Replace button help

[ppstyle]

I have a replace button which has to replace a word that is searched inside the richtextbox(rtb).But the code is not working, help me identify my mistake. Thank you

 If HTMLopt.rtb.SelectedText.Length <> 0 Then
            HTMLopt.rtb.SelectedText = txtReplacementText.Text
        End If

        Dim StartPosition As Integer = HTMLopt.rtb.SelectionStart + 2
        Dim SearchType As CompareMethod

        If chkMatchCase.Checked = True Then
            SearchType = CompareMethod.Binary
        Else
            SearchType = CompareMethod.Text
        End If

        StartPosition = InStr(StartPosition, HTMLopt.rtb.Text, txtSearchTerm.Text, SearchType)

        If StartPosition = 0 Then
            MessageBox.Show("String: '" & txtSearchTerm.Text.ToString() & "' not found", "No Matches", MessageBoxButtons.OK, MessageBoxIcon.Asterisk)
            Exit Sub
        End If

        HTMLopt.rtb.Select(StartPosition - 1, txtSearchTerm.Text.Length)
        HTMLopt.rtb.ScrollToCaret()
        HTMLopt.rtb.Focus()

[tinstaafl]

What exactly is it doing/not doing?

[Begginnerdev]

Have you tried:

RichTextBox1.Text.Replace("ThisString","ThatString")

[ppstyle]

When I run this code on the click event of Replace button, the function says it cannot find the string

[tinstaafl]

It looks to me that you're replacing the selected text before you're searching the richtextbox, for an even different text. Is this what you intend?

[ppstyle]

I intend to search the given text and replace it by the text entered in replacementtext

[tinstaafl]

Try doing the replacement after the search is done, probably right after line 21.

[G_Waddell]

Hi,
As far as I can see there are two ways to do this, just use the replace function:

IF Instr(StartPosition,HTMLopt.rtb.text, txtSearchTerm.text,SearchType) = 0 then
    Messagebox.show("String :'" &txtSearchTerm.Text &"' not found", "No Matches", MessageboxButtons.OK, MessageboxIcon.Asterisk)
Else
    HTMLopt.rtb.Text.Replace(txtSearchTerm.Text,txtReplacement.Text)
End if

Or if you fancy scrolling through the textbox and replacing as you go something like this:

Clipboard.SetText(txtReplacementText.Text)
StartPosition = Instr(StartPosition,HTMLopt.rtb.text, txtSearchTerm.text,SearchType)
Do Until StartPosition = 0
    HTMlopt.rtb.Select(StartPosition-1, txtSearchterm.text.length)
    HTMLopt.rtb.ScrolltoCaret()
    application.DoEvents()
    HTMLopt.rtb.paste()
    Instr(StartPosition,HTMLopt.rtb.text, txtSearchTerm.text,SearchType)
Next