title: Extending properties of common library
body: <p>We are developing a product for different customers (ASP.NET solution), the solution consists of 3 VS projects, Business Entities, Business Services and Web.
  Each customer might need some customization, so we will need to make some changes on these 3 project.</p>
  
  <p>Business entities project contains classes with properties only, and Business Services contains classes with methods only and these methods use Business Entities classes.</p>
  
  <p>My problem is that i don't want to duplicate these 2 projects (Entities, Services) for each customer since they will have almost the same code.</p>
  
  <p>I thought about making Entities and Services as common library, and reference them in each new solution, and if customer needs some customization, i can extend these two library.</p>
  
  <p>Extension Methods helped me to extend 'Business Services' classes, but for 'Business Entities' classes i could not find a good solution to extend its properties, There is no Extension Properties in .NET.</p>
  
  <p>I thought about making partial classes, but i don't know if this is a good practice.</p>
  
  <p>Does anyone have a better solution?</p>