Oracle Stored Procedure List Parameters

I'm developing a .NET front end that interacts with an Oracle database. I have figured out how to get a list of stored procedures to execute, but I don't know how to get a list of parameters that belong to the stored procedure. I want to be able to show a list of all the parameters that are both input and output parameters for the stored procedure.

I have tried using the DBA_SOURCE, DBA_PROCEDURES, ALL_DEPENDENCIES, but I haven't seen anything that shows the parameters that belongs to the specified stored procedure.

Any ideas?

Solution

I believe that both responses I received are correct, but I ended up finding a different query which gives me exactly what I'm looking for:

    SELECT 
         ARGUMENT_NAME, 
         PLS_TYPE, 
         DEFAULT_VALUE
    FROM 
         USER_ARGUMENTS
    WHERE
         OBJECT_NAME = '<my_stored_proc>'

This has been working for me so far and pulls all the OracleParameter information that I want as well.