Properties should be very light weight that act and feel like fields. If you needs to access a database then you should use a method.
See MSDN here: http://msdn.microsoft.com/en-us/library/bzwdh01d(VS.71).aspx
Properties vs. Methods
Class library designers often must decide between implementing a class member as a property or a method. In general, methods represent actions and properties represent data. Use the following guidelines to help you choose between these options.
Use a property when
- The member is a logical data member. In the following member declarations, Name is a property because it is a logical member of the class.
Use a method when:
- The operation is a conversion, such as Object.ToString.
- The operation is expensive enough that you want to communicate to the user that they should consider caching the result.
- Obtaining a property value using the get accessor would have an observable side effect.
- Calling the member twice in succession produces different results.
- The order of execution is important. Note that a type's properties should be able to be set and retrieved in any order.
- The member is static but returns a value that can be changed.
- The member returns an array. Properties that return arrays can be very misleading. Usually it is necessary to return a copy of the internal array so that the user cannot change internal state. This, coupled with the fact that a user can easily assume it is an indexed property, leads to inefficient code. In the following code example, each call to the Methods property creates a copy of the array. As a result, 2n+1 copies of the array will be created in the following loop.