CODEWITHSUNDEEP
c#asp.net-mvc-4
codeseeker
codeseeker

Reputation: 196

why viewmodel can't get data from database?even though it return values

I have a view model class Paymentcart and inside that I have created object of another two classes payment and cart.

Class Paymentcart

namespace Temple.Models
{
    public class paymentcart
    {
        public cart cart { get; set; }
        public payment payment { get; set; }
    }
}

Class cart:

public class cart
{
         public long cid { get; set; }
         public long vid { get; set; }
         public long userid { get; set; }
         public long count { get; set; }
         public long tempid { get; set; }
         public string  name { get; set; }
         public string star { get; set; }
         public string dates { get; set; }
         public string vname { get; set; }
         public string vrate { get; set; }
         public string totalamount { get; set; }
         public int rows { get; set; }
}

Class payment:

public class payment
{
        public long cid { get; set; }
        public long vid { get; set; }
        public long userid { get; set; }

        public long tempid { get; set; }
        public string amt { get; set; }
        public string cname { get; set; }
        public long number { get; set; }
        public long securitycode { get; set; }
        public string expdate { get; set; }
        public string totalamount { get; set; }
}

But when I am putting value from the database, it shows "Null Exception" error (but the database does return values).

This is the controller code:

 List<paymentcart> qlist = new List<paymentcart>();
            using (SqlConnection con = new SqlConnection(connectionString))
            {
                using (SqlCommand cmd = new SqlCommand("getcart", con))
                {
                    cmd.CommandType = CommandType.StoredProcedure;
                      var q = new paymentcart();
                    q.cart = new cart();
                    cmd.Parameters.AddWithValue("@uid", uid);
                    con.Open();
                    SqlDataReader rd = cmd.ExecuteReader();
                    while (rd.Read())
                    {
                         q.cart.tempid = Convert.ToInt64(rd["TdId"]);
                          q.cart.userid  = Convert.ToInt32(rd["UserID"]);
                           q.cart.cid = Convert.ToInt32(rd["cid"]);
                           q.cart. vid = Convert.ToInt32(rd["v_id"]);
                            q.cart.name = Convert.ToString(rd["name"]);
                           q.cart. star = Convert.ToString(rd["star"]);
                           q.cart. dates = Convert.ToString(rd["dates"]);
                            q.cart.vname = Convert.ToString(rd["vname"]);
                           q.cart. vrate = Convert.ToString(rd["vrate"]);
                           qlist.Add(q);

                    }

                }

            }
            return qlist;

I have attached a screenshot here: Error Page

I don't know am using the correct method; please help me to solve this.

Upvotes: 1

Views: 111

Answers (2)

dev
dev

Reputation: 121

Please try below code:

public List<paymentcart> ViewCart(int uid)
        {
            List<paymentcart> qlist = new List<paymentcart>();
            using (SqlConnection con = new SqlConnection(connectionString))
            {

                using (SqlCommand cmd = new SqlCommand("getcart", con))
                {
                    cmd.CommandType = CommandType.StoredProcedure;

                    cmd.Parameters.AddWithValue("@uid", uid);
                    con.Open();
                    SqlDataReader rd = cmd.ExecuteReader();

                    while (rd.Read())
                    {
                        var q = new paymentcart();
                        q.cart = new cart();

                         q.cart.tempid = Convert.ToInt64(rd["TdId"]);
                          q.cart.userid  = Convert.ToInt32(rd["UserID"]);
                           q.cart.cid = Convert.ToInt32(rd["cid"]);
                           q.cart. vid = Convert.ToInt32(rd["v_id"]);
                            q.cart.name = Convert.ToString(rd["name"]);
                           q.cart. star = Convert.ToString(rd["star"]);
                           q.cart. dates = Convert.ToString(rd["dates"]);
                            q.cart.vname = Convert.ToString(rd["vname"]);
                           q.cart. vrate = Convert.ToString(rd["vrate"]);
                           qlist.Add(q);




                    }

                }

            }
            return qlist;
        }

Upvotes: 0

Prasad Telkikar
Prasad Telkikar

Reputation: 16049

You created instance of paymentcart, that is correct but you missed to create instance of cart class, while instantiating paymentcart class object, create object of cart class

something like

 var q = new paymentcart();
 q.cart = new Cart(); //This will resolve error related to object instantiation
 //^^^ This was missing, I used naming conventions to differentiate between class name and object name 
 //Your code goes here
 cmd.Parameters.AddWithValue("@uid", uid);
 con.Open();
 SqlDataReader rd = cmd.ExecuteReader();

Bonus : Always follow naming conventions to declare class name, property name and variable names

  • Your class name should start with Capital letter i.e. PascalCase
  • Your variable name should start with small letter i.e. camelCase

Upvotes: 2

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