How to overload static methods in C#

Let’s say I have an abstract generic class and a descendant:

public abstract class AuditObject<T&gt; : ActiveRecordBase<T&gt;;

(yes I’m using ActiveRecord) and

public class Employee : AuditObject<Employee&gt;

In both of them I define some static Methods, e.g.

public static DataTable GetLookupTable(String where, Int32 topRows)
{
  return doExtremelyCleverStuffToFetchData(where, topRows);
}

(in the Employee class you need public new static or else you get a compiler warning)

As the code is, when I call e.g.

DataTable myList = AuditObject<T&gt;.GetLookupTable("inactive = 0", 100);

…and T is Employee, the static method is not “overriden” i.e. the one that is executed is the method in AuditObject, not Employee .So in AuditObject I modified the static methods (in this example, GetLookupTable) like this :

public static DataTable GetLookupTable(String where, Int32 topRows)
{
  DataTable tbl = null;
  Boolean hasOverride = hasMethodOverride("GetLookupTable");
  if (hasOverride)
  {
    tbl = invokeStaticMethod<T&gt;("GetLookupTable", new Object[2] { where, topRows }) as DataTable;
  }
  else
  {
    tbl = doExtremelyCleverStuffToFetchData(where, topRows);
  }
  return tbl;
}

Here’s how I find out if the static method exists :

private static Boolean hasMethodOverride(String methodName)
{
  var methodQuery =
    from method in typeof(T).GetMethods(
    BindingFlags.Static | BindingFlags.Public | BindingFlags.InvokeMethod)
    where method.Name == methodName
    select method;
  return methodQuery.Count() > 0;
}

And here’s how the “override” method is called :

public static Object invokeStaticMethod<T&gt;(String MethodName, Object[] Args)
{
return typeof(T).InvokeMember(MethodName,
  BindingFlags.Public | BindingFlags.Static | BindingFlags.InvokeMethod,
  null, null, Args);
}

Voila ! When I call, say, DataTable myList = AuditObject<T>.GetLookupTable(“inactive = 0”, 100); and T is Employee, I get results from the static method defined in the Employee class.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s