create extended 'copy' of existing c# class

Question

There are many classes around like:

var db = new System.Data.SqlClient.SqlConnection();

you can use ist like:

db.Open();
db.Close();
//...

so what I'm searching for is a kind of perfect copy of the class:

public class SqlConnection{
    private System.Data.SqlClient.SqlConnection db;

    public SqlConnection() {
        //create SqlConnection
        db = new System.Data.SqlClient.SqlConnection();
    }
    public void Open() {
        db.Open();
    }
    //...
}

so that I can use it like a normal class, but with my own little customisations:

db.Open();
db.Close();
//...
db.MyOwnFunktion();

Is there a quick solution like a visual-studio-build-in function to do so?

Answer 1

One can do several things:

1. Inheritance - create your own class that will inherit from a different one and will add more functionality
2. Write extension methods - For your case of SqlConnection due to it being a sealed class that is what you should do (over option1)

---

Short example of extension method:

public static class Extensions
{
    public static void DoSomething(this SqlConnection connection, int input)
    {
        //Do something
    }
}

//And then when you want to use it:
SqlConnection connection = new SqlConnection();
connection.DoSomething(3);