how to update stock when we purchase items from dealer

Here i am going to show you that how to update stock when we purchase items from dealer in inventory management system, i show you here when you are purchase items from dealer then we will update our stock and moreover you can use this system in multiple environment like how to developed Stock management system in c#,how to developed Sales And Inventory System C#, C# tutorial for build inventory management system, how to developed supermarket management software, how to developed medical store management system