How do I get string value from stored procedure to C#?

ALTER PROCEDURE [dbo].[SP_InsTicketSale] 
(
@TktDate date, @TktId nvarchar(50),@Name nvarchar(50),  @Email nvarchar(50), @Mobile varchar(15),@TktStatus nvarchar(50)
,
@EmpId nvarchar(50),@TblLoc_ID varchar(3), @Promoid nvarchar(50), @TaxId nvarchar(50), @Grandtotal decimal(18,2),@subtotal decimal(18,2),

@Details ITEMDATA1   Readonly,

@id nvarchar(5) = NULL OUTPUT
)
AS
BEGIN


if not exists(select * from Tbl_TicketSale where TktId= @TktId)
	Begin
		declare @IdTmp	varchar(5)
    	set @IdTmp = 00000
  	    select @IdTmp = count(*) from Tbl_TicketSale
	   
	    set @IdTmp = @IdTmp + 1
	    set @TktId=   Right(('00000' + @IdTmp),5)

Begin Transaction


INSERT INTO Tbl_Client(TktDate, TktId, Name, Email, Mobile)
VALUES   (@TktDate, @TktId,@Name, @Email, @Mobile)


IF (@@ERROR <> 0) GOTO ERR_HANDLER	

INSERT INTO Tbl_TicketSale (TktId, EmpId, TktDate, TblLoc_ID,  TaxId, Grandtotal,subtotal,TktStatus)
VALUES  (@TktId , @EmpId, @TktDate, @TblLoc_ID, @TaxId , @Grandtotal ,@subtotal,'Delivered')


IF (@@ERROR <> 0) GOTO ERR_HANDLER	

--Temp Table
INSERT INTO Tbl_TicketSaleChild (TktId, ActivityId, Qty, PoxtypeAC, ActPrice, Amt, TktSale_childdate)
Select TktId=@TktId, tActivityId, tQty, tPoxtypeAC, tActPrice, tAmt, tTktSale_childdate from @Details ;

IF (@@ERROR <> 0) GOTO ERR_HANDLER	

End
Commit Transaction

 --RETURN 0
 Return @TktId 
 --select @TktId

ERR_HANDLER:
PRINT 'Unexpected error occurred!'
ROLLBACK Transaction
RETURN 1


END

//public int InsetTicketSale()
        public void InsetTicketSale()
        {
            int i = 0;
            try
            {

                SqlDBHelper SqlDb = new SqlDBHelper();
                SqlDb.CreateParameters("@TktDate", SqlDbType.Date, TktDate);
                SqlDb.CreateParameters("@TktId", SqlDbType.VarChar, TktId);
                SqlDb.CreateParameters("@Name", SqlDbType.VarChar, Name);
                SqlDb.CreateParameters("@Email", SqlDbType.VarChar, Email);
                SqlDb.CreateParameters("@Mobile", SqlDbType.VarChar, Mobile);
                SqlDb.CreateParameters("@EmpId", SqlDbType.VarChar, EmpId);
                SqlDb.CreateParameters("@TblLoc_ID", SqlDbType.VarChar, TblLoc_ID);
                SqlDb.CreateParameters("@Promoid", SqlDbType.VarChar, Promoid);
                SqlDb.CreateParameters("@TaxId", SqlDbType.VarChar, TaxId);
                SqlDb.CreateParameters("@Grandtotal", SqlDbType.Decimal, Grandtotal);
                SqlDb.CreateParameters("@subtotal", SqlDbType.Decimal, subtotal);
                SqlDb.CreateParameters("@Details", SqlDbType.Structured, Details);
                SqlDb.CreateParameters("@Servtax", SqlDbType.Decimal, Servtax);
                SqlDb.CreateParameters("@vat", SqlDbType.Decimal, vat);
                SqlDb.CreateParameters("@Tax3", SqlDbType.Decimal, Tax3);
                SqlDb.CreateParameters("@Servtaxp", SqlDbType.Decimal, Servtaxp);
                SqlDb.CreateParameters("@vatp", SqlDbType.Decimal, vatp);
                SqlDb.CreateParameters("@Tax3p", SqlDbType.Decimal, Tax3p);
                SqlDb.CreateParameters("@TktStatus", SqlDbType.VarChar, TktStatus);
                

                SqlDb.ProcedureName = "[SP_InsTicketSale]";

                i = Convert.ToInt32(SqlDb.ExecuteNonQueryReturn());
            }
            catch (Exception Excep)
            {
                throw new ApplicationException(Excep.Message);
            }
           // return i;
        }