DevOps, CI/CD and Automation

First of all, my goal is to return an array that I've defined back to C#.

Here is the type that I've defined:

create or replace type EMPARRAY is VARRAY(20) of VARCHAR2(30)

here is the function I'm trying to call

create or replace function getEmpArray 
Return EMPARRAY as  
  V_data EMPARRAY := EMPARRAY();
Cursor student_test is
  SELECT student_id 
  FROM students;
Begin
  For stu_rec In student_test
  Loop
    V_data.extend;
    V_data(V_data.count) := stu_rec.student_id;
  End loop;
  Return V_data;
END;

Now, I've installed the ODP.NET connector from oracle and am attempting to get that array returned but I'm having issues. Here is my c# code:

        public void test_Click(Object obj, EventArgs ea)
        {
            //create connection string
            String strConnection = "data source=foo;user id=foo;password=foo;";

            using (OracleConnection conn = new OracleConnection(strConnection))
            {
                OracleCommand objCmd = new OracleCommand();
                objCmd.Connection = conn;
                objCmd.CommandText = "getEmpArray";
                objCmd.CommandType = CommandType.StoredProcedure;
                OracleParameter returnValue = new OracleParameter("retVal", OracleCollectionType.PLSQLAssociativeArray);
                returnValue.Size = 100;
                returnValue.Direction = ParameterDirection.ReturnValue;
                objCmd.Parameters.Add(returnValue);

                try
                {
                    conn.Open();
                    Console.WriteLine("Connection Successful");
                }
                catch (OracleException e)
                {
                    MessageBox.Show(e.Message, "Oracle Exception");
                }
            }//end using
        }//end test Click

What I have compiles fine but when I fire the click event, it gives me an error saying that Object reference not set to an instance of an object. It points to this line:

OracleParameter returnValue = new OracleParameter("retVal", OracleCollectionType.PLSQLAssociativeArray);

So any suggestions on how I should go about doing this? I'm probably completely off base here so any help would be appreciated.