How to find?

How do i make so you only can type numbers in a DTextEntry?

[lua]    local AmountText = vgui.Create( "DTextEntry", AmountPanel )
AmountText:SetPos( 20,25 )
AmountText:SetTall( 20 )
AmountText:SetWide( 60 )
AmountText:SetEnterAllowed( true )
AmountText.OnEnter = function() end[/lua]

EDIT: Got it working now :rolleyes:

Allowed bytes: 48-57

DTextEntry:SetNumeric( bool )