label_mess.Text = label_mess.Text & value should work.
How do you define btn.Tag ?
What variable type is value ?
You should post more code so we could find out what is wrong.
Best regards.
Here is a small part of my coding :
Sub Buttons_Click
Dim btn As Button
Dim Unit As String
Dim value As String
btn = Sender
Log("Button " & btn.Tag & " clicked") 'write the line to LogCat
If Current_Page=0 Then ' number's page
If btn.Tag="11" Then
value = "."
Else
value = btn.Tag
End If
Label_qty.Text = Label_qty.Text & value
Log("Label_qty=" & Label_qty.text)
For i = 0 To 1
Label_qty.Invalidate
DoEvents
Next
The logcat show correct result, but nothing on screen ????
Label_qty.text is set to "" in designer