another richtextbox question

I have been familiarising myself with the richtextbox so that I can use it in the future. What I've been trying to do is have to text of the box updated by code, but with different colours but I can't seem to get it right.

Whenever I add text to the box, it is like the formatting set for the previous text is lost (while stepping through the code, the previous formatting the lost when the new text is added). Here is the code I am using:

Option Explicit
Private Const msg = "123"

Private Sub Command1_Click()
    rtb.Text = rtb.Text & msg
    rtb.SelStart = Len(rtb.Text) - Len(msg)
    rtb.SelLength = Len(msg)
    rtb.SelBold = True
    rtb.SelLength = 0
End Sub

Private Sub Command2_Click()
    rtb.Text = rtb.Text & msg
    rtb.SelStart = Len(rtb.Text) - Len(msg)
    rtb.SelLength = Len(msg)
    rtb.SelBold = False
    rtb.SelLength = 0
End Sub

Thanks,
Sunny

[xmin]

Here is an analysis:

Option Explicit

Dim lngMsgLen As Long
Private Const msg = "123"

Private Sub Command1_Click()
    '
    'Your problem originates from the line "rtb.Text = rtb.Text & msg"
    'because every time you click on the command button the RichTextBox
    'is assigned a new value. When the new value is assigned, it
    'contains only the text itself but not the format. In order to obtain
    'your specific effect, you can use the following code. But if you
    'want to define formats at random, it seems that you have to use a
    'two dimention array to note down the positions and lengths.
    
    lngMsgLen = lngMsgLen + Len(msg)
    rtb.Text = rtb.Text & msg
    rtb.SelStart = Len(rtb.Text) - lngMsgLen
    rtb.SelLength = lngMsgLen
    rtb.SelBold = True
    rtb.SelLength = 0
    
End Sub

Thanks for the reply. I've also found another way, though shorter.

Option Explicit
Private Const Msg = "123"

Private Sub Command1_Click()
    rtb.SelBold = True
    rtb.SelColor = vbBlue
    rtb.SelText = Msg
End Sub

Sunny

[xmin]

Wow, that's much better, Sunnyl.