add custom quantity in shopping cart in asp.net c#

using this tutorial you can understand that how yo can add custom quantity in shopping cart in asp.net c# and also on this time we will compare it in database also if that much quantity is not available in database then we are going to give error also and add custom quantity in shopping cart in asp.net c#,Adding Quantity Update Feature to Shopping Cart,c# - how to update shopping cart quantity,how to create shopping cart in asp net using c#,add to cart code in asp.net with cookies, shopping cart asp.net c#,asp.net shopping cart tutorial