Question about CRUD and viewing data and is there and easier way?

See more:

SQL

WPF

WinForms

ListView

DataGrid

, +

Hello I have a question about creating an insert query. Is there a way I can do Convert.DBNull with an int and a datetime? Also I would like to know the most efficient way I should be doing CRUD with C# WPF. I am currently using a listview to view my data from my DB I use a SqlCommand and a SqlDataReader to put my data into a list<myobject> and I use a foreach to add the list to the listview. I am wondering if I should be using a Datatable instead and possibly a DataGrid?

I am wondering if I could use a Create method like this?

public static void CreateProduct(Product product)
        {
            using (SqlConnection connection = ConnectionString.GetSqlConnection())
            {
                connection.Open();
                string sqlCreate = "INSERT INTO Products (ProductName, ProductPrice, ProductQuantity, " +
                    "ProductTax, ProductTotal, ProductListedDate, ProductPurchasedDate, UserID, ReceiptID " +
                    "VALUES(@pn, @pp, @pq, @pta, @pto, @pld, @ppd, @uid, @rid)";
                using (SqlCommand cmdCreate = new SqlCommand(sqlCreate, connection))
                {
                    cmdCreate.Parameters.AddWithValue("@pn", product.ProductName);
                    cmdCreate.Parameters.AddWithValue("@pp", product.ProductPrice);
                    cmdCreate.Parameters.AddWithValue("@pq", product.ProductQuantity);
                    cmdCreate.Parameters.AddWithValue("@pta", product.ProductTax);
                    cmdCreate.Parameters.AddWithValue("@pto", product.ProductTotal);
                    cmdCreate.Parameters.AddWithValue("@pld", product.ProductListedDate);
                    cmdCreate.Parameters.AddWithValue("@ppd", product.ProductPurchasedDate);
                    cmdCreate.Parameters.AddWithValue("@uid", product.UserID);       // ?? Convert.DBNull);
                    cmdCreate.Parameters.AddWithValue("@rid", product.ReceiptID);

                    cmdCreate.ExecuteNonQuery();
                }
            }
        }
//But this is the way I have my current create but I was wondering if I didn’t need @@IDENTITY
public static int CreateNewUser(User newUser)
        {
            string SQLinsertQuery = "INSERT INTO Users (Username, Password, IsAdmin, UserCreatedDate) " +
                                    "VALUES(@username, @password, @isadmin, @usercreateddate)";
            //SQL command
            SqlCommand cmdCreate = new SqlCommand(SQLinsertQuery, connection);
            cmdCreate.Parameters.AddWithValue("@username", newUser.Username);
            cmdCreate.Parameters.AddWithValue("@password", newUser.Password);
            cmdCreate.Parameters.AddWithValue("@isadmin", newUser.IsAdmin);
            cmdCreate.Parameters.AddWithValue("@usercreateddate", newUser.UserCreatedDate);
            try
            {
                connection.Open();
                cmdCreate.ExecuteNonQuery();
                string SQLselect = "SELECT @@IDENTITY FROM Users";
                SqlCommand cmdSelect = new SqlCommand(SQLselect, connection);
                int userId = Convert.ToInt32(cmdSelect.ExecuteScalar());
                return userId;
            }
            catch (SqlException sql)
            {
                sql.Message.ToString();
                throw sql;
            }
            catch (Exception ex)
            {
                ex.Message.ToString();
                return -1;
            }
            finally { connection.Close(); }
        }

What I have tried:

using listview and other create method