This approach is great if you have a system that (for example) needs to allow technical users to add additional behaviours to the system by writing their own code, but if you as the developer are building/defining dynamic types, then the perfomance of this approach will be very very poor.

I want to create a class based on a base class (methods predefined) using data from a database.

In other words say I query tblTemplates for Templates and it returns 2 templates, and i query tblProperties for properties associated with these templates, I’d want to add to my base class

public class Template1
{
public string property1 { get; set; }
}
public class Template2
{
public string property1 { get; set; }
}