Private Sub SearchTheText(ByVal sender As Object, ByVal e As SearchTextEventArgs)
MessageBox.Show(e.SearchText)
start = 0
indexOfSearchText = 0
Dim txtSearch As String = e.SearchText
Dim startindex As Integer = 0
If txtSearch.Length > 0 Then
startindex = FindMyText(txtSearch.Trim(), start, rtb.Text.Length)
End If
' If string was found in the RichTextBox, highlight it
If startindex >= 0 Then
' Set the highlight color as red
rtb.SelectionColor = Color.Red
' Find the end index. End Index = number of characters in textbox
Dim endindex As Integer = txtSearch.Length
' Highlight the search string
rtb.Select(startindex, endindex)
' mark the start position after the position of
' last search string
start = startindex + endindex
End If
End Sub
Public Function FindMyText(ByVal txtToSearch As String, ByVal searchStart As Integer, ByVal searchEnd As Integer) As Integer
' Unselect the previously searched string
If searchStart > 0 AndAlso searchEnd > 0 AndAlso indexOfSearchText >= 0 Then
rtb.Undo()
End If
' Set the return value to -1 by default.
Dim retVal As Integer = -1
' A valid starting index should be specified.
' if indexOfSearchText = -1, the end of search
If searchStart >= 0 AndAlso indexOfSearchText >= 0 Then
' A valid ending index
If searchEnd > searchStart OrElse searchEnd = -1 Then
' Find the position of search string in RichTextBox
indexOfSearchText = rtb.Find(txtToSearch, searchStart, searchEnd, RichTextBoxFinds.None)
' Determine whether the text was found in richTextBox1.
If indexOfSearchText <> -1 Then
' Return the index to the specified search text.
retVal = indexOfSearchText
End If
End If
End If
Return retVal
End Function