max / 5
   VScroll1.LargeChange = VScroll1.Max / 5
   If Picture1.Height >= Picture2.Height Then
      HScroll1.Width = Picture3.Width - dXY
      Picture1.Width = Picture3.Width - dXY
   End If
   If Picture1.Width >= Picture2.Width Then
      VScroll1.Height = Picture3.Height - dXY
      Picture1.Height = Picture3.Height - dXY
   End If
   HScroll1.Max = Picture2.Width - Picture1.Width ' + dXY
   VScroll1.Max = Picture2.Height - Picture1.Height ' + dXY
   HScroll1.SmallChange = 100
   VScroll1.SmallChange = 100
   HScroll1.Visible = (Picture1.Width < Picture2.Width)
   VScroll1.Visible = (Picture1.Height < Picture2.Height)
End If
End Sub

Private Sub HScroll1_Change()
Picture2.Left = -HScroll1.Value
End Sub

Private Sub VScroll1_Change()
Picture2.Top = -VScroll1.Value
End Sub

Public Property Get Width() As Integer
       Width = iWidth
End Property

Public Property Let Width(ByVal vNewValue As Integer)
       iWidth = vNewValue
End Property

Public Property Get Height() As Integer
       Height = iHeight
End Property

Public Property Let Height(ByVal vNewValue As Integer)
       iHeight = vNewValue
End Property

Public Property Get Left() As Integer
       Left = iLeft
End Property

Public Property Let Left(ByVal vNewValue As Integer)
       iLeft = vNewValue
End Property

Public Property Get Top() As Integer
       Top = iTop
End Property

Public Property Let Top(ByVal vNewValue As Integer)
       iTop = vNewValue
End Property

Public Property Get LeftMargin() As Integer
       LeftMargin = iLeftMargin
End Property

Public Property Let LeftMargin(ByVal vNewValue As Integer)
       iLeftMargin = vNewValue
End Property

Public Property Get RightMargin() As Integer
       RightMargin = iRightMargin
End Property

Public Property Let RightMargin(ByVal vNewValue As Integer)
       iRightMargin = vNewValue
End Property

Public Property Get TopMargin() As Integer
       TopMargin = iTopMargin
End Property

Public Property Let TopMargin(ByVal vNewValue As Integer)
       iTopMargin = vNewValue
End Property

Public Property Get BottomMargin() As Integer
       BottomMargin = iBottomMargin
End Property

Public Property Let BottomMargin(ByVal vNewValue As Integer)
       iBottomMargin = vNewValue
End Property

至此该部件创建完成。
    接下来创建标准工程,并在窗体上绘制一 PictureBox(Picture1) 控件,再绘制一定数量的各种控件
在该 PictureBox 控件内,并编写如下代码测试 EasyViews 部件的类 ScrollView :

Option Explicit
Dim x As New EasyViews.ScrollView
Dim y As New EasyViews.ScrollView
Private Sub Form_Load()
'...
x.Left = 1000
x.Top = 200
x.Height = 3000
x.Width = 4000
x.TopMargin = 3000
x.LeftMargin = 500
x.RightMargin = 500
x.BottomMargin = 600
x.Create Picture2 ', False

y.Left = 2000
y.Top = 300
y.Height = 2500
y.Width = 4000
'y.TopMargin = 1000
y.LeftMargin = 1000
y.RightMargin = 1000
y.BottomMargin = 4000
y.Create Picture1, False

'...
End Sub

    该方案使调用部件的主程序代码简洁明了,使实现界面控制的"代码部件"与实现其它功能的代码分离,
界限分明、一目了然。