Trying to insert a row using stored procedured with a parameter binded to an expression

Environment: asp.net 3.5 (C# and VB) , Ms-sql server 2005 express

Tables

Table:tableUser ID (primary key) username

Table:userSchedule ID (primary key) thecreator (foreign key = tableUser.ID) other fields

I have created a procedure that accepts a parameter username and gets the userid and inserts a row in Table:userSchedule

Problem: Using stored procedure with datalist control to only fetch data from the database by passing the current username using statement below works fine

protected void SqlDataSourceGetUserID_Selecting(object sender, SqlDataSourceSelectingEventArgs e)
    {
        e.Command.Parameters["@CurrentUserName"].Value = Context.User.Identity.Name; 
    }

But while inserting using DetailsView it shows error

Procedure or function OASNewSchedule has too many arguments specified. 

I did use

protected void SqlDataSourceCreateNewSchedule_Selecting(object sender, SqlDataSourceSelectingEventArgs e)
    {
        e.Command.Parameters["@CreatedBy"].Value = Context.User.Identity.Name;
    }

DetailsView properties: autogen fields: off, default mode: insert, it shows all the fields that may not be expected by the procedure like ID (primary key) not required in procedure and CreatedBy (user id ) field .

So I tried removing the 2 fields from detailsview and shows error

Cannot insert the value NULL into column 'CreatedBy', table 'D:\OAS\OAS\APP_DATA\ASPNETDB.MDF.dbo.OASTest'; column does not allow nulls. INSERT fails. The statement has been terminated.

For some reason parameters value is not being set.

Can anybody bother to understand this and help?

Ok my mistake, I didn't know how delegation works and what it was. Instead of SqlDataSourceCreateNewSchedule_Selecting(....) I should have used SqlDataSourceCreateNewSchedule_Inserting to modify the parameter after all the need was to set parameter while inserting not selecting.