Auto-Refresh textbox in Realtime if Value Changes

AnusornKh 

Try this approach: 

You can add a timer to your userform and update the textbox value in the timer event. Here's an example code:

First, add a timer control to your userform from the toolbox (if it's not already there) and set its interval to the desired time (in milliseconds), for example, 1000 for 1 second.

Then, add the following code to your userform module:

Private Sub UserForm_Initialize()
    txtTotalPrice.Value = Sheets("Worksheet").Range("H17").Value
    Me.Timer1.Enabled = True ' start the timer
End Sub

Private Sub Timer1_Timer()
    txtTotalPrice.Value = Sheets("Worksheet").Range("H17").Value ' update the textbox value
End Sub

This will update the value in the textbox every time the timer interval elapses (in this case, every second). Note that you may need to adjust the interval based on your needs and the performance of your system.