Help to convert to .net please!

[Edneeis]

Private Sub ChangeColor(ByVal word As String, ByVal clr As Color, ByVal rtb As RichTextBox, Optional ByVal start As Integer = 0)
        'find word
        Dim ret As Integer = rtb.Find(word, start, RichTextBoxFinds.WholeWord)
        If ret > -1 Then
            rtb.SelectionColor = clr
            If ret < rtb.Text.Length Then ChangeColor(word, clr, rtb, ret + 1)
        End If
    End Sub
 
'syntax
ChangeColor(txtWord.Text, Color.Blue, rtbText)

You could of course tie it to one RichTextBox or one color and cut out some of the parameters.