SQL Query says a parameter is not supplied, but is added to the SqlCommand object

Question

I have a stored procedure that has a parameter called UserName and in my code behind I have a SqlCommand object that I add the parameters to with the Add method. But for some reason when the command object tries to run the ExecuteReader method, it throws an exception. I am totally at a loss and have no idea why it's not recognizing the parameter. Before the ExecuteReader method is run I have a break point set so I can confirm the command object does contain the parameters being set, which is true. I know the stored procedure does return the correct data when the parameters are not added to the command object, but are hard coded in the actual stored procedure. Below is the exception message that is given in the catch block. I will also paste my code and first part of stored procedure. I would greatly appreciate any help in this issue, seeing that I have tried many different approaches to no avail. Thanks in advance.

Exception Message

Procedure or function 'someStoredProcedure' expects parameter '@UserName', which was not supplied.

Code Behind

private DataTable GetLossMitData(string code, DateTime? start, DateTime? end)  
{  
DataTable results = new DataTable();  
string connectionString = ConfigurationManager.ConnectionStrings["asdf"].ConnectionString;  
string userName = String.Empty;  

try  
{  
    using (SPSite site = new SPSite(ConfigurationManager.AppSettings["someName"]))  
    {  
        using (SPWeb web = site.OpenWeb())  
        {  
            userName = web.CurrentUser.Email.ToString();  
        }  
    }  

    using (SqlConnection connection1 = new SqlConnection(connectionString))  
    {  
         connection1.Open();  
         using (SqlCommand command1 = new SqlCommand("someStoredProcedure", connection1))  
         {  
             command1.Parameters.Add(new SqlParameter("@UserName", userName));  
             command1.Parameters.Add(new SqlParameter("@ProductCode", code));  

             SqlDataReader dr = command1.ExecuteReader(CommandBehavior.CloseConnection);  
             results.Load(dr);  
         }  
         connection1.Close();  
    }  
}  
catch (Exception ex)  
{  
}  
return results;  
}  

Stored Procedure

@UserName nvarchar(256),  
@ProductCode nvarchar(256),
@StartDate nvarchar(256) = '1/1/1900',
@EndDate nvarchar(256) = '12/30/2012'

AS
BEGIN
SET NOCOUNT ON;

Declare @UserID int

Select @UserID = Users.UserID
from Users
where Users.Email = @UserName

Answer 1

Try making sure that the command type is set to stored procedure.

mycommand.CommandType = System.Data.CommandType.StoredProcedure;