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用vb.net实现写字板程序报告（三）---by zigz(LuHai)luluhai@eastday.com
3） 关于查找替换功能这里我用了一个Panel面板控件来放查找，查找下一个，替换按钮和文本框。图4 查找替换我为什么不用一个窗体呢？因为我正好想练练拖动控件的代码，可以实现让这个面板在主窗体范围内拖动，由于看到了一个老外的教程，就顺便翻译了来练习练习。首先说说这个简单的查找替换功能，就是用户在第一个文本框中输入希望查找的字，然后点击查找按钮，程序就会在RichTextBox中查找相匹配的字，找到之后，将其高亮显示，点击下一个按钮，就会找到下一个匹配的字。。如此反复，直到结束，而替换就是把所有在RichTextBox中第一个文本框中的内容用第二个文本框的内容替换。是不是有些绕口令？还是亲自尝试一下就知道了。下面是查找替换相关代码（主要是创建一个FindText函数）：
'下面是关于实现查找功能
Dim MyPos As Integer '先声明一个全局变量
Private Sub FindText(ByVal start As Integer) '创建findtext函数
Dim pos As Integer
Dim target As String
'获取用户输入的要查找的字符串
target = txtbox.Text
pos = InStr(start, rtbox.Text, target)
If pos > 0 Then '找到了匹配字符串
MyPos = pos
rtbox.SelectionStart = MyPos - 1 '高亮显示
rtbox.SelectionLength = Len(txtbox.Text)
rtbox.Focus()
Else
MsgBox("没找到！")
End If
End Sub
给find按钮，findNext按钮
Private Sub find_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles find.Click
FindText(1)
End Sub
Private Sub findnext_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles findnext.Click
FindText(MyPos + 1)
End Sub
拖动控件的代码：
'下面这段程序，用作拖拽“查找面板”使用
Dim dragging As Boolean
Dim mousex As Integer
Dim mousey As Integer
Private Sub panel1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Panel1.MouseDown
If e.Button = MouseButtons.Left Then
dragging = True
mousex = -e.X
mousey = -e.Y
Dim clipleft As Integer = Me.PointToClient(MousePosition).X - Panel1.Location.X
Dim cliptop As Integer = Me.PointToClient(MousePosition).Y - Panel1.Location.Y
Dim clipwidth As Integer = Me.ClientSize.Width - (Panel1.Width - clipleft)
Dim clipheight As Integer = Me.ClientSize.Height - (Panel1.Height - cliptop)
Cursor.Clip = Me.RectangleToScreen(New Rectangle(clipleft, cliptop, clipwidth, clipheight))
Panel1.Invalidate()
End If
End Sub
Private Sub panel1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Panel1.MouseMove
If dragging Then
'移动控件到新的位置
Dim MPosition As New Point()
MPosition = Me.PointToClient(MousePosition)
MPosition.Offset(mousex, mousey)
'确实控件不能离开主窗口
Panel1.Location = MPosition
End If
End Sub
Private Sub panel1_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Panel1.MouseUp
If dragging Then
'结束拖拽
dragging = False
Cursor.Clip = Nothing
Panel1.Invalidate()
End If
End Sub
未完待续......
