Question

Public Sub textcolorchanged()
    Dim searchword As String = RichTextBox2.Text.ToString.Trim

    Dim index1 As Integer = 0

    While index1 <> -1
      If (index1 < ORGFILETXT.Text.Length) Then
        index1 = ORGFILETXT.Find(searchword, index1, RichTextBoxFinds.None)
        'If (index1 <= ORGFILETXT.TextLength) Then
            If index1 <> -1 Then
                ORGFILETXT.SelectionStart = index1
                ORGFILETXT.SelectionLength = searchword.Length
                ORGFILETXT.SelectionColor = Color.Red
                index1 = index1 + searchword.Length
            End If
        'End If

      Else
          index1 = -1
      End if
    End While
End Sub

I searched word of datagridview1 rows and highlighted search word in rich text-box. text(it is having total text)
I called this method in datagridview1 mouse click and key-up and key down event

word is highlighted in rich text-box.text when I mouse click and key up and key down on datagridview1 rows of search word but some time getting full text is changed color how???
pls help me

Answer 1

Reading the documentation of RichTextBox.Find Method (String, Int32, RichTextBoxFinds) I have the suspect that, if the string is not found the return value is negative, but not -1.
If this is the case then it’s possible that your code fails in setting the selection color.

You could try to change this line

If index1 <> -1 Then 

with

If index1 >= 0 Then 

See also the their example in MSDN