My suggestion. You can create a hashtable and populate it w/ your controls that should receive notification:
Private m_Controls As New Hashtable()
-In Form.Load, initialize your hash table; key is name of textbox.
m_Controls.Add(TextBox1.Name, TextBox1)
m_Controls.Add(TextBox2.Name, TextBox2)
-in event where you have to send message.
Dim strCtrlName, strMessage As String
-Extract control name and message; code left out...
CType(m_Controls(strCtrlName), TextBox).Text = strMessage