编程爱好者一定使用过金山词霸的即指即译功能，它实际上是首先从文本中分离出鼠标所在位置的单词，然后对照英汉信息数据库的相关信息进行翻译。下面的代码演示了如何从一个RECHTEXT文本框中分离出单词，并且将它显示在一个标签控件中。
启动vb6，建立一个标准exe工程，单击“工程”――“部件”，选中Microsoft rich text control6.0，单击“确定”按钮，然后在窗体中添加该控件，命名为rchMainText，在窗体底部添加一个标签控件命名为label1，双击窗体，写入以下代码：
Option Explicit
Private Const EM_CHARFROMPOS& = &HD7‘返回鼠标所在位置的字符指针
Private Type POINTAPI
X As Long
Y As Long
End Type‘鼠标位置坐标
Private 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 Function RichWordOver(rch As RichTextBox, X As Single, Y As Single) As String
’当鼠标移动到richtext控件时，分离出当前的单词
Dim pt As POINTAPI ‘鼠标指针坐标
Dim pos As Integer
Dim start_pos As Integer
Dim end_pos As Integer
Dim ch As String
Dim txt As String
Dim txtlen As Integer
pt.X = X \ Screen.TwipsPerPixelX
pt.Y = Y \ Screen.TwipsPerPixelY
‘获得鼠标所在位置
pos = SendMessage(rch.hWnd, EM_CHARFROMPOS, 0&, pt)
If pos <= 0 Then Exit Function
txt = rch.Text
For start_pos = pos To 1 Step -1
ch = Mid$(rch.Text, start_pos, 1)
’从当前字符开始查找0-9、a-z、A-Z和“-”以外的字符，因为它们不‘可能是单词的组成，据此可以判断出本单词第一个字母的位置
If Not ( _(ch >= "0" And ch <= "9") Or _(ch >= "a" And ch <= "z") Or _
(ch >= "A" And ch <= "Z") Or _ch = "_") Then Exit For
Next start_pos ‘找到后退出循环
start_pos = start_pos + 1‘纪录本单词开始位置
’从鼠标当前位置查找本单词的最后一个字母位置，判断原理同上
txtlen = Len(txt)
For end_pos = pos To txtlen
ch = Mid$(txt, end_pos, 1)
’ Allow digits, letters, and underscores.
If Not ( (ch >= "0" And ch <= "9") Or (ch >= "a" And ch <= "z") Or _
(ch >= "A" And ch <= "Z") Or _
ch = "_" _
) Then Exit For ‘找到后退出循环
Next end_pos
end_pos = end_pos - 1‘纪录最后一个单词位置
If start_pos <= end_pos Then
RichWordOver = Mid$(txt, start_pos, end_pos - start_pos + 1)
’利用MID函数取出该单词
End Function
Private Sub Form_Load() ‘程序运行时初始化RICHTEXT
On Error Resume Next
Me.Caption = App.Title ’添加应用程序标题
Me.Left = (Screen.Width - Me.Width) / 2
Me.Top = (Screen.Height - Me.Height) / 2 ’窗体具中
rchMainText.Text = "Button As Integer, Shift As Integer, X As Single, Y As Single"
End Sub
Private Sub rchMainText_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
’当鼠标移动到RICHTEXT时，开始激活单词分离过程
Dim txt As String‘分离出的单词
txt = RichWordOver(rchMainText, X, Y)‘单词判断
If label1.Caption <> txt Then
label1.Caption = txt
‘将返回的单词传递给LABEL1标签
End Sub
Private Sub Form_Unload(Cancel As Integer)
End
End Sub‘程序结束
