Visual Basic

<code>
' Handle the KeyDown event to determine the type of character entered into the control.
Private Sub textBox1_KeyDown(sender As Object, e As System.Windows.Forms.KeyEventArgs) _
         Handles textBox1.KeyDown
      
        ' Determine whether the keystroke is a number from the top of the keyboard.
        If e.KeyCode = 13 Then
           Call DoMyTask() ' That must be your procedure or function
        End If
    End Sub 

</code>

Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
    If Char.IsDigit(e.KeyChar) Then
        'Key was a digit
        Dim txtBox As TextBox = DirectCast(sender, TextBox)
        Dim value As Integer
        Dim newText As String = txtBox.Text.Remove(txtBox.SelectionStart, txtBox.SelectionLength)
        newText = newText.Insert(txtBox.SelectionStart, e.KeyChar.ToString)

        'If value of textbox will be greater then 45 ignore key
        If Integer.TryParse(newText, value) Then
            If value > 45 Then e.Handled = True
        End If
    ElseIf Not Char.IsControl(e.KeyChar) Then
        'Ignore key: It wasn't digit, backspace, enter, or delete
        e.Handled = True
    End If
End Sub

Private Sub Text1_Change(Index As Integer)
   If Val(Text1(Index).Text) > 45 Then Text1(Index).Text = 45: MsgBox "Please Enter A Number Between 0 to 45", vbCritical
End Sub
Private Sub Text1_KeyPrees(Index as integer,KeyAscii as integer)
     Same Last Code

End Sub