Cannot derive classes from CommandEventArgs

[sumpun]

I have written something similar to this :

namespace mynamespace
{
public class MyOwnEventArgs : System.Web.UI.WebControls.CommandEventArgs=20
{
public int x ;
public MyOwnEventArgs()
{
x = 3;
}
}
}

However I keep on getting a compile error !!

Error CS1501: No overload for method 'CommandEventArgs' takes '0' arguments


Can someone help !!!???