在VB中用PictureBox控件实现特殊符号工具栏

　　在几年前的一个试题库项目里，有一个这样的需求，需要输入特殊符号。因为各种不同的试题中，需要使用的特殊符号特别多，并且，不同类型的客户，需要输入的题目多种多样，能够用到的特殊符号也是五花八门。因此系统内置的特殊符号很难满足所有用户的要求。

　　根据这种需求，需要在程序中实现特殊符号的输入，系统内部除了要内置比较丰富的特殊符号之外，还要允许用户根据自己的情况进行自定义。

　　笔者经过研究，虽然走了一些弯路，但是，最终还是使用PictureBox控件开发出了特殊符号工具栏。

　　先说一下研究的历程吧，说到工具栏，大家首先想到的是使用ToolBar工具栏控件，笔者开始也是使用的这个控件，但是遇到了一些问题。虽然ToolBar控件使用起来比较简单，但是在此需求下，有一些问题，如：

1、ToolBar的各个按钮需要使用图片，而系统中的特殊符号需要自定义，如果让用户自己做图片恐怕不太可行；

2、用程序实现在运行时动态添加ToolBar中的按钮，也比较麻烦；

3、特殊符号按钮数量比较多，速度是一个问题（笔者研究时，只加了30个左右的按钮，运行之后的速度就不行了，加载慢，运行时闪烁）；

　　针对以上问题，使用ToolBar控件，不太可行，因此马上转变思路，经过思考，决定采用PictureBox控件进行自绘工具栏，每个特殊符号按钮的鼠标移动、移出、点击、抬起效果与ToolBar工具栏按钮完全一样。特殊符号保存在文本文件中，动态加载，另外还可以写一个维护程序，维护这个特殊符号文件中的内容。

源码下载地址：http://www.j2soft.cn/static_html/200511241415296539admin.html

系统演示界面如下：

使用界面：

设置界面：

源码下载地址：http://www.j2soft.cn/static_html/200511241415296539admin.html

实现程序如下：
1、添加一个模块文件，内容如下：

Option Explicit

Public Type RECT
Left As Long
Top As Long
Right As Long
Bottom As Long
End Type

Public Const DC_ACTIVE = &H1
Public Const DC_ICON = &H4
Public Const DC_TEXT = &H8
Public Const DC_GRADIENT = &H20
Public Const DFCS_PUSHED = &H200
Public Const DFCS_CAPTIONCLOSE = &H0

Public Declare Function ReleaseCapture Lib "user32" () As Long
Public Declare Function DrawCaption Lib "user32" (ByVal hwnd As Long,ByVal hDC As Long,pcRect As RECT,ByVal un As Long) As Long
Public Declare Function DrawFrameControl Lib "user32" (ByVal hDC As Long,lpRect As RECT,ByVal un1 As Long,ByVal un2 As Long) As Long
Public Declare Function SetRect Lib "user32" (lpRect As RECT,ByVal X1 As Long,ByVal Y1 As Long,ByVal X2 As Long,ByVal Y2 As Long) As Long
Public Declare Function SetWindowText Lib "user32" Alias "SetWindowTextA" (ByVal hwnd As Long,ByVal lpString As String) As Long
Public Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long,ByVal wMsg As Long,ByVal wParam As Long,lParam As Any) As Long

Public Sub ErrView(ErrS As String)
MsgBox "应用程序产生错误！" & vbCrLf & "错误描述为：" & ErrS & "！",vbExclamation,"试题库!"
End Sub

2、窗口内容如下：

Option Explicit

Dim Ctl As Control
Dim TbFlag As Boolean,StartFlag As Boolean
Dim StrSpecial() As String
Dim IntLen As Integer,TbXo As Integer,TbYo As Integer
Dim SpecialIndexFirst As Integer,SpecialIndexLast As Integer

Private Sub CmdExit_MouseDown(Button As Integer,Shift As Integer,X As Single,Y As Single)
Dim rt As RECT

If Button = 1 Then
SetRect rt,13,11
DrawFrameControl cmdExit.hDC,rt,1,DFCS_PUSHED
End If

ReleaseCapture
End Sub

Private Sub CmdExit_MouseMove(Button As Integer,Y As Single)
Dim rt As RECT

If Button = 1 Then
SetRect rt,DFCS_PUSHED
ElseIf Button = 0 Then
SetRect rt,DFCS_CAPTIONCLOSE
End If
End Sub

'特殊符号工具栏的关闭按钮
Private Sub cmdexit_MouseUp(Button As Integer,Y As Single)
On Error GoTo Errhandle
Dim rt As RECT

SetRect rt,DFCS_CAPTIONCLOSE

PicSpecial.Visible = False
PicSpecial.Height = 25

Erase StrSpecial '重置特殊符号数组，释放内存
Ctl.SetFocus

Exit Sub
Errhandle:
ErrView Err.Description
End Sub

Private Sub CmdExit_Paint()
Dim rt As RECT

SetRect rt,DFCS_CAPTIONCLOSE
End Sub

Private Sub Form_Activate()
Set Ctl = Me.ActiveControl
mnuSpecialChar_Click
End Sub

Private Sub Form_Load()
SetWindowText Pic_Btns.hwnd,"特殊符号"
End Sub

Private Sub mnuSpecialChar_Click()
Dim i As Integer
Dim s As String

If Right(App.Path,1) <> "/" Then
s = App.Path + "/" + "Char.Chr"
Else
s = App.Path + "Char.chr"
End If

'检测字符集文件是否存在
If Dir(s) = "" Then
MsgBox "特殊字符集文件丢失！特殊工具栏里的按钮将不可用！",vbCritical,"警告"

Exit Sub
End If

'打开字符集文件
Open s For Input As #1
Line Input #1,s
Close #1 '关闭字符集文件

IntLen = Len(s) + 2
ReDim StrSpecial(IntLen)

For i = 1 To IntLen - 2
StrSpecial(i) = Mid(s,i,1)
Next

StrSpecial(IntLen - 1) = "(" & vbTab & vbTab & ")"
StrSpecial(IntLen) = "________"

If IntLen Mod 24 = 0 Then
Pic_Btn.Height = IntLen + 25
Else
Pic_Btn.Height = Int(IntLen / 24) * 24 + 49
End If

If Pic_Btn.Height <= 169 Then
PicSpecial.Height = Pic_Btn.Height
PicSpecial.Width = 583
Pic_Btns.Width = 581
Pic_Btn.Top = 20
cmdExit.Left = 566
Else
PicSpecial.Height = 169
PicSpecial.Width = 598
Pic_Btns.Width = 600
cmdExit.Left = 581
VScroll.Height = 150

VScroll.Min = -20
VScroll.Max = Pic_Btn.Height - 189
End If

If VScroll.Min = -20 Then VScroll.Value = -20

PicSpecial.Top = (Me.ScaleHeight - PicSpecial.ScaleHeight) - 50
PicSpecial.Left = (Me.ScaleWidth - PicSpecial.ScaleWidth) / 2

PicSpecial.Visible = True
End Sub

Private Sub Pic_Btns_MouseDown(Button As Integer,Y As Single)
On Error GoTo Errhandle
If Button = 1 Then
ReleaseCapture
SendMessage PicSpecial.hwnd,&HA1,2,0
End If

Exit Sub
Errhandle:
ErrView Err.Description
End Sub

Private Sub Pic_Btns_MouseMove(Button As Integer,Y As Single)
PicBtnDraw
End Sub

Private Sub Pic_Btns_Paint()
Dim rt As RECT

rt.Left = 0
rt.Top = 0
rt.Right = PicSpecial.ScaleWidth
rt.Bottom = 16

DrawCaption Pic_Btns.hwnd,Pic_Btns.hDC,DC_ACTIVE Or DC_GRADIENT Or DC_TEXT Or DC_ICON
End Sub

Private Sub VScroll_Change()
On Error Resume Next
Dim TmpI As Integer

TmpI = VScroll.Value + 20

If TmpI Mod 24 = 0 Then
Pic_Btn.Top = -VScroll.Value
Else
Pic_Btn.Top = (TmpI Mod 24) - VScroll.Value
End If
End Sub

Private Sub VScroll_GotFocus()
On Error Resume Next
Ctl.SetFocus
PicBtnDraw
End Sub

Private Sub Pic_Btn_GotFocus()
On Error Resume Next
Ctl.SetFocus
End Sub

'特殊符号工具栏按钮
Private Sub Pic_Btn_MouseDown(Button As Integer,Y As Single)
On Error GoTo Errhandle
Dim Tmp_Index As Integer

'确定特殊符号索引
Tmp_Index = 1 + X / 24 + (Y / 24) * 24

'判断索引是否在当前显示的区域内
If X >= 576 Or Tmp_Index < SpecialIndexFirst Or Tmp_Index > SpecialIndexLast Then Exit Sub

If Button = 1 Then
Dim Xs As Integer,Ys As Integer

Xs = X / 24
Ys = Y / 24

Pic_Btn.ForeColor = &H8000000F
Pic_Btn.Line (TbXo * 24,TbYo * 24)-(TbXo * 24 + 24,TbYo * 24)
Pic_Btn.Line (TbXo * 24,TbYo * 24)-(TbXo * 24,TbYo * 24 + 24)
Pic_Btn.Line (TbXo * 24 + 24,TbYo * 24 + 1)-(TbXo * 24 + 24,TbYo * 24 + 25)
Pic_Btn.Line (TbXo * 24,TbYo * 24 + 24)-(TbXo * 24 + 24,TbYo * 24 + 24)

Pic_Btn.ForeColor = vbWhite
Pic_Btn.Line (Xs * 24 + 24,Ys * 24 + 1)-(Xs * 24 + 24,Ys * 24 + 25)
Pic_Btn.Line (Xs * 24,Ys * 24 + 24)-(Xs * 24 + 24,Ys * 24 + 24)
Pic_Btn.ForeColor = vbBlack
Pic_Btn.Line (Xs * 24,Ys * 24)-(Xs * 24 + 24,Ys * 24)
Pic_Btn.Line (Xs * 24,Ys * 24)-(Xs * 24,Ys * 24 + 25)

TbXo = Xs
TbYo = Ys
TbFlag = True
End If

Exit Sub
Errhandle:
ErrView Err.Description
End Sub

'绘制特殊符号工具栏
Private Sub Pic_Btn_MouseMove(Button As Integer,Y As Single)
On Error Resume Next
Dim Tmp_Index As Integer

'确定特殊符号索引
Tmp_Index = 1 + X / 24 + (Y / 24) * 24

'判断索引是否在当前显示区域内
If X >= 576 Or Tmp_Index < SpecialIndexFirst Or Tmp_Index > SpecialIndexLast Then
Pic_Btn.ForeColor = &H8000000F

Pic_Btn.Line (TbXo * 24,TbYo * 24 + 24)

Exit Sub
End If

If TbFlag Then Exit Sub

Dim Xs As Integer,TbYo * 24 + 24)

Pic_Btn.ForeColor = vbBlack
Pic_Btn.Line (Xs * 24 + 24,Ys * 24 + 24)
Pic_Btn.ForeColor = vbWhite
Pic_Btn.Line (Xs * 24,Ys * 24 + 25)

TbXo = Xs
TbYo = Ys
End Sub

Private Sub Pic_Btn_MouseUp(Button As Integer,Y As Single)
'On Error GoTo Errhandle
Dim Tmp_Index As Integer

If Button = 1 Then
TbFlag = False

'确定特殊符号索引
Tmp_Index = 1 + X / 24 + (Y / 24) * 24

'判断索引是否在当前显示区域内
If X >= 576 Or Tmp_Index < SpecialIndexFirst Or Tmp_Index > SpecialIndexLast Then Exit Sub

If TypeOf Ctl Is TextBox Or TypeOf Ctl Is TextBox Then
StartFlag = True

Ctl.SelText = StrSpecial(Tmp_Index)
Ctl.SetFocus
End If
End If

Exit Sub
Errhandle:
ErrView Err.Description
End Sub

'重绘特殊符号工具栏
Private Sub Pic_Btn_Paint()
On Error GoTo Errhandle
Dim i As Integer,X As Integer,Y As Integer

'此函数的功能是：只重画显示的部分，而不是重画所有的特殊符号
Pic_Btn.ForeColor = vbBlack

'根据容器的顶点计算重画的顶部索引,如果顶点是20,则从第
'一个开始,否则从下一行开始Pic_Btn.Top 的范围始终小于等
'于-20,并且是按24的倍数递减的,即:-20,-44,-68,-92……
SpecialIndexFirst = 21 - Pic_Btn.Top

X = 5: Y = 5 + SpecialIndexFirst

'根据顶点索引,计算最后一个索引,一页显示144个特殊符号(6行,24列)
SpecialIndexLast = SpecialIndexFirst + 143
'判断是否超过实际的特殊符号个数
SpecialIndexLast = IIf(SpecialIndexLast > IntLen,IntLen,SpecialIndexLast)

'循环重画特殊符号
For i = SpecialIndexFirst To SpecialIndexLast
Pic_Btn.CurrentX = X
Pic_Btn.CurrentY = Y

If i = IntLen - 1 Then
Pic_Btn.Print "()"
Else
If i = IntLen Then
Pic_Btn.Print "__"
Else
Pic_Btn.Print StrSpecial(i)
End If
End If

X = X + 24
'够一行则从下一行的开头重新开始
If i Mod 24 = 0 Then X = 5: Y = Y + 24
Next

Exit Sub
Errhandle:
ErrView Err.Description
End Sub

Private Sub PicBtnDraw()
On Error Resume Next
Pic_Btn.ForeColor = &H8000000F

Pic_Btn.Line (TbXo * 24,TbYo * 24 + 24)

Dim rt As RECT

SetRect rt,DFCS_CAPTIONCLOSE

TbFlag = False
End Sub

　　至此，特殊符号工具栏实现完成，大家也许会说，现在的汉字输入法都内置很多特殊符号，并且word中也有很多的特殊符号。但是毕竟都是别人提供的，内容不允许修改，并且在自己的系统内部，使用时还要调用别的程序，比较麻烦。

源码下载地址：http://www.j2soft.cn/static_html/200511241415296539admin.html

（编辑：李大同）

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