Sub keyboard_TextChanged (Old As String, New As String)
Dim ch As String
Dim allowedchar As String
allowedchar = "0123456789+*/-. ch"
ch = keyboard.Text
If allowedchar.Contains(ch) Then
If ch = 0 Then b0_Action
If ch = 1 OR ch = 2 OR ch = 3 OR ch = 4 OR ch = 5 OR ch = 6 OR ch = 7 OR ch = 8 OR ch = 9 Then
btn.Text = ch
keyboardinput = True
b_Action
End If
If ch = "+" Then bpl_Action
If ch = "/" Then bd_Action
If ch = "-" Then bmin_Action
If ch = "*" Then bmal_Action
If ch = "." Then bp_Action
If ch = "c" Then bc_Action
If ch = " " Then bg_Action
If ch = "h" Then his_Action
End If
keyboard.Text = ""
keyboard.RequestFocus
End Sub