Find And Replace Method For RichTextBox
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An artcal about richtextbox control
Introduction
This article describes how to create a find and replace method for the RichTextBox control. It is easy to understand. If you develop a word processing application this method will be a grate gadget for you. You can create any method for any control like this.
How To Create It
1. First, create a new project and name it "FRRichTextBox"
2. Then we need to create a class RichTextBoxFR.vb. to create it, click on Add New Item button on the Standard Toolbar.
3. Select Class from the template and name it RichTextBoxFR.vb and Click on Add button.
4. We use inherits statement and derive our class from RichTextBox Class
Public Class RichTextBoxFR
Inherits RichTextBox
End Class
5. We create a FindAndReplace method with two arguments - FindText and ReplaceText.
Public Class RichTextBoxFR
Inherits RichTextBox
Public Sub FindAndReplace(ByVal FindText As String, ByVal ReplaceText As String)
Me.Find(FindText)
If Not Me.SelectionLength = 0 Then
Me.SelectedText = ReplaceText
Else
MsgBox("The following specified text was not found: " & FindText)
End If
End Sub
End Class
Me here is RichTextBox. We use Me.Find(FindText) to search the text of the RichTextBox control and select the text. If the search text is found, RichTextBox select it and SelectionLength of RichTextBox will be > 0. Then we use if else statement to replace that text as above.
6. Now we create another FindAndReplace method by overloading our previous FindAndReplace method. You can see that method has five arguments - FindText, ReplaceText, ReplaceAll, MatchCase and WholeWord
Public Class RichTextBoxFR
Inherits RichTextBox
Public Sub FindAndReplace(ByVal FindText As String, ByVal ReplaceText As String)
Me.Find(FindText)
If Not Me.SelectionLength = 0 Then
Me.SelectedText = ReplaceText
Else
MsgBox("The following specified text was not found: " & FindText)
End If
End Sub
Public Sub FindAndReplace(ByVal FindText As String, ByVal ReplaceText As String, ByVal ReplaceAll As Boolean, _
ByVal MatchCase As Boolean, ByVal WholeWord As Boolean)
Select Case ReplaceAll
Case False
If MatchCase = True Then
If WholeWord = True Then
Me.Find(FindText, RichTextBoxFinds.MatchCase Or RichTextBoxFinds.WholeWord)
Else
Me.Find(FindText, RichTextBoxFinds.MatchCase)
End If
Else
If WholeWord = True Then
Me.Find(FindText, RichTextBoxFinds.WholeWord)
Else
Me.Find(FindText)
End If
End If
If Not Me.SelectionLength = 0 Then
Me.SelectedText = ReplaceText
Else
MsgBox("The following specified text was not found: " & FindText)
End If
Case True
Dim i As Integer
For i = 0 To Me.TextLength 'We know that strings we have to replace < TextLength of RichTextBox
If MatchCase = True Then
If WholeWord = True Then
Me.Find(FindText, RichTextBoxFinds.MatchCase Or RichTextBoxFinds.WholeWord)
Else
Me.Find(FindText, RichTextBoxFinds.MatchCase)
End If
Else
If WholeWord = True Then
Me.Find(FindText, RichTextBoxFinds.WholeWord)
Else
Me.Find(FindText)
End If
End If
If Not Me.SelectionLength = 0 Then
Me.SelectedText = ReplaceText
Else
MsgBox(i & " occurrence(s) replaced")
Exit For
End If
Next i
End Select
End Sub
End Class
7. We can use RichTextBoxFinds enumerations (which enables us to specify how the search is performed when the Find method is called)such as MatchCase, WholeWord, for advance search by thinking logically.
8. When we use ReplaceAll = True, we do not know how many strings we have to replace, but we know that Strings we have to replace < textlength of the richtextbox. We use For Loop statement to implement it.
How To Use It
Now we have created our RichTextBoxFR control.
9. Select Build Menu --> Build Solution
10. Select RichTextBoxFR from the ToolBox and draw it on the form.
11. Create a new form as above and name it frmFind. This form has
i. Two TextBoxes :- FindTextBox and ReplaceTextBox
ii. Three Buttons :- btnReplaceAll, btnReplace and btnCancel
iii. Two CheckBoxes :- MatchCase, WholeWord
12. Here are the codes for the form
Public Class frmFind
Private Sub btnReplaceAll_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnReplaceAll.Click
If MatchCase.Checked Then
If WholeWord.Checked Then
frmMain.RichTextBoxFR1.FindAndReplace(FindTextBox.Text, ReplaceTextBox.Text, True, True, True)
Else
frmMain.RichTextBoxFR1.FindAndReplace(FindTextBox.Text, ReplaceTextBox.Text, True, True, False)
End If
Else ' If FindMe.MatchCase.Checked = False
If WholeWord.Checked Then
frmMain.RichTextBoxFR1.FindAndReplace(FindTextBox.Text, ReplaceTextBox.Text, True, False, True)
Else
frmMain.RichTextBoxFR1.FindAndReplace(FindTextBox.Text, ReplaceTextBox.Text, True, False, False)
End If
End If 'End FindMe.MatchCase.Checked
End Sub
Private Sub btnReplace_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnReplace.Click
If MatchCase.Checked Then
If WholeWord.Checked Then
frmMain.RichTextBoxFR1.FindAndReplace(FindTextBox.Text, ReplaceTextBox.Text, False, True, True)
Else
frmMain.RichTextBoxFR1.FindAndReplace(FindTextBox.Text, ReplaceTextBox.Text, False, True, False)
End If
Else 'If FindMe.MatchCase.Checked = False
If WholeWord.Checked Then
frmMain.RichTextBoxFR1.FindAndReplace(FindTextBox.Text, ReplaceTextBox.Text, False, False, True)
Else
frmMain.RichTextBoxFR1.FindAndReplace(FindTextBox.Text, ReplaceTextBox.Text, False, False, False)
End If
End If 'End FindMe.MatchCase.Checked
End Sub
End Class
History
created - 17 March 2006